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1. Two Sum 2. Add Two Numbers 3. Longest Substring Without Repeating Characters 4. Median of Two Sorted Arrays 5. Longest Palindromic Substring 6. Zigzag Conversion 7. Reverse Integer 8. String to Integer (atoi) 9. Palindrome Number 10. Regular Expression Matching 11. Container With Most Water 12. Integer to Roman 13. Roman to Integer 14. Longest Common Prefix 15. 3Sum 16. 3Sum Closest 17. Letter Combinations of a Phone Number 18. 4Sum 19. Remove Nth Node From End of List 20. Valid Parentheses 21. Merge Two Sorted Lists 22. Generate Parentheses 23. Merge k Sorted Lists 24. Swap Nodes in Pairs 25. Reverse Nodes in k-Group 26. Remove Duplicates from Sorted Array 27. Remove Element 28. Find the Index of the First Occurrence in a String 29. Divide Two Integers 30. Substring with Concatenation of All Words 31. Next Permutation 32. Longest Valid Parentheses 33. Search in Rotated Sorted Array 34. Find First and Last Position of Element in Sorted Array 35. Search Insert Position 36. Valid Sudoku 37. Sudoku Solver 38. Count and Say 39. Combination Sum 40. Combination Sum II 41. First Missing Positive 42. Trapping Rain Water 43. Multiply Strings 44. Wildcard Matching 45. Jump Game II 46. Permutations 47. Permutations II 48. Rotate Image 49. Group Anagrams 50. Pow(x, n) 51. N-Queens 52. N-Queens II 53. Maximum Subarray 54. Spiral Matrix 55. Jump Game 56. Merge Intervals 57. Insert Interval 58. Length of Last Word 59. Spiral Matrix II 60. Permutation Sequence 61. Rotate List 62. Unique Paths 63. Unique Paths II 64. Minimum Path Sum 65. Valid Number 66. Plus One 67. Add Binary 68. Text Justification 69. Sqrt(x) 70. Climbing Stairs 71. Simplify Path 72. Edit Distance 73. Set Matrix Zeroes 74. Search a 2D Matrix 75. Sort Colors 76. Minimum Window Substring 77. Combinations 78. Subsets 79. Word Search 80. Remove Duplicates from Sorted Array II 81. Search in Rotated Sorted Array II 82. Remove Duplicates from Sorted List II 83. Remove Duplicates from Sorted List 84. Largest Rectangle in Histogram 85. Maximal Rectangle 86. Partition List 87. Scramble String 88. Merge Sorted Array 89. Gray Code 90. Subsets II 91. Decode Ways 92. Reverse Linked List II 93. Restore IP Addresses 94. Binary Tree Inorder Traversal 95. Unique Binary Search Trees II 96. Unique Binary Search Trees 97. Interleaving String 98. Validate Binary Search Tree 99. Recover Binary Search Tree 100. Same Tree 101. Symmetric Tree 102. Binary Tree Level Order Traversal 103. Binary Tree Zigzag Level Order Traversal 104. Maximum Depth of Binary Tree 105. Construct Binary Tree from Preorder and Inorder Traversal 106. Construct Binary Tree from Inorder and Postorder Traversal 107. Binary Tree Level Order Traversal II 108. Convert Sorted Array to Binary Search Tree 109. Convert Sorted List to Binary Search Tree 110. Balanced Binary Tree 111. Minimum Depth of Binary Tree 112. Path Sum 113. Path Sum II 114. Flatten Binary Tree to Linked List 115. Distinct Subsequences 116. Populating Next Right Pointers in Each Node 117. Populating Next Right Pointers in Each Node II 118. Pascal's Triangle 119. Pascal's Triangle II 120. Triangle 121. Best Time to Buy and Sell Stock 122. Best Time to Buy and Sell Stock II 123. Best Time to Buy and Sell Stock III 124. Binary Tree Maximum Path Sum 125. Valid Palindrome 126. Word Ladder II 127. Word Ladder 128. Longest Consecutive Sequence 129. Sum Root to Leaf Numbers 130. Surrounded Regions 131. Palindrome Partitioning 132. Palindrome Partitioning II 133. Clone Graph 134. Gas Station 135. Candy 136. Single Number 137. Single Number II 138. Copy List with Random Pointer 139. Word Break 140. Word Break II 141. Linked List Cycle 142. Linked List Cycle II 143. Reorder List 144. Binary Tree Preorder Traversal 145. Binary Tree Postorder Traversal 146. LRU Cache 147. Insertion Sort List 148. Sort List 149. Max Points on a Line 150. Evaluate Reverse Polish Notation 151. Reverse Words in a String 152. Maximum Product Subarray 153. Find Minimum in Rotated Sorted Array 154. Find Minimum in Rotated Sorted Array II 155. Min Stack 156. Binary Tree Upside Down 157. Read N Characters Given Read4 158. Read N Characters Given read4 II - Call Multiple Times 159. Longest Substring with At Most Two Distinct Characters 160. Intersection of Two Linked Lists 161. One Edit Distance 162. Find Peak Element 163. Missing Ranges 164. Maximum Gap 165. Compare Version Numbers 166. Fraction to Recurring Decimal 167. Two Sum II - Input Array Is Sorted 168. Excel Sheet Column Title 169. Majority Element 170. Two Sum III - Data structure design 171. Excel Sheet Column Number 172. Factorial Trailing Zeroes 173. Binary Search Tree Iterator 174. Dungeon Game 175. Combine Two Tables 176. Second Highest Salary 177. Nth Highest Salary 178. Rank Scores 179. Largest Number 180. Consecutive Numbers 181. Employees Earning More Than Their Managers 182. Duplicate Emails 183. Customers Who Never Order 184. Department Highest Salary 185. Department Top Three Salaries 186. Reverse Words in a String II 187. Repeated DNA Sequences 188. Best Time to Buy and Sell Stock IV 189. Rotate Array 190. Reverse Bits 191. Number of 1 Bits 192. Word Frequency 193. Valid Phone Numbers 194. Transpose File 195. Tenth Line 196. Delete Duplicate Emails 197. Rising Temperature 198. House Robber 199. Binary Tree Right Side View 200. Number of Islands 201. Bitwise AND of Numbers Range 202. Happy Number 203. Remove Linked List Elements 204. Count Primes 205. Isomorphic Strings 206. Reverse Linked List 207. Course Schedule 208. Implement Trie (Prefix Tree) 209. Minimum Size Subarray Sum 210. Course Schedule II 211. Design Add and Search Words Data Structure 212. Word Search II 213. House Robber II 214. Shortest Palindrome 215. Kth Largest Element in an Array 216. Combination Sum III 217. Contains Duplicate 218. The Skyline Problem 219. Contains Duplicate II 220. Contains Duplicate III 221. Maximal Square 222. Count Complete Tree Nodes 223. Rectangle Area 224. Basic Calculator 225. Implement Stack using Queues 226. Invert Binary Tree 227. Basic Calculator II 228. Summary Ranges 229. Majority Element II 230. Kth Smallest Element in a BST 231. Power of Two 232. Implement Queue using Stacks 233. Number of Digit One 234. Palindrome Linked List 235. Lowest Common Ancestor of a Binary Search Tree 236. Lowest Common Ancestor of a Binary Tree 237. Delete Node in a Linked List 238. Product of Array Except Self 239. Sliding Window Maximum 240. Search a 2D Matrix II 241. Different Ways to Add Parentheses 242. Valid Anagram 243. Shortest Word Distance 244. Shortest Word Distance II 245. Shortest Word Distance III 246. Strobogrammatic Number 247. Strobogrammatic Number II 248. Strobogrammatic Number III 249. Group Shifted Strings 250. Count Univalue Subtrees 251. Flatten 2D Vector 252. Meeting Rooms 253. Meeting Rooms II 254. Factor Combinations 255. Verify Preorder Sequence in Binary Search Tree 256. Paint House 257. Binary Tree Paths 258. Add Digits 259. 3Sum Smaller 260. Single Number III 261. Graph Valid Tree 262. Trips and Users 263. Ugly Number 264. Ugly Number II 265. Paint House II 266. Palindrome Permutation 267. Palindrome Permutation II 268. Missing Number 269. Alien Dictionary 270. Closest Binary Search Tree Value 271. Encode and Decode Strings 272. Closest Binary Search Tree Value II 273. Integer to English Words 274. H-Index 275. H-Index II 276. Paint Fence 277. Find the Celebrity 278. First Bad Version 279. Perfect Squares 280. Wiggle Sort 281. Zigzag Iterator 282. Expression Add Operators 283. Move Zeroes 284. Peeking Iterator 285. Inorder Successor in BST 286. Walls and Gates 287. Find the Duplicate Number 288. Unique Word Abbreviation 289. Game of Life 290. Word Pattern 291. Word Pattern II 292. Nim Game 293. Flip Game 294. Flip Game II 295. Find Median from Data Stream 296. Best Meeting Point 297. Serialize and Deserialize Binary Tree 298. Binary Tree Longest Consecutive Sequence 299. Bulls and Cows 300. Longest Increasing Subsequence 301. Remove Invalid Parentheses 302. Smallest Rectangle Enclosing Black Pixels 303. Range Sum Query - Immutable 304. Range Sum Query 2D - Immutable 305. Number of Islands II 306. Additive Number 307. Range Sum Query - Mutable 308. Range Sum Query 2D - Mutable 309. Best Time to Buy and Sell Stock with Cooldown 310. Minimum Height Trees 311. Sparse Matrix Multiplication 312. Burst Balloons 313. Super Ugly Number 314. Binary Tree Vertical Order Traversal 315. Count of Smaller Numbers After Self 316. Remove Duplicate Letters 317. Shortest Distance from All Buildings 318. Maximum Product of Word Lengths 319. Bulb Switcher 320. Generalized Abbreviation 321. Create Maximum Number 322. Coin Change 323. Number of Connected Components in an Undirected Graph 324. Wiggle Sort II 325. Maximum Size Subarray Sum Equals k 326. Power of Three 327. Count of Range Sum 328. Odd Even Linked List 329. Longest Increasing Path in a Matrix 330. Patching Array 331. Verify Preorder Serialization of a Binary Tree 332. Reconstruct Itinerary 333. Largest BST Subtree 334. Increasing Triplet Subsequence 335. Self Crossing 336. Palindrome Pairs 337. House Robber III 338. Counting Bits 339. Nested List Weight Sum 340. Longest Substring with At Most K Distinct Characters 341. Flatten Nested List Iterator 342. Power of Four 343. Integer Break 344. Reverse String 345. Reverse Vowels of a String 346. Moving Average from Data Stream 347. Top K Frequent Elements 348. Design Tic-Tac-Toe 349. Intersection of Two Arrays 350. Intersection of Two Arrays II 351. Android Unlock Patterns 352. Data Stream as Disjoint Intervals 353. Design Snake Game 354. Russian Doll Envelopes 355. Design Twitter 356. Line Reflection 357. Count Numbers with Unique Digits 358. Rearrange String k Distance Apart 359. Logger Rate Limiter 360. Sort Transformed Array 361. Bomb Enemy 362. Design Hit Counter 363. Max Sum of Rectangle No Larger Than K 364. Nested List Weight Sum II 365. Water and Jug Problem 366. Find Leaves of Binary Tree 367. Valid Perfect Square 368. Largest Divisible Subset 369. Plus One Linked List 370. Range Addition 371. Sum of Two Integers 372. Super Pow 373. Find K Pairs with Smallest Sums 374. Guess Number Higher or Lower 375. Guess Number Higher or Lower II 376. Wiggle Subsequence 377. Combination Sum IV 378. Kth Smallest Element in a Sorted Matrix 379. Design Phone Directory 380. Insert Delete GetRandom O(1) 381. Insert Delete GetRandom O(1) - Duplicates allowed 382. Linked List Random Node 383. Ransom Note 384. Shuffle an Array 385. Mini Parser 386. Lexicographical Numbers 387. First Unique Character in a String 388. Longest Absolute File Path 389. Find the Difference 390. Elimination Game 391. Perfect Rectangle 392. Is Subsequence 393. UTF-8 Validation 394. Decode String 395. Longest Substring with At Least K Repeating Characters 396. Rotate Function 397. Integer Replacement 398. Random Pick Index 399. Evaluate Division 400. Nth Digit 401. Binary Watch 402. Remove K Digits 403. Frog Jump 404. Sum of Left Leaves 405. Convert a Number to Hexadecimal 406. Queue Reconstruction by Height 407. Trapping Rain Water II 408. Valid Word Abbreviation 409. Longest Palindrome 410. Split Array Largest Sum 411. Minimum Unique Word Abbreviation 412. Fizz Buzz 413. Arithmetic Slices 414. Third Maximum Number 415. Add Strings 416. Partition Equal Subset Sum 417. Pacific Atlantic Water Flow 418. Sentence Screen Fitting 419. Battleships in a Board 420. Strong Password Checker 421. Maximum XOR of Two Numbers in an Array 422. Valid Word Square 423. Reconstruct Original Digits from English 424. Longest Repeating Character Replacement 425. Word Squares 426. Convert Binary Search Tree to Sorted Doubly Linked List 427. Construct Quad Tree 428. Serialize and Deserialize N-ary Tree 429. N-ary Tree Level Order Traversal 430. Flatten a Multilevel Doubly Linked List 431. Encode N-ary Tree to Binary Tree 432. All O one Data Structure 433. Minimum Genetic Mutation 434. Number of Segments in a String 435. Non-overlapping Intervals 436. Find Right Interval 437. Path Sum III 438. Find All Anagrams in a String 439. Ternary Expression Parser 440. K-th Smallest in Lexicographical Order 441. Arranging Coins 442. Find All Duplicates in an Array 443. String Compression 444. Sequence Reconstruction 445. Add Two Numbers II 446. Arithmetic Slices II - Subsequence 447. Number of Boomerangs 448. Find All Numbers Disappeared in an Array 449. Serialize and Deserialize BST 450. Delete Node in a BST 451. Sort Characters By Frequency 452. Minimum Number of Arrows to Burst Balloons 453. Minimum Moves to Equal Array Elements 454. 4Sum II 455. Assign Cookies 456. 132 Pattern 457. Circular Array Loop 458. Poor Pigs 459. Repeated Substring Pattern 460. LFU Cache 461. Hamming Distance 462. Minimum Moves to Equal Array Elements II 463. Island Perimeter 464. Can I Win 465. Optimal Account Balancing 466. Count The Repetitions 467. Unique Substrings in Wraparound String 468. Validate IP Address 469. Convex Polygon 470. Implement Rand10() Using Rand7() 471. Encode String with Shortest Length 472. Concatenated Words 473. Matchsticks to Square 474. Ones and Zeroes 475. Heaters 476. Number Complement 477. Total Hamming Distance 478. Generate Random Point in a Circle 479. Largest Palindrome Product 480. Sliding Window Median 481. Magical String 482. License Key Formatting 483. Smallest Good Base 484. Find Permutation 485. Max Consecutive Ones 486. Predict the Winner 487. Max Consecutive Ones II 488. Zuma Game 489. Robot Room Cleaner 490. The Maze 491. Increasing Subsequences 492. Construct the Rectangle 493. Reverse Pairs 494. Target Sum 495. Teemo Attacking 496. Next Greater Element I 497. Random Point in Non-overlapping Rectangles 498. Diagonal Traverse 499. The Maze III 500. Keyboard Row 501. Find Mode in Binary Search Tree 502. IPO 503. Next Greater Element II 504. Base 7 505. The Maze II 506. Relative Ranks 507. Perfect Number 508. Most Frequent Subtree Sum 509. Fibonacci Number 510. Inorder Successor in BST II 511. Game Play Analysis I 512. Game Play Analysis II 513. Find Bottom Left Tree Value 514. Freedom Trail 515. Find Largest Value in Each Tree Row 516. Longest Palindromic Subsequence 517. Super Washing Machines 518. Coin Change II 519. Random Flip Matrix 520. Detect Capital 521. Longest Uncommon Subsequence I 522. Longest Uncommon Subsequence II 523. Continuous Subarray Sum 524. Longest Word in Dictionary through Deleting 525. Contiguous Array 526. Beautiful Arrangement 527. Word Abbreviation 528. Random Pick with Weight 529. Minesweeper 530. Minimum Absolute Difference in BST 531. Lonely Pixel I 532. K-diff Pairs in an Array 533. Lonely Pixel II 534. Game Play Analysis III 535. Encode and Decode TinyURL 536. Construct Binary Tree from String 537. Complex Number Multiplication 538. Convert BST to Greater Tree 539. Minimum Time Difference 540. Single Element in a Sorted Array 541. Reverse String II 542. 01 Matrix 543. Diameter of Binary Tree 544. Output Contest Matches 545. Boundary of Binary Tree 546. Remove Boxes 547. Number of Provinces 548. Split Array with Equal Sum 549. Binary Tree Longest Consecutive Sequence II 550. Game Play Analysis IV 551. Student Attendance Record I 552. Student Attendance Record II 553. Optimal Division 554. Brick Wall 555. Split Concatenated Strings 556. Next Greater Element III 557. Reverse Words in a String III 558. Logical OR of Two Binary Grids Represented as Quad-Trees 559. Maximum Depth of N-ary Tree 560. Subarray Sum Equals K 561. Array Partition 562. Longest Line of Consecutive One in Matrix 563. Binary Tree Tilt 564. Find the Closest Palindrome 565. Array Nesting 566. Reshape the Matrix 567. Permutation in String 568. Maximum Vacation Days 569. Median Employee Salary 570. Managers with at Least 5 Direct Reports 571. Find Median Given Frequency of Numbers 572. Subtree of Another Tree 573. Squirrel Simulation 574. Winning Candidate 575. Distribute Candies 576. Out of Boundary Paths 577. Employee Bonus 578. Get Highest Answer Rate Question 579. Find Cumulative Salary of an Employee 580. Count Student Number in Departments 581. Shortest Unsorted Continuous Subarray 582. Kill Process 583. Delete Operation for Two Strings 584. Find Customer Referee 585. Investments in 2016 586. Customer Placing the Largest Number of Orders 587. Erect the Fence 588. Design In-Memory File System 589. N-ary Tree Preorder Traversal 590. N-ary Tree Postorder Traversal 591. Tag Validator 592. Fraction Addition and Subtraction 593. Valid Square 594. Longest Harmonious Subsequence 595. Big Countries 596. Classes More Than 5 Students 597. Friend Requests I: Overall Acceptance Rate 598. Range Addition II 599. Minimum Index Sum of Two Lists 600. Non-negative Integers without Consecutive Ones 601. Human Traffic of Stadium 602. Friend Requests II: Who Has the Most Friends 603. Consecutive Available Seats 604. Design Compressed String Iterator 605. Can Place Flowers 606. Construct String from Binary Tree 607. Sales Person 608. Tree Node 609. Find Duplicate File in System 610. Triangle Judgement 611. Valid Triangle Number 612. Shortest Distance in a Plane 613. Shortest Distance in a Line 614. Second Degree Follower 615. Average Salary: Departments VS Company 616. Add Bold Tag in String 617. Merge Two Binary Trees 618. Students Report By Geography 619. Biggest Single Number 620. Not Boring Movies 621. Task Scheduler 622. Design Circular Queue 623. Add One Row to Tree 624. Maximum Distance in Arrays 625. Minimum Factorization 626. Exchange Seats 627. Swap Salary 628. Maximum Product of Three Numbers 629. K Inverse Pairs Array 630. Course Schedule III 631. Design Excel Sum Formula 632. Smallest Range Covering Elements from K Lists 633. Sum of Square Numbers 634. Find the Derangement of An Array 635. Design Log Storage System 636. Exclusive Time of Functions 637. Average of Levels in Binary Tree 638. Shopping Offers 639. Decode Ways II 640. Solve the Equation 641. Design Circular Deque 642. Design Search Autocomplete System 643. Maximum Average Subarray I 644. Maximum Average Subarray II 645. Set Mismatch 646. Maximum Length of Pair Chain 647. Palindromic Substrings 648. Replace Words 649. Dota2 Senate 650. 2 Keys Keyboard 651. 4 Keys Keyboard 652. Find Duplicate Subtrees 653. Two Sum IV - Input is a BST 654. Maximum Binary Tree 655. Print Binary Tree 656. Coin Path 657. Robot Return to Origin 658. Find K Closest Elements 659. Split Array into Consecutive Subsequences 660. Remove 9 661. Image Smoother 662. Maximum Width of Binary Tree 663. Equal Tree Partition 664. Strange Printer 665. Non-decreasing Array 666. Path Sum IV 667. Beautiful Arrangement II 668. Kth Smallest Number in Multiplication Table 669. Trim a Binary Search Tree 670. Maximum Swap 671. Second Minimum Node In a Binary Tree 672. Bulb Switcher II 673. Number of Longest Increasing Subsequence 674. Longest Continuous Increasing Subsequence 675. Cut Off Trees for Golf Event 676. Implement Magic Dictionary 677. Map Sum Pairs 678. Valid Parenthesis String 679. 24 Game 680. Valid Palindrome II 681. Next Closest Time 682. Baseball Game 683. K Empty Slots 684. Redundant Connection 685. Redundant Connection II 686. Repeated String Match 687. Longest Univalue Path 688. Knight Probability in Chessboard 689. Maximum Sum of 3 Non-Overlapping Subarrays 690. Employee Importance 691. Stickers to Spell Word 692. Top K Frequent Words 693. Binary Number with Alternating Bits 694. Number of Distinct Islands 695. Max Area of Island 696. Count Binary Substrings 697. Degree of an Array 698. Partition to K Equal Sum Subsets 699. Falling Squares 700. Search in a Binary Search Tree 701. Insert into a Binary Search Tree 702. Search in a Sorted Array of Unknown Size 703. Kth Largest Element in a Stream 704. Binary Search 705. Design HashSet 706. Design HashMap 707. Design Linked List 708. Insert into a Sorted Circular Linked List 709. To Lower Case 710. Random Pick with Blacklist 711. Number of Distinct Islands II 712. Minimum ASCII Delete Sum for Two Strings 713. Subarray Product Less Than K 714. Best Time to Buy and Sell Stock with Transaction Fee 715. Range Module 716. Max Stack 717. 1-bit and 2-bit Characters 718. Maximum Length of Repeated Subarray 719. Find K-th Smallest Pair Distance 720. Longest Word in Dictionary 721. Accounts Merge 722. Remove Comments 723. Candy Crush 724. Find Pivot Index 725. Split Linked List in Parts 726. Number of Atoms 727. Minimum Window Subsequence 728. Self Dividing Numbers 729. My Calendar I 730. Count Different Palindromic Subsequences 731. My Calendar II 732. My Calendar III 733. Flood Fill 734. Sentence Similarity 735. Asteroid Collision 736. Parse Lisp Expression 737. Sentence Similarity II 738. Monotone Increasing Digits 739. Daily Temperatures 740. Delete and Earn 741. Cherry Pickup 742. Closest Leaf in a Binary Tree 743. Network Delay Time 744. Find Smallest Letter Greater Than Target 745. Prefix and Suffix Search 746. Min Cost Climbing Stairs 747. Largest Number At Least Twice of Others 748. Shortest Completing Word 749. Contain Virus 750. Number Of Corner Rectangles 751. IP to CIDR 752. Open the Lock 753. Cracking the Safe 754. Reach a Number 755. Pour Water 756. Pyramid Transition Matrix 757. Set Intersection Size At Least Two 758. Bold Words in String 759. Employee Free Time 760. Find Anagram Mappings 761. Special Binary String 762. Prime Number of Set Bits in Binary Representation 763. Partition Labels 764. Largest Plus Sign 765. Couples Holding Hands 766. Toeplitz Matrix 767. Reorganize String 768. Max Chunks To Make Sorted II 769. Max Chunks To Make Sorted 770. Basic Calculator IV 771. Jewels and Stones 772. Basic Calculator III 773. Sliding Puzzle 774. Minimize Max Distance to Gas Station 775. Global and Local Inversions 776. Split BST 777. Swap Adjacent in LR String 778. Swim in Rising Water 779. K-th Symbol in Grammar 780. Reaching Points 781. Rabbits in Forest 782. Transform to Chessboard 783. Minimum Distance Between BST Nodes 784. Letter Case Permutation 785. Is Graph Bipartite? 786. K-th Smallest Prime Fraction 787. Cheapest Flights Within K Stops 788. Rotated Digits 789. Escape The Ghosts 790. Domino and Tromino Tiling 791. Custom Sort String 792. Number of Matching Subsequences 793. Preimage Size of Factorial Zeroes Function 794. Valid Tic-Tac-Toe State 795. Number of Subarrays with Bounded Maximum 796. Rotate String 797. All Paths From Source to Target 798. Smallest Rotation with Highest Score 799. Champagne Tower 800. Similar RGB Color 801. Minimum Swaps To Make Sequences Increasing 802. Find Eventual Safe States 803. Bricks Falling When Hit 804. Unique Morse Code Words 805. Split Array With Same Average 806. Number of Lines To Write String 807. Max Increase to Keep City Skyline 808. Soup Servings 809. Expressive Words 810. Chalkboard XOR Game 811. Subdomain Visit Count 812. Largest Triangle Area 813. Largest Sum of Averages 814. Binary Tree Pruning 815. Bus Routes 816. Ambiguous Coordinates 817. Linked List Components 818. Race Car 819. Most Common Word 820. Short Encoding of Words 821. Shortest Distance to a Character 822. Card Flipping Game 823. Binary Trees With Factors 824. Goat Latin 825. Friends Of Appropriate Ages 826. Most Profit Assigning Work 827. Making A Large Island 828. Count Unique Characters of All Substrings of a Given String 829. Consecutive Numbers Sum 830. Positions of Large Groups 831. Masking Personal Information 832. Flipping an Image 833. Find And Replace in String 834. Sum of Distances in Tree 835. Image Overlap 836. Rectangle Overlap 837. New 21 Game 838. Push Dominoes 839. Similar String Groups 840. Magic Squares In Grid 841. Keys and Rooms 842. Split Array into Fibonacci Sequence 843. Guess the Word 844. Backspace String Compare 845. Longest Mountain in Array 846. Hand of Straights 847. Shortest Path Visiting All Nodes 848. Shifting Letters 849. Maximize Distance to Closest Person 850. Rectangle Area II 851. Loud and Rich 852. Peak Index in a Mountain Array 853. Car Fleet 854. K-Similar Strings 855. Exam Room 856. Score of Parentheses 857. Minimum Cost to Hire K Workers 858. Mirror Reflection 859. Buddy Strings 860. Lemonade Change 861. Score After Flipping Matrix 862. Shortest Subarray with Sum at Least K 863. All Nodes Distance K in Binary Tree 864. Shortest Path to Get All Keys 865. Smallest Subtree with all the Deepest Nodes 866. Prime Palindrome 867. Transpose Matrix 868. Binary Gap 869. Reordered Power of 2 870. Advantage Shuffle 871. Minimum Number of Refueling Stops 872. Leaf-Similar Trees 873. Length of Longest Fibonacci Subsequence 874. Walking Robot Simulation 875. Koko Eating Bananas 876. Middle of the Linked List 877. Stone Game 878. Nth Magical Number 879. Profitable Schemes 880. Decoded String at Index 881. Boats to Save People 882. Reachable Nodes In Subdivided Graph 883. Projection Area of 3D Shapes 884. Uncommon Words from Two Sentences 885. Spiral Matrix III 886. Possible Bipartition 887. Super Egg Drop 888. Fair Candy Swap 889. Construct Binary Tree from Preorder and Postorder Traversal 890. Find and Replace Pattern 891. Sum of Subsequence Widths 892. Surface Area of 3D Shapes 893. Groups of Special-Equivalent Strings 894. All Possible Full Binary Trees 895. Maximum Frequency Stack 896. Monotonic Array 897. Increasing Order Search Tree 898. Bitwise ORs of Subarrays 899. Orderly Queue 900. RLE Iterator 901. Online Stock Span 902. Numbers At Most N Given Digit Set 903. Valid Permutations for DI Sequence 904. Fruit Into Baskets 905. Sort Array By Parity 906. Super Palindromes 907. Sum of Subarray Minimums 908. Smallest Range I 909. Snakes and Ladders 910. Smallest Range II 911. Online Election 912. Sort an Array 913. Cat and Mouse 914. X of a Kind in a Deck of Cards 915. Partition Array into Disjoint Intervals 916. Word Subsets 917. Reverse Only Letters 918. Maximum Sum Circular Subarray 919. Complete Binary Tree Inserter 920. Number of Music Playlists 921. Minimum Add to Make Parentheses Valid 922. Sort Array By Parity II 923. 3Sum With Multiplicity 924. Minimize Malware Spread 925. Long Pressed Name 926. Flip String to Monotone Increasing 927. Three Equal Parts 928. Minimize Malware Spread II 929. Unique Email Addresses 930. Binary Subarrays With Sum 931. Minimum Falling Path Sum 932. Beautiful Array 933. Number of Recent Calls 934. Shortest Bridge 935. Knight Dialer 936. Stamping The Sequence 937. Reorder Data in Log Files 938. Range Sum of BST 939. Minimum Area Rectangle 940. Distinct Subsequences II 941. Valid Mountain Array 942. DI String Match 943. Find the Shortest Superstring 944. Delete Columns to Make Sorted 945. Minimum Increment to Make Array Unique 946. Validate Stack Sequences 947. Most Stones Removed with Same Row or Column 948. Bag of Tokens 949. Largest Time for Given Digits 950. Reveal Cards In Increasing Order 951. Flip Equivalent Binary Trees 952. Largest Component Size by Common Factor 953. Verifying an Alien Dictionary 954. Array of Doubled Pairs 955. Delete Columns to Make Sorted II 956. Tallest Billboard 957. Prison Cells After N Days 958. Check Completeness of a Binary Tree 959. Regions Cut By Slashes 960. Delete Columns to Make Sorted III 961. N-Repeated Element in Size 2N Array 962. Maximum Width Ramp 963. Minimum Area Rectangle II 964. Least Operators to Express Number 965. Univalued Binary Tree 966. Vowel Spellchecker 967. Numbers With Same Consecutive Differences 968. Binary Tree Cameras 969. Pancake Sorting 970. Powerful Integers 971. Flip Binary Tree To Match Preorder Traversal 972. Equal Rational Numbers 973. K Closest Points to Origin 974. Subarray Sums Divisible by K 975. Odd Even Jump 976. Largest Perimeter Triangle 977. Squares of a Sorted Array 978. Longest Turbulent Subarray 979. Distribute Coins in Binary Tree 980. Unique Paths III 981. Time Based Key-Value Store 982. Triples with Bitwise AND Equal To Zero 983. Minimum Cost For Tickets 984. String Without AAA or BBB 985. Sum of Even Numbers After Queries 986. Interval List Intersections 987. Vertical Order Traversal of a Binary Tree 988. Smallest String Starting From Leaf 989. Add to Array-Form of Integer 990. Satisfiability of Equality Equations 991. Broken Calculator 992. Subarrays with K Different Integers 993. Cousins in Binary Tree 994. Rotting Oranges 995. Minimum Number of K Consecutive Bit Flips 996. Number of Squareful Arrays 997. Find the Town Judge 998. Maximum Binary Tree II 999. Available Captures for Rook 1000. Minimum Cost to Merge Stones 1001. Grid Illumination 1002. Find Common Characters 1003. Check If Word Is Valid After Substitutions 1004. Max Consecutive Ones III 1005. Maximize Sum Of Array After K Negations 1006. Clumsy Factorial 1007. Minimum Domino Rotations For Equal Row 1008. Construct Binary Search Tree from Preorder Traversal 1009. Complement of Base 10 Integer 1010. Pairs of Songs With Total Durations Divisible by 60 1011. Capacity To Ship Packages Within D Days 1012. Numbers With Repeated Digits 1013. Partition Array Into Three Parts With Equal Sum 1014. Best Sightseeing Pair 1015. Smallest Integer Divisible by K 1016. Binary String With Substrings Representing 1 To N 1017. Convert to Base -2 1018. Binary Prefix Divisible By 5 1019. Next Greater Node In Linked List 1020. Number of Enclaves 1021. Remove Outermost Parentheses 1022. Sum of Root To Leaf Binary Numbers 1023. Camelcase Matching 1024. Video Stitching 1025. Divisor Game 1026. Maximum Difference Between Node and Ancestor 1027. Longest Arithmetic Subsequence 1028. Recover a Tree From Preorder Traversal 1029. Two City Scheduling 1030. Matrix Cells in Distance Order 1031. Maximum Sum of Two Non-Overlapping Subarrays 1032. Stream of Characters 1033. Moving Stones Until Consecutive 1034. Coloring A Border 1035. Uncrossed Lines 1036. Escape a Large Maze 1037. Valid Boomerang 1038. Binary Search Tree to Greater Sum Tree 1039. Minimum Score Triangulation of Polygon 1040. Moving Stones Until Consecutive II 1041. Robot Bounded In Circle 1042. Flower Planting With No Adjacent 1043. Partition Array for Maximum Sum 1044. Longest Duplicate Substring 1045. Customers Who Bought All Products 1046. Last Stone Weight 1047. Remove All Adjacent Duplicates In String 1048. Longest String Chain 1049. Last Stone Weight II 1050. Actors and Directors Who Cooperated At Least Three Times 1051. Height Checker 1052. Grumpy Bookstore Owner 1053. Previous Permutation With One Swap 1054. Distant Barcodes 1055. Shortest Way to Form String 1056. Confusing Number 1057. Campus Bikes 1058. Minimize Rounding Error to Meet Target 1059. All Paths from Source Lead to Destination 1060. Missing Element in Sorted Array 1061. Lexicographically Smallest Equivalent String 1062. Longest Repeating Substring 1063. Number of Valid Subarrays 1064. Fixed Point 1065. Index Pairs of a String 1066. Campus Bikes II 1067. Digit Count in Range 1068. Product Sales Analysis I 1069. Product Sales Analysis II 1070. Product Sales Analysis III 1071. Greatest Common Divisor of Strings 1072. Flip Columns For Maximum Number of Equal Rows 1073. Adding Two Negabinary Numbers 1074. Number of Submatrices That Sum to Target 1075. Project Employees I 1076. Project Employees II 1077. Project Employees III 1078. Occurrences After Bigram 1079. Letter Tile Possibilities 1080. Insufficient Nodes in Root to Leaf Paths 1081. Smallest Subsequence of Distinct Characters 1082. Sales Analysis I 1083. Sales Analysis II 1084. Sales Analysis III 1085. Sum of Digits in the Minimum Number 1086. High Five 1087. Brace Expansion 1088. Confusing Number II 1089. Duplicate Zeros 1090. Largest Values From Labels 1091. Shortest Path in Binary Matrix 1092. Shortest Common Supersequence 1093. Statistics from a Large Sample 1094. Car Pooling 1095. Find in Mountain Array 1096. Brace Expansion II 1097. Game Play Analysis V 1098. Unpopular Books 1099. Two Sum Less Than K 1100. Find K-Length Substrings With No Repeated Characters 1101. The Earliest Moment When Everyone Become Friends 1102. Path With Maximum Minimum Value 1103. Distribute Candies to People 1104. Path In Zigzag Labelled Binary Tree 1105. Filling Bookcase Shelves 1106. Parsing A Boolean Expression 1107. New Users Daily Count 1108. Defanging an IP Address 1109. Corporate Flight Bookings 1110. Delete Nodes And Return Forest 1111. Maximum Nesting Depth of Two Valid Parentheses Strings 1112. Highest Grade For Each Student 1113. Reported Posts 1114. Print in Order 1115. Print FooBar Alternately 1116. Print Zero Even Odd 1117. Building H2O 1118. Number of Days in a Month 1119. Remove Vowels from a String 1120. Maximum Average Subtree 1121. Divide Array Into Increasing Sequences 1122. Relative Sort Array 1123. Lowest Common Ancestor of Deepest Leaves 1124. Longest Well-Performing Interval 1125. Smallest Sufficient Team 1126. Active Businesses 1127. User Purchase Platform 1128. Number of Equivalent Domino Pairs 1129. Shortest Path with Alternating Colors 1130. Minimum Cost Tree From Leaf Values 1131. Maximum of Absolute Value Expression 1132. Reported Posts II 1133. Largest Unique Number 1134. Armstrong Number 1135. Connecting Cities With Minimum Cost 1136. Parallel Courses 1137. N-th Tribonacci Number 1138. Alphabet Board Path 1139. Largest 1-Bordered Square 1140. Stone Game II 1141. User Activity for the Past 30 Days I 1142. User Activity for the Past 30 Days II 1143. Longest Common Subsequence 1144. Decrease Elements To Make Array Zigzag 1145. Binary Tree Coloring Game 1146. Snapshot Array 1147. Longest Chunked Palindrome Decomposition 1148. Article Views I 1149. Article Views II 1150. Check If a Number Is Majority Element in a Sorted Array 1151. Minimum Swaps to Group All 1's Together 1152. Analyze User Website Visit Pattern 1153. String Transforms Into Another String 1154. Day of the Year 1155. Number of Dice Rolls With Target Sum 1156. Swap For Longest Repeated Character Substring 1157. Online Majority Element In Subarray 1158. Market Analysis I 1159. Market Analysis II 1160. Find Words That Can Be Formed by Characters 1161. Maximum Level Sum of a Binary Tree 1162. As Far from Land as Possible 1163. Last Substring in Lexicographical Order 1164. Product Price at a Given Date 1165. Single-Row Keyboard 1166. Design File System 1167. Minimum Cost to Connect Sticks 1168. Optimize Water Distribution in a Village 1169. Invalid Transactions 1170. Compare Strings by Frequency of the Smallest Character 1171. Remove Zero Sum Consecutive Nodes from Linked List 1172. Dinner Plate Stacks 1173. Immediate Food Delivery I 1174. Immediate Food Delivery II 1175. Prime Arrangements 1176. Diet Plan Performance 1177. Can Make Palindrome from Substring 1178. Number of Valid Words for Each Puzzle 1179. Reformat Department Table 1180. Count Substrings with Only One Distinct Letter 1181. Before and After Puzzle 1182. Shortest Distance to Target Color 1183. Maximum Number of Ones 1184. Distance Between Bus Stops 1185. Day of the Week 1186. Maximum Subarray Sum with One Deletion 1187. Make Array Strictly Increasing 1188. Design Bounded Blocking Queue 1189. Maximum Number of Balloons 1190. Reverse Substrings Between Each Pair of Parentheses 1191. K-Concatenation Maximum Sum 1192. Critical Connections in a Network 1193. Monthly Transactions I 1194. Tournament Winners 1195. Fizz Buzz Multithreaded 1196. How Many Apples Can You Put into the Basket 1197. Minimum Knight Moves 1198. Find Smallest Common Element in All Rows 1199. Minimum Time to Build Blocks 1200. Minimum Absolute Difference 1201. Ugly Number III 1202. Smallest String With Swaps 1203. Sort Items by Groups Respecting Dependencies 1204. Last Person to Fit in the Bus 1205. Monthly Transactions II 1206. Design Skiplist 1207. Unique Number of Occurrences 1208. Get Equal Substrings Within Budget 1209. Remove All Adjacent Duplicates in String II 1210. Minimum Moves to Reach Target with Rotations 1211. Queries Quality and Percentage 1212. Team Scores in Football Tournament 1213. Intersection of Three Sorted Arrays 1214. Two Sum BSTs 1215. Stepping Numbers 1216. Valid Palindrome III 1217. Minimum Cost to Move Chips to The Same Position 1218. Longest Arithmetic Subsequence of Given Difference 1219. Path with Maximum Gold 1220. Count Vowels Permutation 1221. Split a String in Balanced Strings 1222. Queens That Can Attack the King 1223. Dice Roll Simulation 1224. Maximum Equal Frequency 1225. Report Contiguous Dates 1226. The Dining Philosophers 1227. Airplane Seat Assignment Probability 1228. Missing Number In Arithmetic Progression 1229. Meeting Scheduler 1230. Toss Strange Coins 1231. Divide Chocolate 1232. Check If It Is a Straight Line 1233. Remove Sub-Folders from the Filesystem 1234. Replace the Substring for Balanced String 1235. Maximum Profit in Job Scheduling 1236. Web Crawler 1237. Find Positive Integer Solution for a Given Equation 1238. Circular Permutation in Binary Representation 1239. Maximum Length of a Concatenated String with Unique Characters 1240. Tiling a Rectangle with the Fewest Squares 1241. Number of Comments per Post 1242. Web Crawler Multithreaded 1243. Array Transformation 1244. Design A Leaderboard 1245. Tree Diameter 1246. Palindrome Removal 1247. Minimum Swaps to Make Strings Equal 1248. Count Number of Nice Subarrays 1249. Minimum Remove to Make Valid Parentheses 1250. Check If It Is a Good Array 1251. Average Selling Price 1252. Cells with Odd Values in a Matrix 1253. Reconstruct a 2-Row Binary Matrix 1254. Number of Closed Islands 1255. Maximum Score Words Formed by Letters 1256. Encode Number 1257. Smallest Common Region 1258. Synonymous Sentences 1259. Handshakes That Don't Cross 1260. Shift 2D Grid 1261. Find Elements in a Contaminated Binary Tree 1262. Greatest Sum Divisible by Three 1263. Minimum Moves to Move a Box to Their Target Location 1264. Page Recommendations 1265. Print Immutable Linked List in Reverse 1266. Minimum Time Visiting All Points 1267. Count Servers that Communicate 1268. Search Suggestions System 1269. Number of Ways to Stay in the Same Place After Some Steps 1270. All People Report to the Given Manager 1271. Hexspeak 1272. Remove Interval 1273. Delete Tree Nodes 1274. Number of Ships in a Rectangle 1275. Find Winner on a Tic Tac Toe Game 1276. Number of Burgers with No Waste of Ingredients 1277. Count Square Submatrices with All Ones 1278. Palindrome Partitioning III 1279. Traffic Light Controlled Intersection 1280. Students and Examinations 1281. Subtract the Product and Sum of Digits of an Integer 1282. Group the People Given the Group Size They Belong To 1283. Find the Smallest Divisor Given a Threshold 1284. Minimum Number of Flips to Convert Binary Matrix to Zero Matrix 1285. Find the Start and End Number of Continuous Ranges 1286. Iterator for Combination 1287. Element Appearing More Than 25% In Sorted Array 1288. Remove Covered Intervals 1289. Minimum Falling Path Sum II 1290. Convert Binary Number in a Linked List to Integer 1291. Sequential Digits 1292. Maximum Side Length of a Square with Sum Less than or Equal to Threshold 1293. Shortest Path in a Grid with Obstacles Elimination 1294. Weather Type in Each Country 1295. Find Numbers with Even Number of Digits 1296. Divide Array in Sets of K Consecutive Numbers 1297. Maximum Number of Occurrences of a Substring 1298. Maximum Candies You Can Get from Boxes 1299. Replace Elements with Greatest Element on Right Side 1300. Sum of Mutated Array Closest to Target 1301. Number of Paths with Max Score 1302. Deepest Leaves Sum 1303. Find the Team Size 1304. Find N Unique Integers Sum up to Zero 1305. All Elements in Two Binary Search Trees 1306. Jump Game III 1307. Verbal Arithmetic Puzzle 1308. Running Total for Different Genders 1309. Decrypt String from Alphabet to Integer Mapping 1310. XOR Queries of a Subarray 1311. Get Watched Videos by Your Friends 1312. Minimum Insertion Steps to Make a String Palindrome 1313. Decompress Run-Length Encoded List 1314. Matrix Block Sum 1315. Sum of Nodes with Even-Valued Grandparent 1316. Distinct Echo Substrings 1317. Convert Integer to the Sum of Two No-Zero Integers 1318. Minimum Flips to Make a OR b Equal to c 1319. Number of Operations to Make Network Connected 1320. Minimum Distance to Type a Word Using Two Fingers 1321. Restaurant Growth 1322. Ads Performance 1323. Maximum 69 Number 1324. Print Words Vertically 1325. Delete Leaves With a Given Value 1326. Minimum Number of Taps to Open to Water a Garden 1327. List the Products Ordered in a Period 1328. Break a Palindrome 1329. Sort the Matrix Diagonally 1330. Reverse Subarray To Maximize Array Value 1331. Rank Transform of an Array 1332. Remove Palindromic Subsequences 1333. Filter Restaurants by Vegan-Friendly, Price and Distance 1334. Find the City With the Smallest Number of Neighbors at a Threshold Distance 1335. Minimum Difficulty of a Job Schedule 1336. Number of Transactions per Visit 1337. The K Weakest Rows in a Matrix 1338. Reduce Array Size to The Half 1339. Maximum Product of Splitted Binary Tree 1340. Jump Game V 1341. Movie Rating 1342. Number of Steps to Reduce a Number to Zero 1343. Number of Sub-arrays of Size K and Average Greater than or Equal to Threshold 1344. Angle Between Hands of a Clock 1345. Jump Game IV 1346. Check If N and Its Double Exist 1347. Minimum Number of Steps to Make Two Strings Anagram 1348. Tweet Counts Per Frequency 1349. Maximum Students Taking Exam 1350. Students With Invalid Departments 1351. Count Negative Numbers in a Sorted Matrix 1352. Product of the Last K Numbers 1353. Maximum Number of Events That Can Be Attended 1354. Construct Target Array With Multiple Sums 1355. Activity Participants 1356. Sort Integers by The Number of 1 Bits 1357. Apply Discount Every n Orders 1358. Number of Substrings Containing All Three Characters 1359. Count All Valid Pickup and Delivery Options 1360. Number of Days Between Two Dates 1361. Validate Binary Tree Nodes 1362. Closest Divisors 1363. Largest Multiple of Three 1364. Number of Trusted Contacts of a Customer 1365. How Many Numbers Are Smaller Than the Current Number 1366. Rank Teams by Votes 1367. Linked List in Binary Tree 1368. Minimum Cost to Make at Least One Valid Path in a Grid 1369. Get the Second Most Recent Activity 1370. Increasing Decreasing String 1371. Find the Longest Substring Containing Vowels in Even Counts 1372. Longest ZigZag Path in a Binary Tree 1373. Maximum Sum BST in Binary Tree 1374. Generate a String With Characters That Have Odd Counts 1375. Number of Times Binary String Is Prefix-Aligned 1376. Time Needed to Inform All Employees 1377. Frog Position After T Seconds 1378. Replace Employee ID With The Unique Identifier 1379. Find a Corresponding Node of a Binary Tree in a Clone of That Tree 1380. Lucky Numbers in a Matrix 1381. Design a Stack With Increment Operation 1382. Balance a Binary Search Tree 1383. Maximum Performance of a Team 1384. Total Sales Amount by Year 1385. Find the Distance Value Between Two Arrays 1386. Cinema Seat Allocation 1387. Sort Integers by The Power Value 1388. Pizza With 3n Slices 1389. Create Target Array in the Given Order 1390. Four Divisors 1391. Check if There is a Valid Path in a Grid 1392. Longest Happy Prefix 1393. Capital Gain/Loss 1394. Find Lucky Integer in an Array 1395. Count Number of Teams 1396. Design Underground System 1397. Find All Good Strings 1398. Customers Who Bought Products A and B but Not C 1399. Count Largest Group 1400. Construct K Palindrome Strings 1401. Circle and Rectangle Overlapping 1402. Reducing Dishes 1403. Minimum Subsequence in Non-Increasing Order 1404. Number of Steps to Reduce a Number in Binary Representation to One 1405. Longest Happy String 1406. Stone Game III 1407. Top Travellers 1408. String Matching in an Array 1409. Queries on a Permutation With Key 1410. HTML Entity Parser 1411. Number of Ways to Paint N × 3 Grid 1412. Find the Quiet Students in All Exams 1413. Minimum Value to Get Positive Step by Step Sum 1414. Find the Minimum Number of Fibonacci Numbers Whose Sum Is K 1415. The k-th Lexicographical String of All Happy Strings of Length n 1416. Restore The Array 1417. Reformat The String 1418. Display Table of Food Orders in a Restaurant 1419. Minimum Number of Frogs Croaking 1420. Build Array Where You Can Find The Maximum Exactly K Comparisons 1421. NPV Queries 1422. Maximum Score After Splitting a String 1423. Maximum Points You Can Obtain from Cards 1424. Diagonal Traverse II 1425. Constrained Subsequence Sum 1426. Counting Elements 1427. Perform String Shifts 1428. Leftmost Column with at Least a One 1429. First Unique Number 1430. Check If a String Is a Valid Sequence from Root to Leaves Path in a Binary Tree 1431. Kids With the Greatest Number of Candies 1432. Max Difference You Can Get From Changing an Integer 1433. Check If a String Can Break Another String 1434. Number of Ways to Wear Different Hats to Each Other 1435. Create a Session Bar Chart 1436. Destination City 1437. Check If All 1's Are at Least Length K Places Away 1438. Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit 1439. Find the Kth Smallest Sum of a Matrix With Sorted Rows 1440. Evaluate Boolean Expression 1441. Build an Array With Stack Operations 1442. Count Triplets That Can Form Two Arrays of Equal XOR 1443. Minimum Time to Collect All Apples in a Tree 1444. Number of Ways of Cutting a Pizza 1445. Apples & Oranges 1446. Consecutive Characters 1447. Simplified Fractions 1448. Count Good Nodes in Binary Tree 1449. Form Largest Integer With Digits That Add up to Target 1450. Number of Students Doing Homework at a Given Time 1451. Rearrange Words in a Sentence 1452. People Whose List of Favorite Companies Is Not a Subset of Another List 1453. Maximum Number of Darts Inside of a Circular Dartboard 1454. Active Users 1455. Check If a Word Occurs As a Prefix of Any Word in a Sentence 1456. Maximum Number of Vowels in a Substring of Given Length 1457. Pseudo-Palindromic Paths in a Binary Tree 1458. Max Dot Product of Two Subsequences 1459. Rectangles Area 1460. Make Two Arrays Equal by Reversing Subarrays 1461. Check If a String Contains All Binary Codes of Size K 1462. Course Schedule IV 1463. Cherry Pickup II 1464. Maximum Product of Two Elements in an Array 1465. Maximum Area of a Piece of Cake After Horizontal and Vertical Cuts 1466. Reorder Routes to Make All Paths Lead to the City Zero 1467. Probability of a Two Boxes Having The Same Number of Distinct Balls 1468. Calculate Salaries 1469. Find All The Lonely Nodes 1470. Shuffle the Array 1471. The k Strongest Values in an Array 1472. Design Browser History 1473. Paint House III 1474. Delete N Nodes After M Nodes of a Linked List 1475. Final Prices With a Special Discount in a Shop 1476. Subrectangle Queries 1477. Find Two Non-overlapping Sub-arrays Each With Target Sum 1478. Allocate Mailboxes 1479. Sales by Day of the Week 1480. Running Sum of 1d Array 1481. Least Number of Unique Integers after K Removals 1482. Minimum Number of Days to Make m Bouquets 1483. Kth Ancestor of a Tree Node 1484. Group Sold Products By The Date 1485. Clone Binary Tree With Random Pointer 1486. XOR Operation in an Array 1487. Making File Names Unique 1488. Avoid Flood in The City 1489. Find Critical and Pseudo-Critical Edges in Minimum Spanning Tree 1490. Clone N-ary Tree 1491. Average Salary Excluding the Minimum and Maximum Salary 1492. The kth Factor of n 1493. Longest Subarray of 1's After Deleting One Element 1494. Parallel Courses II 1495. Friendly Movies Streamed Last Month 1496. Path Crossing 1497. Check If Array Pairs Are Divisible by k 1498. Number of Subsequences That Satisfy the Given Sum Condition 1499. Max Value of Equation 1500. Design a File Sharing System 1501. Countries You Can Safely Invest In 1502. Can Make Arithmetic Progression From Sequence 1503. Last Moment Before All Ants Fall Out of a Plank 1504. Count Submatrices With All Ones 1505. Minimum Possible Integer After at Most K Adjacent Swaps On Digits 1506. Find Root of N-Ary Tree 1507. Reformat Date 1508. Range Sum of Sorted Subarray Sums 1509. Minimum Difference Between Largest and Smallest Value in Three Moves 1510. Stone Game IV 1511. Customer Order Frequency 1512. Number of Good Pairs 1513. Number of Substrings With Only 1s 1514. Path with Maximum Probability 1515. Best Position for a Service Centre 1516. Move Sub-Tree of N-Ary Tree 1517. Find Users With Valid E-Mails 1518. Water Bottles 1519. Number of Nodes in the Sub-Tree With the Same Label 1520. Maximum Number of Non-Overlapping Substrings 1521. Find a Value of a Mysterious Function Closest to Target 1522. Diameter of N-Ary Tree 1523. Count Odd Numbers in an Interval Range 1524. Number of Sub-arrays With Odd Sum 1525. Number of Good Ways to Split a String 1526. Minimum Number of Increments on Subarrays to Form a Target Array 1527. Patients With a Condition 1528. Shuffle String 1529. Minimum Suffix Flips 1530. Number of Good Leaf Nodes Pairs 1531. String Compression II 1532. The Most Recent Three Orders 1533. Find the Index of the Large Integer 1534. Count Good Triplets 1535. Find the Winner of an Array Game 1536. Minimum Swaps to Arrange a Binary Grid 1537. Get the Maximum Score 1538. Guess the Majority in a Hidden Array 1539. Kth Missing Positive Number 1540. Can Convert String in K Moves 1541. Minimum Insertions to Balance a Parentheses String 1542. Find Longest Awesome Substring 1543. Fix Product Name Format 1544. Make The String Great 1545. Find Kth Bit in Nth Binary String 1546. Maximum Number of Non-Overlapping Subarrays With Sum Equals Target 1547. Minimum Cost to Cut a Stick 1548. The Most Similar Path in a Graph 1549. The Most Recent Orders for Each Product 1550. Three Consecutive Odds 1551. Minimum Operations to Make Array Equal 1552. Magnetic Force Between Two Balls 1553. Minimum Number of Days to Eat N Oranges 1554. Strings Differ by One Character 1555. Bank Account Summary 1556. Thousand Separator 1557. Minimum Number of Vertices to Reach All Nodes 1558. Minimum Numbers of Function Calls to Make Target Array 1559. Detect Cycles in 2D Grid 1560. Most Visited Sector in a Circular Track 1561. Maximum Number of Coins You Can Get 1562. Find Latest Group of Size M 1563. Stone Game V 1564. Put Boxes Into the Warehouse I 1565. Unique Orders and Customers Per Month 1566. Detect Pattern of Length M Repeated K or More Times 1567. Maximum Length of Subarray With Positive Product 1568. Minimum Number of Days to Disconnect Island 1569. Number of Ways to Reorder Array to Get Same BST 1570. Dot Product of Two Sparse Vectors 1571. Warehouse Manager 1572. Matrix Diagonal Sum 1573. Number of Ways to Split a String 1574. Shortest Subarray to be Removed to Make Array Sorted 1575. Count All Possible Routes 1576. Replace All ?'s to Avoid Consecutive Repeating Characters 1577. Number of Ways Where Square of Number Is Equal to Product of Two Numbers 1578. Minimum Time to Make Rope Colorful 1579. Remove Max Number of Edges to Keep Graph Fully Traversable 1580. Put Boxes Into the Warehouse II 1581. Customer Who Visited but Did Not Make Any Transactions 1582. Special Positions in a Binary Matrix 1583. Count Unhappy Friends 1584. Min Cost to Connect All Points 1585. Check If String Is Transformable With Substring Sort Operations 1586. Binary Search Tree Iterator II 1587. Bank Account Summary II 1588. Sum of All Odd Length Subarrays 1589. Maximum Sum Obtained of Any Permutation 1590. Make Sum Divisible by P 1591. Strange Printer II 1592. Rearrange Spaces Between Words 1593. Split a String Into the Max Number of Unique Substrings 1594. Maximum Non Negative Product in a Matrix 1595. Minimum Cost to Connect Two Groups of Points 1596. The Most Frequently Ordered Products for Each Customer 1597. Build Binary Expression Tree From Infix Expression 1598. Crawler Log Folder 1599. Maximum Profit of Operating a Centennial Wheel 1600. Throne Inheritance 1601. Maximum Number of Achievable Transfer Requests 1602. Find Nearest Right Node in Binary Tree 1603. Design Parking System 1604. Alert Using Same Key-Card Three or More Times in a One Hour Period 1605. Find Valid Matrix Given Row and Column Sums 1606. Find Servers That Handled Most Number of Requests 1607. Sellers With No Sales 1608. Special Array With X Elements Greater Than or Equal X 1609. Even Odd Tree 1610. Maximum Number of Visible Points 1611. Minimum One Bit Operations to Make Integers Zero 1612. Check If Two Expression Trees are Equivalent 1613. Find the Missing IDs 1614. Maximum Nesting Depth of the Parentheses 1615. Maximal Network Rank 1616. Split Two Strings to Make Palindrome 1617. Count Subtrees With Max Distance Between Cities 1618. Maximum Font to Fit a Sentence in a Screen 1619. Mean of Array After Removing Some Elements 1620. Coordinate With Maximum Network Quality 1621. Number of Sets of K Non-Overlapping Line Segments 1622. Fancy Sequence 1623. All Valid Triplets That Can Represent a Country 1624. Largest Substring Between Two Equal Characters 1625. Lexicographically Smallest String After Applying Operations 1626. Best Team With No Conflicts 1627. Graph Connectivity With Threshold 1628. Design an Expression Tree With Evaluate Function 1629. Slowest Key 1630. Arithmetic Subarrays 1631. Path With Minimum Effort 1632. Rank Transform of a Matrix 1633. Percentage of Users Attended a Contest 1634. Add Two Polynomials Represented as Linked Lists 1635. Hopper Company Queries I 1636. Sort Array by Increasing Frequency 1637. Widest Vertical Area Between Two Points Containing No Points 1638. Count Substrings That Differ by One Character 1639. Number of Ways to Form a Target String Given a Dictionary 1640. Check Array Formation Through Concatenation 1641. Count Sorted Vowel Strings 1642. Furthest Building You Can Reach 1643. Kth Smallest Instructions 1644. Lowest Common Ancestor of a Binary Tree II 1645. Hopper Company Queries II 1646. Get Maximum in Generated Array 1647. Minimum Deletions to Make Character Frequencies Unique 1648. Sell Diminishing-Valued Colored Balls 1649. Create Sorted Array through Instructions 1650. Lowest Common Ancestor of a Binary Tree III 1651. Hopper Company Queries III 1652. Defuse the Bomb 1653. Minimum Deletions to Make String Balanced 1654. Minimum Jumps to Reach Home 1655. Distribute Repeating Integers 1656. Design an Ordered Stream 1657. Determine if Two Strings Are Close 1658. Minimum Operations to Reduce X to Zero 1659. Maximize Grid Happiness 1660. Correct a Binary Tree 1661. Average Time of Process per Machine 1662. Check If Two String Arrays are Equivalent 1663. Smallest String With A Given Numeric Value 1664. Ways to Make a Fair Array 1665. Minimum Initial Energy to Finish Tasks 1666. Change the Root of a Binary Tree 1667. Fix Names in a Table 1668. Maximum Repeating Substring 1669. Merge In Between Linked Lists 1670. Design Front Middle Back Queue 1671. Minimum Number of Removals to Make Mountain Array 1672. Richest Customer Wealth 1673. Find the Most Competitive Subsequence 1674. Minimum Moves to Make Array Complementary 1675. Minimize Deviation in Array 1676. Lowest Common Ancestor of a Binary Tree IV 1677. Product's Worth Over Invoices 1678. Goal Parser Interpretation 1679. Max Number of K-Sum Pairs 1680. Concatenation of Consecutive Binary Numbers 1681. Minimum Incompatibility 1682. Longest Palindromic Subsequence II 1683. Invalid Tweets 1684. Count the Number of Consistent Strings 1685. Sum of Absolute Differences in a Sorted Array 1686. Stone Game VI 1687. Delivering Boxes from Storage to Ports 1688. Count of Matches in Tournament 1689. Partitioning Into Minimum Number Of Deci-Binary Numbers 1690. Stone Game VII 1691. Maximum Height by Stacking Cuboids 1692. Count Ways to Distribute Candies 1693. Daily Leads and Partners 1694. Reformat Phone Number 1695. Maximum Erasure Value 1696. Jump Game VI 1697. Checking Existence of Edge Length Limited Paths 1698. Number of Distinct Substrings in a String 1699. Number of Calls Between Two Persons 1700. Number of Students Unable to Eat Lunch 1701. Average Waiting Time 1702. Maximum Binary String After Change 1703. Minimum Adjacent Swaps for K Consecutive Ones 1704. Determine if String Halves Are Alike 1705. Maximum Number of Eaten Apples 1706. Where Will the Ball Fall 1707. Maximum XOR With an Element From Array 1708. Largest Subarray Length K 1709. Biggest Window Between Visits 1710. Maximum Units on a Truck 1711. Count Good Meals 1712. Ways to Split Array Into Three Subarrays 1713. Minimum Operations to Make a Subsequence 1714. Sum Of Special Evenly-Spaced Elements In Array 1715. Count Apples and Oranges 1716. Calculate Money in Leetcode Bank 1717. Maximum Score From Removing Substrings 1718. Construct the Lexicographically Largest Valid Sequence 1719. Number Of Ways To Reconstruct A Tree 1720. Decode XORed Array 1721. Swapping Nodes in a Linked List 1722. Minimize Hamming Distance After Swap Operations 1723. Find Minimum Time to Finish All Jobs 1724. Checking Existence of Edge Length Limited Paths II 1725. Number Of Rectangles That Can Form The Largest Square 1726. Tuple with Same Product 1727. Largest Submatrix With Rearrangements 1728. Cat and Mouse II 1729. Find Followers Count 1730. Shortest Path to Get Food 1731. The Number of Employees Which Report to Each Employee 1732. Find the Highest Altitude 1733. Minimum Number of People to Teach 1734. Decode XORed Permutation 1735. Count Ways to Make Array With Product 1736. Latest Time by Replacing Hidden Digits 1737. Change Minimum Characters to Satisfy One of Three Conditions 1738. Find Kth Largest XOR Coordinate Value 1739. Building Boxes 1740. Find Distance in a Binary Tree 1741. Find Total Time Spent by Each Employee 1742. Maximum Number of Balls in a Box 1743. Restore the Array From Adjacent Pairs 1744. Can You Eat Your Favorite Candy on Your Favorite Day? 1745. Palindrome Partitioning IV 1746. Maximum Subarray Sum After One Operation 1747. Leetflex Banned Accounts 1748. Sum of Unique Elements 1749. Maximum Absolute Sum of Any Subarray 1750. Minimum Length of String After Deleting Similar Ends 1751. Maximum Number of Events That Can Be Attended II 1752. Check if Array Is Sorted and Rotated 1753. Maximum Score From Removing Stones 1754. Largest Merge Of Two Strings 1755. Closest Subsequence Sum 1756. Design Most Recently Used Queue 1757. Recyclable and Low Fat Products 1758. Minimum Changes To Make Alternating Binary String 1759. Count Number of Homogenous Substrings 1760. Minimum Limit of Balls in a Bag 1761. Minimum Degree of a Connected Trio in a Graph 1762. Buildings With an Ocean View 1763. Longest Nice Substring 1764. Form Array by Concatenating Subarrays of Another Array 1765. Map of Highest Peak 1766. Tree of Coprimes 1767. Find the Subtasks That Did Not Execute 1768. Merge Strings Alternately 1769. Minimum Number of Operations to Move All Balls to Each Box 1770. Maximum Score from Performing Multiplication Operations 1771. Maximize Palindrome Length From Subsequences 1772. Sort Features by Popularity 1773. Count Items Matching a Rule 1774. Closest Dessert Cost 1775. Equal Sum Arrays With Minimum Number of Operations 1776. Car Fleet II 1777. Product's Price for Each Store 1778. Shortest Path in a Hidden Grid 1779. Find Nearest Point That Has the Same X or Y Coordinate 1780. Check if Number is a Sum of Powers of Three 1781. Sum of Beauty of All Substrings 1782. Count Pairs Of Nodes 1783. Grand Slam Titles 1784. Check if Binary String Has at Most One Segment of Ones 1785. Minimum Elements to Add to Form a Given Sum 1786. Number of Restricted Paths From First to Last Node 1787. Make the XOR of All Segments Equal to Zero 1788. Maximize the Beauty of the Garden 1789. Primary Department for Each Employee 1790. Check if One String Swap Can Make Strings Equal 1791. Find Center of Star Graph 1792. Maximum Average Pass Ratio 1793. Maximum Score of a Good Subarray 1794. Count Pairs of Equal Substrings With Minimum Difference 1795. Rearrange Products Table 1796. Second Largest Digit in a String 1797. Design Authentication Manager 1798. Maximum Number of Consecutive Values You Can Make 1799. Maximize Score After N Operations 1800. Maximum Ascending Subarray Sum 1801. Number of Orders in the Backlog 1802. Maximum Value at a Given Index in a Bounded Array 1803. Count Pairs With XOR in a Range 1804. Implement Trie II (Prefix Tree) 1805. Number of Different Integers in a String 1806. Minimum Number of Operations to Reinitialize a Permutation 1807. Evaluate the Bracket Pairs of a String 1808. Maximize Number of Nice Divisors 1809. Ad-Free Sessions 1810. Minimum Path Cost in a Hidden Grid 1811. Find Interview Candidates 1812. Determine Color of a Chessboard Square 1813. Sentence Similarity III 1814. Count Nice Pairs in an Array 1815. Maximum Number of Groups Getting Fresh Donuts 1816. Truncate Sentence 1817. Finding the Users Active Minutes 1818. Minimum Absolute Sum Difference 1819. Number of Different Subsequences GCDs 1820. Maximum Number of Accepted Invitations 1821. Find Customers With Positive Revenue this Year 1822. Sign of the Product of an Array 1823. Find the Winner of the Circular Game 1824. Minimum Sideway Jumps 1825. Finding MK Average 1826. Faulty Sensor 1827. Minimum Operations to Make the Array Increasing 1828. Queries on Number of Points Inside a Circle 1829. Maximum XOR for Each Query 1830. Minimum Number of Operations to Make String Sorted 1831. Maximum Transaction Each Day 1832. Check if the Sentence Is Pangram 1833. Maximum Ice Cream Bars 1834. Single-Threaded CPU 1835. Find XOR Sum of All Pairs Bitwise AND 1836. Remove Duplicates From an Unsorted Linked List 1837. Sum of Digits in Base K 1838. Frequency of the Most Frequent Element 1839. Longest Substring Of All Vowels in Order 1840. Maximum Building Height 1841. League Statistics 1842. Next Palindrome Using Same Digits 1843. Suspicious Bank Accounts 1844. Replace All Digits with Characters 1845. Seat Reservation Manager 1846. Maximum Element After Decreasing and Rearranging 1847. Closest Room 1848. Minimum Distance to the Target Element 1849. Splitting a String Into Descending Consecutive Values 1850. Minimum Adjacent Swaps to Reach the Kth Smallest Number 1851. Minimum Interval to Include Each Query 1852. Distinct Numbers in Each Subarray 1853. Convert Date Format 1854. Maximum Population Year 1855. Maximum Distance Between a Pair of Values 1856. Maximum Subarray Min-Product 1857. Largest Color Value in a Directed Graph 1858. Longest Word With All Prefixes 1859. Sorting the Sentence 1860. Incremental Memory Leak 1861. Rotating the Box 1862. Sum of Floored Pairs 1863. Sum of All Subset XOR Totals 1864. Minimum Number of Swaps to Make the Binary String Alternating 1865. Finding Pairs With a Certain Sum 1866. Number of Ways to Rearrange Sticks With K Sticks Visible 1867. Orders With Maximum Quantity Above Average 1868. Product of Two Run-Length Encoded Arrays 1869. Longer Contiguous Segments of Ones than Zeros 1870. Minimum Speed to Arrive on Time 1871. Jump Game VII 1872. Stone Game VIII 1873. Calculate Special Bonus 1874. Minimize Product Sum of Two Arrays 1875. Group Employees of the Same Salary 1876. Substrings of Size Three with Distinct Characters 1877. Minimize Maximum Pair Sum in Array 1878. Get Biggest Three Rhombus Sums in a Grid 1879. Minimum XOR Sum of Two Arrays 1880. Check if Word Equals Summation of Two Words 1881. Maximum Value after Insertion 1882. Process Tasks Using Servers 1883. Minimum Skips to Arrive at Meeting On Time 1884. Egg Drop With 2 Eggs and N Floors 1885. Count Pairs in Two Arrays 1886. Determine Whether Matrix Can Be Obtained By Rotation 1887. Reduction Operations to Make the Array Elements Equal 1888. Minimum Number of Flips to Make the Binary String Alternating 1889. Minimum Space Wasted From Packaging 1890. The Latest Login in 2020 1891. Cutting Ribbons 1892. Page Recommendations II 1893. Check if All the Integers in a Range Are Covered 1894. Find the Student that Will Replace the Chalk 1895. Largest Magic Square 1896. Minimum Cost to Change the Final Value of Expression 1897. Redistribute Characters to Make All Strings Equal 1898. Maximum Number of Removable Characters 1899. Merge Triplets to Form Target Triplet 1900. The Earliest and Latest Rounds Where Players Compete 1901. Find a Peak Element II 1902. Depth of BST Given Insertion Order 1903. Largest Odd Number in String 1904. The Number of Full Rounds You Have Played 1905. Count Sub Islands 1906. Minimum Absolute Difference Queries 1907. Count Salary Categories 1908. Game of Nim 1909. Remove One Element to Make the Array Strictly Increasing 1910. Remove All Occurrences of a Substring 1911. Maximum Alternating Subsequence Sum 1912. Design Movie Rental System 1913. Maximum Product Difference Between Two Pairs 1914. Cyclically Rotating a Grid 1915. Number of Wonderful Substrings 1916. Count Ways to Build Rooms in an Ant Colony 1917. Leetcodify Friends Recommendations 1918. Kth Smallest Subarray Sum 1919. Leetcodify Similar Friends 1920. Build Array from Permutation 1921. Eliminate Maximum Number of Monsters 1922. Count Good Numbers 1923. Longest Common Subpath 1924. Erect the Fence II 1925. Count Square Sum Triples 1926. Nearest Exit from Entrance in Maze 1927. Sum Game 1928. Minimum Cost to Reach Destination in Time 1929. Concatenation of Array 1930. Unique Length-3 Palindromic Subsequences 1931. Painting a Grid With Three Different Colors 1932. Merge BSTs to Create Single BST 1933. Check if String Is Decomposable Into Value-Equal Substrings 1934. Confirmation Rate 1935. Maximum Number of Words You Can Type 1936. Add Minimum Number of Rungs 1937. Maximum Number of Points with Cost 1938. Maximum Genetic Difference Query 1939. Users That Actively Request Confirmation Messages 1940. Longest Common Subsequence Between Sorted Arrays 1941. Check if All Characters Have Equal Number of Occurrences 1942. The Number of the Smallest Unoccupied Chair 1943. Describe the Painting 1944. Number of Visible People in a Queue 1945. Sum of Digits of String After Convert 1946. Largest Number After Mutating Substring 1947. Maximum Compatibility Score Sum 1948. Delete Duplicate Folders in System 1949. Strong Friendship 1950. Maximum of Minimum Values in All Subarrays 1951. All the Pairs With the Maximum Number of Common Followers 1952. Three Divisors 1953. Maximum Number of Weeks for Which You Can Work 1954. Minimum Garden Perimeter to Collect Enough Apples 1955. Count Number of Special Subsequences 1956. Minimum Time For K Virus Variants to Spread 1957. Delete Characters to Make Fancy String 1958. Check if Move is Legal 1959. Minimum Total Space Wasted With K Resizing Operations 1960. Maximum Product of the Length of Two Palindromic Substrings 1961. Check If String Is a Prefix of Array 1962. Remove Stones to Minimize the Total 1963. Minimum Number of Swaps to Make the String Balanced 1964. Find the Longest Valid Obstacle Course at Each Position 1965. Employees With Missing Information 1966. Binary Searchable Numbers in an Unsorted Array 1967. Number of Strings That Appear as Substrings in Word 1968. Array With Elements Not Equal to Average of Neighbors 1969. Minimum Non-Zero Product of the Array Elements 1970. Last Day Where You Can Still Cross 1971. Find if Path Exists in Graph 1972. First and Last Call On the Same Day 1973. Count Nodes Equal to Sum of Descendants 1974. Minimum Time to Type Word Using Special Typewriter 1975. Maximum Matrix Sum 1976. Number of Ways to Arrive at Destination 1977. Number of Ways to Separate Numbers 1978. Employees Whose Manager Left the Company 1979. Find Greatest Common Divisor of Array 1980. Find Unique Binary String 1981. Minimize the Difference Between Target and Chosen Elements 1982. Find Array Given Subset Sums 1983. Widest Pair of Indices With Equal Range Sum 1984. Minimum Difference Between Highest and Lowest of K Scores 1985. Find the Kth Largest Integer in the Array 1986. Minimum Number of Work Sessions to Finish the Tasks 1987. Number of Unique Good Subsequences 1988. Find Cutoff Score for Each School 1989. Maximum Number of People That Can Be Caught in Tag 1990. Count the Number of Experiments 1991. Find the Middle Index in Array 1992. Find All Groups of Farmland 1993. Operations on Tree 1994. The Number of Good Subsets 1995. Count Special Quadruplets 1996. The Number of Weak Characters in the Game 1997. First Day Where You Have Been in All the Rooms 1998. GCD Sort of an Array 1999. Smallest Greater Multiple Made of Two Digits 2000. Reverse Prefix of Word 2001. Number of Pairs of Interchangeable Rectangles 2002. Maximum Product of the Length of Two Palindromic Subsequences 2003. Smallest Missing Genetic Value in Each Subtree 2004. The Number of Seniors and Juniors to Join the Company 2005. Subtree Removal Game with Fibonacci Tree 2006. Count Number of Pairs With Absolute Difference K 2007. Find Original Array From Doubled Array 2008. Maximum Earnings From Taxi 2009. Minimum Number of Operations to Make Array Continuous 2010. The Number of Seniors and Juniors to Join the Company II 2011. Final Value of Variable After Performing Operations 2012. Sum of Beauty in the Array 2013. Detect Squares 2014. Longest Subsequence Repeated k Times 2015. Average Height of Buildings in Each Segment 2016. Maximum Difference Between Increasing Elements 2017. Grid Game 2018. Check if Word Can Be Placed In Crossword 2019. The Score of Students Solving Math Expression 2020. Number of Accounts That Did Not Stream 2021. Brightest Position on Street 2022. Convert 1D Array Into 2D Array 2023. Number of Pairs of Strings With Concatenation Equal to Target 2024. Maximize the Confusion of an Exam 2025. Maximum Number of Ways to Partition an Array 2026. Low-Quality Problems 2027. Minimum Moves to Convert String 2028. Find Missing Observations 2029. Stone Game IX 2030. Smallest K-Length Subsequence With Occurrences of a Letter 2031. Count Subarrays With More Ones Than Zeros 2032. Two Out of Three 2033. Minimum Operations to Make a Uni-Value Grid 2034. Stock Price Fluctuation 2035. Partition Array Into Two Arrays to Minimize Sum Difference 2036. Maximum Alternating Subarray Sum 2037. Minimum Number of Moves to Seat Everyone 2038. Remove Colored Pieces if Both Neighbors are the Same Color 2039. The Time When the Network Becomes Idle 2040. Kth Smallest Product of Two Sorted Arrays 2041. Accepted Candidates From the Interviews 2042. Check if Numbers Are Ascending in a Sentence 2043. Simple Bank System 2044. Count Number of Maximum Bitwise-OR Subsets 2045. Second Minimum Time to Reach Destination 2046. Sort Linked List Already Sorted Using Absolute Values 2047. Number of Valid Words in a Sentence 2048. Next Greater Numerically Balanced Number 2049. Count Nodes With the Highest Score 2050. Parallel Courses III 2051. The Category of Each Member in the Store 2052. Minimum Cost to Separate Sentence Into Rows 2053. Kth Distinct String in an Array 2054. Two Best Non-Overlapping Events 2055. Plates Between Candles 2056. Number of Valid Move Combinations On Chessboard 2057. Smallest Index With Equal Value 2058. Find the Minimum and Maximum Number of Nodes Between Critical Points 2059. Minimum Operations to Convert Number 2060. Check if an Original String Exists Given Two Encoded Strings 2061. Number of Spaces Cleaning Robot Cleaned 2062. Count Vowel Substrings of a String 2063. Vowels of All Substrings 2064. Minimized Maximum of Products Distributed to Any Store 2065. Maximum Path Quality of a Graph 2066. Account Balance 2067. Number of Equal Count Substrings 2068. Check Whether Two Strings are Almost Equivalent 2069. Walking Robot Simulation II 2070. Most Beautiful Item for Each Query 2071. Maximum Number of Tasks You Can Assign 2072. The Winner University 2073. Time Needed to Buy Tickets 2074. Reverse Nodes in Even Length Groups 2075. Decode the Slanted Ciphertext 2076. Process Restricted Friend Requests 2077. Paths in Maze That Lead to Same Room 2078. Two Furthest Houses With Different Colors 2079. Watering Plants 2080. Range Frequency Queries 2081. Sum of k-Mirror Numbers 2082. The Number of Rich Customers 2083. Substrings That Begin and End With the Same Letter 2084. Drop Type 1 Orders for Customers With Type 0 Orders 2085. Count Common Words With One Occurrence 2086. Minimum Number of Buckets Required to Collect Rainwater from Houses 2087. Minimum Cost Homecoming of a Robot in a Grid 2088. Count Fertile Pyramids in a Land 2089. Find Target Indices After Sorting Array 2090. K Radius Subarray Averages 2091. Removing Minimum and Maximum From Array 2092. Find All People With Secret 2093. Minimum Cost to Reach City With Discounts 2094. Finding 3-Digit Even Numbers 2095. Delete the Middle Node of a Linked List 2096. Step-By-Step Directions From a Binary Tree Node to Another 2097. Valid Arrangement of Pairs 2098. Subsequence of Size K With the Largest Even Sum 2099. Find Subsequence of Length K With the Largest Sum 2100. Find Good Days to Rob the Bank 2101. Detonate the Maximum Bombs 2102. Sequentially Ordinal Rank Tracker 2103. Rings and Rods 2104. Sum of Subarray Ranges 2105. Watering Plants II 2106. Maximum Fruits Harvested After at Most K Steps 2107. Number of Unique Flavors After Sharing K Candies 2108. Find First Palindromic String in the Array 2109. Adding Spaces to a String 2110. Number of Smooth Descent Periods of a Stock 2111. Minimum Operations to Make the Array K-Increasing 2112. The Airport With the Most Traffic 2113. Elements in Array After Removing and Replacing Elements 2114. Maximum Number of Words Found in Sentences 2115. Find All Possible Recipes from Given Supplies 2116. Check if a Parentheses String Can Be Valid 2117. Abbreviating the Product of a Range 2118. Build the Equation 2119. A Number After a Double Reversal 2120. Execution of All Suffix Instructions Staying in a Grid 2121. Intervals Between Identical Elements 2122. Recover the Original Array 2123. Minimum Operations to Remove Adjacent Ones in Matrix 2124. Check if All A's Appears Before All B's 2125. Number of Laser Beams in a Bank 2126. Destroying Asteroids 2127. Maximum Employees to Be Invited to a Meeting 2128. Remove All Ones With Row and Column Flips 2129. Capitalize the Title 2130. Maximum Twin Sum of a Linked List 2131. Longest Palindrome by Concatenating Two Letter Words 2132. Stamping the Grid 2133. Check if Every Row and Column Contains All Numbers 2134. Minimum Swaps to Group All 1's Together II 2135. Count Words Obtained After Adding a Letter 2136. Earliest Possible Day of Full Bloom 2137. Pour Water Between Buckets to Make Water Levels Equal 2138. Divide a String Into Groups of Size k 2139. Minimum Moves to Reach Target Score 2140. Solving Questions With Brainpower 2141. Maximum Running Time of N Computers 2142. The Number of Passengers in Each Bus I 2143. Choose Numbers From Two Arrays in Range 2144. Minimum Cost of Buying Candies With Discount 2145. Count the Hidden Sequences 2146. K Highest Ranked Items Within a Price Range 2147. Number of Ways to Divide a Long Corridor 2148. Count Elements With Strictly Smaller and Greater Elements 2149. Rearrange Array Elements by Sign 2150. Find All Lonely Numbers in the Array 2151. Maximum Good People Based on Statements 2152. Minimum Number of Lines to Cover Points 2153. The Number of Passengers in Each Bus II 2154. Keep Multiplying Found Values by Two 2155. All Divisions With the Highest Score of a Binary Array 2156. Find Substring With Given Hash Value 2157. Groups of Strings 2158. Amount of New Area Painted Each Day 2159. Order Two Columns Independently 2160. Minimum Sum of Four Digit Number After Splitting Digits 2161. Partition Array According to Given Pivot 2162. Minimum Cost to Set Cooking Time 2163. Minimum Difference in Sums After Removal of Elements 2164. Sort Even and Odd Indices Independently 2165. Smallest Value of the Rearranged Number 2166. Design Bitset 2167. Minimum Time to Remove All Cars Containing Illegal Goods 2168. Unique Substrings With Equal Digit Frequency 2169. Count Operations to Obtain Zero 2170. Minimum Operations to Make the Array Alternating 2171. Removing Minimum Number of Magic Beans 2172. Maximum AND Sum of Array 2173. Longest Winning Streak 2174. Remove All Ones With Row and Column Flips II 2175. The Change in Global Rankings 2176. Count Equal and Divisible Pairs in an Array 2177. Find Three Consecutive Integers That Sum to a Given Number 2178. Maximum Split of Positive Even Integers 2179. Count Good Triplets in an Array 2180. Count Integers With Even Digit Sum 2181. Merge Nodes in Between Zeros 2182. Construct String With Repeat Limit 2183. Count Array Pairs Divisible by K 2184. Number of Ways to Build Sturdy Brick Wall 2185. Counting Words With a Given Prefix 2186. Minimum Number of Steps to Make Two Strings Anagram II 2187. Minimum Time to Complete Trips 2188. Minimum Time to Finish the Race 2189. Number of Ways to Build House of Cards 2190. Most Frequent Number Following Key In an Array 2191. Sort the Jumbled Numbers 2192. All Ancestors of a Node in a Directed Acyclic Graph 2193. Minimum Number of Moves to Make Palindrome 2194. Cells in a Range on an Excel Sheet 2195. Append K Integers With Minimal Sum 2196. Create Binary Tree From Descriptions 2197. Replace Non-Coprime Numbers in Array 2198. Number of Single Divisor Triplets 2199. Finding the Topic of Each Post 2200. Find All K-Distant Indices in an Array 2201. Count Artifacts That Can Be Extracted 2202. Maximize the Topmost Element After K Moves 2203. Minimum Weighted Subgraph With the Required Paths 2204. Distance to a Cycle in Undirected Graph 2205. The Number of Users That Are Eligible for Discount 2206. Divide Array Into Equal Pairs 2207. Maximize Number of Subsequences in a String 2208. Minimum Operations to Halve Array Sum 2209. Minimum White Tiles After Covering With Carpets 2210. Count Hills and Valleys in an Array 2211. Count Collisions on a Road 2212. Maximum Points in an Archery Competition 2213. Longest Substring of One Repeating Character 2214. Minimum Health to Beat Game 2215. Find the Difference of Two Arrays 2216. Minimum Deletions to Make Array Beautiful 2217. Find Palindrome With Fixed Length 2218. Maximum Value of K Coins From Piles 2219. Maximum Sum Score of Array 2220. Minimum Bit Flips to Convert Number 2221. Find Triangular Sum of an Array 2222. Number of Ways to Select Buildings 2223. Sum of Scores of Built Strings 2224. Minimum Number of Operations to Convert Time 2225. Find Players With Zero or One Losses 2226. Maximum Candies Allocated to K Children 2227. Encrypt and Decrypt Strings 2228. Users With Two Purchases Within Seven Days 2229. Check if an Array Is Consecutive 2230. The Users That Are Eligible for Discount 2231. Largest Number After Digit Swaps by Parity 2232. Minimize Result by Adding Parentheses to Expression 2233. Maximum Product After K Increments 2234. Maximum Total Beauty of the Gardens 2235. Add Two Integers 2236. Root Equals Sum of Children 2237. Count Positions on Street With Required Brightness 2238. Number of Times a Driver Was a Passenger 2239. Find Closest Number to Zero 2240. Number of Ways to Buy Pens and Pencils 2241. Design an ATM Machine 2242. Maximum Score of a Node Sequence 2243. Calculate Digit Sum of a String 2244. Minimum Rounds to Complete All Tasks 2245. Maximum Trailing Zeros in a Cornered Path 2246. Longest Path With Different Adjacent Characters 2247. Maximum Cost of Trip With K Highways 2248. Intersection of Multiple Arrays 2249. Count Lattice Points Inside a Circle 2250. Count Number of Rectangles Containing Each Point 2251. Number of Flowers in Full Bloom 2252. Dynamic Pivoting of a Table 2253. Dynamic Unpivoting of a Table 2254. Design Video Sharing Platform 2255. Count Prefixes of a Given String 2256. Minimum Average Difference 2257. Count Unguarded Cells in the Grid 2258. Escape the Spreading Fire 2259. Remove Digit From Number to Maximize Result 2260. Minimum Consecutive Cards to Pick Up 2261. K Divisible Elements Subarrays 2262. Total Appeal of A String 2263. Make Array Non-decreasing or Non-increasing 2264. Largest 3-Same-Digit Number in String 2265. Count Nodes Equal to Average of Subtree 2266. Count Number of Texts 2267. Check if There Is a Valid Parentheses String Path 2268. Minimum Number of Keypresses 2269. Find the K-Beauty of a Number 2270. Number of Ways to Split Array 2271. Maximum White Tiles Covered by a Carpet 2272. Substring With Largest Variance 2273. Find Resultant Array After Removing Anagrams 2274. Maximum Consecutive Floors Without Special Floors 2275. Largest Combination With Bitwise AND Greater Than Zero 2276. Count Integers in Intervals 2277. Closest Node to Path in Tree 2278. Percentage of Letter in String 2279. Maximum Bags With Full Capacity of Rocks 2280. Minimum Lines to Represent a Line Chart 2281. Sum of Total Strength of Wizards 2282. Number of People That Can Be Seen in a Grid 2283. Check if Number Has Equal Digit Count and Digit Value 2284. Sender With Largest Word Count 2285. Maximum Total Importance of Roads 2286. Booking Concert Tickets in Groups 2287. Rearrange Characters to Make Target String 2288. Apply Discount to Prices 2289. Steps to Make Array Non-decreasing 2290. Minimum Obstacle Removal to Reach Corner 2291. Maximum Profit From Trading Stocks 2292. Products With Three or More Orders in Two Consecutive Years 2293. Min Max Game 2294. Partition Array Such That Maximum Difference Is K 2295. Replace Elements in an Array 2296. Design a Text Editor 2297. Jump Game VIII 2298. Tasks Count in the Weekend 2299. Strong Password Checker II 2300. Successful Pairs of Spells and Potions 2301. Match Substring After Replacement 2302. Count Subarrays With Score Less Than K 2303. Calculate Amount Paid in Taxes 2304. Minimum Path Cost in a Grid 2305. Fair Distribution of Cookies 2306. Naming a Company 2307. Check for Contradictions in Equations 2308. Arrange Table by Gender 2309. Greatest English Letter in Upper and Lower Case 2310. Sum of Numbers With Units Digit K 2311. Longest Binary Subsequence Less Than or Equal to K 2312. Selling Pieces of Wood 2313. Minimum Flips in Binary Tree to Get Result 2314. The First Day of the Maximum Recorded Degree in Each City 2315. Count Asterisks 2316. Count Unreachable Pairs of Nodes in an Undirected Graph 2317. Maximum XOR After Operations 2318. Number of Distinct Roll Sequences 2319. Check if Matrix Is X-Matrix 2320. Count Number of Ways to Place Houses 2321. Maximum Score Of Spliced Array 2322. Minimum Score After Removals on a Tree 2323. Find Minimum Time to Finish All Jobs II 2324. Product Sales Analysis IV 2325. Decode the Message 2326. Spiral Matrix IV 2327. Number of People Aware of a Secret 2328. Number of Increasing Paths in a Grid 2329. Product Sales Analysis V 2330. Valid Palindrome IV 2331. Evaluate Boolean Binary Tree 2332. The Latest Time to Catch a Bus 2333. Minimum Sum of Squared Difference 2334. Subarray With Elements Greater Than Varying Threshold 2335. Minimum Amount of Time to Fill Cups 2336. Smallest Number in Infinite Set 2337. Move Pieces to Obtain a String 2338. Count the Number of Ideal Arrays 2339. All the Matches of the League 2340. Minimum Adjacent Swaps to Make a Valid Array 2341. Maximum Number of Pairs in Array 2342. Max Sum of a Pair With Equal Sum of Digits 2343. Query Kth Smallest Trimmed Number 2344. Minimum Deletions to Make Array Divisible 2345. Finding the Number of Visible Mountains 2346. Compute the Rank as a Percentage 2347. Best Poker Hand 2348. Number of Zero-Filled Subarrays 2349. Design a Number Container System 2350. Shortest Impossible Sequence of Rolls 2351. First Letter to Appear Twice 2352. Equal Row and Column Pairs 2353. Design a Food Rating System 2354. Number of Excellent Pairs 2355. Maximum Number of Books You Can Take 2356. Number of Unique Subjects Taught by Each Teacher 2357. Make Array Zero by Subtracting Equal Amounts 2358. Maximum Number of Groups Entering a Competition 2359. Find Closest Node to Given Two Nodes 2360. Longest Cycle in a Graph 2361. Minimum Costs Using the Train Line 2362. Generate the Invoice 2363. Merge Similar Items 2364. Count Number of Bad Pairs 2365. Task Scheduler II 2366. Minimum Replacements to Sort the Array 2367. Number of Arithmetic Triplets 2368. Reachable Nodes With Restrictions 2369. Check if There is a Valid Partition For The Array 2370. Longest Ideal Subsequence 2371. Minimize Maximum Value in a Grid 2372. Calculate the Influence of Each Salesperson 2373. Largest Local Values in a Matrix 2374. Node With Highest Edge Score 2375. Construct Smallest Number From DI String 2376. Count Special Integers 2377. Sort the Olympic Table 2378. Choose Edges to Maximize Score in a Tree 2379. Minimum Recolors to Get K Consecutive Black Blocks 2380. Time Needed to Rearrange a Binary String 2381. Shifting Letters II 2382. Maximum Segment Sum After Removals 2383. Minimum Hours of Training to Win a Competition 2384. Largest Palindromic Number 2385. Amount of Time for Binary Tree to Be Infected 2386. Find the K-Sum of an Array 2387. Median of a Row Wise Sorted Matrix 2388. Change Null Values in a Table to the Previous Value 2389. Longest Subsequence With Limited Sum 2390. Removing Stars From a String 2391. Minimum Amount of Time to Collect Garbage 2392. Build a Matrix With Conditions 2393. Count Strictly Increasing Subarrays 2394. Employees With Deductions 2395. Find Subarrays With Equal Sum 2396. Strictly Palindromic Number 2397. Maximum Rows Covered by Columns 2398. Maximum Number of Robots Within Budget 2399. Check Distances Between Same Letters 2400. Number of Ways to Reach a Position After Exactly k Steps 2401. Longest Nice Subarray 2402. Meeting Rooms III 2403. Minimum Time to Kill All Monsters 2404. Most Frequent Even Element 2405. Optimal Partition of String 2406. Divide Intervals Into Minimum Number of Groups 2407. Longest Increasing Subsequence II 2408. Design SQL 2409. Count Days Spent Together 2410. Maximum Matching of Players With Trainers 2411. Smallest Subarrays With Maximum Bitwise OR 2412. Minimum Money Required Before Transactions 2413. Smallest Even Multiple 2414. Length of the Longest Alphabetical Continuous Substring 2415. Reverse Odd Levels of Binary Tree 2416. Sum of Prefix Scores of Strings 2417. Closest Fair Integer 2418. Sort the People 2419. Longest Subarray With Maximum Bitwise AND 2420. Find All Good Indices 2421. Number of Good Paths 2422. Merge Operations to Turn Array Into a Palindrome 2423. Remove Letter To Equalize Frequency 2424. Longest Uploaded Prefix 2425. Bitwise XOR of All Pairings 2426. Number of Pairs Satisfying Inequality 2427. Number of Common Factors 2428. Maximum Sum of an Hourglass 2429. Minimize XOR 2430. Maximum Deletions on a String 2431. Maximize Total Tastiness of Purchased Fruits 2432. The Employee That Worked on the Longest Task 2433. Find The Original Array of Prefix Xor 2434. Using a Robot to Print the Lexicographically Smallest String 2435. Paths in Matrix Whose Sum Is Divisible by K 2436. Minimum Split Into Subarrays With GCD Greater Than One 2437. Number of Valid Clock Times 2438. Range Product Queries of Powers 2439. Minimize Maximum of Array 2440. Create Components With Same Value 2441. Largest Positive Integer That Exists With Its Negative 2442. Count Number of Distinct Integers After Reverse Operations 2443. Sum of Number and Its Reverse 2444. Count Subarrays With Fixed Bounds 2445. Number of Nodes With Value One 2446. Determine if Two Events Have Conflict 2447. Number of Subarrays With GCD Equal to K 2448. Minimum Cost to Make Array Equal 2449. Minimum Number of Operations to Make Arrays Similar 2450. Number of Distinct Binary Strings After Applying Operations 2451. Leetcode Problem 2452. Leetcode Problem 2453. Leetcode Problem 2454. Leetcode Problem 2455. Leetcode Problem 2456. Leetcode Problem 2457. Leetcode Problem 2458. Leetcode Problem 2459. Leetcode Problem 2460. Leetcode Problem 2461. Leetcode Problem 2462. Leetcode Problem 2463. Leetcode Problem 2464. Leetcode Problem 2465. Leetcode Problem 2466. Leetcode Problem 2467. Leetcode Problem 2468. Leetcode Problem 2469. Leetcode Problem 2470. Leetcode Problem 2471. Leetcode Problem 2472. Leetcode Problem 2473. Leetcode Problem 2474. Leetcode Problem 2475. Leetcode Problem 2476. Leetcode Problem 2477. Leetcode Problem 2478. Leetcode Problem 2479. Leetcode Problem 2480. Leetcode Problem 2481. Leetcode Problem 2482. Leetcode Problem 2483. Leetcode Problem 2484. Leetcode Problem 2485. Leetcode Problem 2486. Leetcode Problem 2487. Leetcode Problem 2488. Leetcode Problem 2489. Leetcode Problem 2490. Leetcode Problem 2491. Leetcode Problem 2492. Leetcode Problem 2493. Leetcode Problem 2494. Leetcode Problem 2495. Leetcode Problem 2496. Leetcode Problem 2497. Leetcode Problem 2498. Leetcode Problem 2499. Leetcode Problem 2500. Leetcode Problem 2501. Leetcode Problem 2502. Leetcode Problem 2503. Leetcode Problem 2504. Leetcode Problem 2505. Leetcode Problem 2506. Leetcode Problem 2507. Leetcode Problem 2508. Leetcode Problem 2509. Leetcode Problem 2510. Leetcode Problem 2511. Leetcode Problem 2512. Leetcode Problem 2513. Leetcode Problem 2514. Leetcode Problem 2515. Leetcode Problem 2516. Leetcode Problem 2517. Leetcode Problem 2518. Leetcode Problem 2519. Leetcode Problem 2520. Leetcode Problem

			

class Solution {
 public:
  int countNodes(TreeNode* root) {
    if (root == nullptr)
      return 0;
    return 1 + countNodes(root->left) + countNodes(root->right);
  }
};

			

class Solution {
  public int countNodes(TreeNode root) {
    if (root == null)
      return 0;
    return 1 + countNodes(root.left) + countNodes(root.right);
  }
}

			

class Solution:
  def countNodes(self, root: Optional[TreeNode]) -> int:
    if not root:
      return 0
    return 1 + self.countNodes(root.left) + self.countNodes(root.right)