| 1 | Two Sum | Easy |
| 2 | Add Two Numbers | Medium |
| 3 | Longest Substring Without Repeating Characters | Medium |
| 4 | Median of Two Sorted Arrays | Hard |
| 5 | Longest Palindromic Substring | Medium |
| 6 | ZigZag Conversion | Medium |
| 7 | Reverse Integer | Easy |
| 8 | String to Integer (atoi) | Medium |
| 9 | Palindrome Number | Easy |
| 10 | Regular Expression Matching | Hard |
| 11 | Container With Most Water | Medium |
| 12 | Integer to Roman | Medium |
| 13 | Roman to Integer | Easy |
| 14 | Longest Common Prefix | Easy |
| 15 | 3Sum | Medium |
| 16 | 3Sum Closest | Medium |
| 17 | Letter Combinations of a Phone Number | Medium |
| 18 | 4Sum | Medium |
| 19 | Remove Nth Node From End of List | Medium |
| 20 | Valid Parentheses | Easy |
| 21 | Merge Two Sorted Lists | Easy |
| 22 | Generate Parentheses | Medium |
| 23 | Merge k Sorted Lists | Hard |
| 24 | Swap Nodes in Pairs | Medium |
| 25 | Reverse Nodes in k-Group | Hard |
| 26 | Remove Duplicates from Sorted Array | Easy |
| 27 | Remove Element | Easy |
| 28 | Implement strStr() | Easy |
| 29 | Divide Two Integers | Medium |
| 30 | Substring with Concatenation of All Words | Hard |
| 31 | Next Permutation | Medium |
| 32 | Longest Valid Parentheses | Hard |
| 33 | Search in Rotated Sorted Array | Medium |
| 34 | Find First and Last Position of Element in Sorted Array | Medium |
| 35 | Search Insert Position | Easy |
| 36 | Valid Sudoku | Medium |
| 37 | Sudoku Solver | Hard |
| 38 | Count and Say | Medium |
| 39 | Combination Sum | Medium |
| 40 | Combination Sum II | Medium |
| 41 | First Missing Positive | Hard |
| 42 | Trapping Rain Water | Hard |
| 43 | Multiply Strings | Medium |
| 44 | Wildcard Matching | Hard |
| 45 | Jump Game II | Medium |
| 46 | Permutations | Medium |
| 47 | Permutations II | Medium |
| 48 | Rotate Image | Medium |
| 49 | Group Anagrams | Medium |
| 50 | Pow(x, n) | Medium |
| 51 | N-Queens | Hard |
| 52 | N-Queens II | Hard |
| 53 | Maximum Subarray | Easy |
| 54 | Spiral Matrix | Medium |
| 55 | Jump Game | Medium |
| 56 | Merge Intervals | Medium |
| 57 | Insert Interval | Medium |
| 58 | Length of Last Word | Easy |
| 59 | Spiral Matrix II | Medium |
| 60 | Permutation Sequence | Hard |
| 61 | Rotate List | Medium |
| 62 | Unique Paths | Medium |
| 63 | Unique Paths II | Medium |
| 64 | Minimum Path Sum | Medium |
| 65 | Valid Number | Hard |
| 66 | Plus One | Easy |
| 67 | Add Binary | Easy |
| 68 | Text Justification | Hard |
| 69 | Sqrt(x) | Medium |
| 70 | Climbing Stairs | Easy |
| 71 | Simplify Path | Medium |
| 72 | Edit Distance | Medium |
| 73 | Set Matrix Zeroes | Medium |
| 74 | Search a 2D Matrix | Medium |
| 75 | Sort Colors | Medium |
| 76 | Minimum Window Substring | Hard |
| 77 | Combinations | Medium |
| 78 | Subsets | Medium |
| 79 | Word Search | Medium |
| 80 | Remove Duplicates from Sorted Array II | Medium |
| 81 | Search in Rotated Sorted Array II | Medium |
| 82 | Remove Duplicates from Sorted List II | Medium |
| 83 | Remove Duplicates from Sorted List | Easy |
| 84 | Largest Rectangle in Histogram | Hard |
| 85 | Maximal Rectangle | Hard |
| 86 | Partition List | Medium |
| 87 | Scramble String | Hard |
| 88 | Merge Sorted Array | Easy |
| 89 | Gray Code | Medium |
| 90 | Subsets II | Medium |
| 91 | Decode Ways | Medium |
| 92 | Reverse Linked List II | Medium |
| 93 | Restore IP Addresses | Medium |
| 94 | Binary Tree Inorder Traversal | Easy |
| 95 | Unique Binary Search Trees II | Medium |
| 96 | Unique Binary Search Trees | Medium |
| 97 | Interleaving String | Medium |
| 98 | Validate Binary Search Tree | Medium |
| 99 | Recover Binary Search Tree | Medium |
| 100 | Same Tree | Easy |
| 101 | Symmetric Tree | Easy |
| 102 | Binary Tree Level Order Traversal | Medium |
| 103 | Binary Tree Zigzag Level Order Traversal | Medium |
| 104 | Maximum Depth of Binary Tree | Easy |
| 105 | Construct Binary Tree from Preorder and Inorder Traversal | Medium |
| 106 | Construct Binary Tree from Inorder and Postorder Traversal | Medium |
| 107 | Binary Tree Level Order Traversal II | Medium |
| 108 | Convert Sorted Array to Binary Search Tree | Easy |
| 109 | Convert Sorted List to Binary Search Tree | Medium |
| 110 | Balanced Binary Tree | Easy |
| 111 | Minimum Depth of Binary Tree | Easy |
| 112 | Path Sum | Easy |
| 113 | Path Sum II | Medium |
| 114 | Flatten Binary Tree to Linked List | Medium |
| 115 | Distinct Subsequences | Hard |
| 116 | Populating Next Right Pointers in Each Node | Medium |
| 117 | Populating Next Right Pointers in Each Node II | Medium |
| 118 | Pascal's Triangle | Easy |
| 119 | Pascal's Triangle II | Easy |
| 120 | Triangle | Medium |
| 121 | Best Time to Buy and Sell Stock | Easy |
| 122 | Best Time to Buy and Sell Stock II | Medium |
| 123 | Best Time to Buy and Sell Stock III | Hard |
| 124 | Binary Tree Maximum Path Sum | Hard |
| 125 | Valid Palindrome | Easy |
| 126 | Word Ladder II | Hard |
| 127 | Word Ladder | Hard |
| 128 | Longest Consecutive Sequence | Medium |
| 129 | Sum Root to Leaf Numbers | Medium |
| 130 | Surrounded Regions | Medium |
| 131 | Palindrome Partitioning | Medium |
| 132 | Palindrome Partitioning II | Hard |
| 133 | Clone Graph | Medium |
| 134 | Gas Station | Medium |
| 135 | Candy | Hard |
| 136 | Single Number | Easy |
| 137 | Single Number II | Medium |
| 138 | Copy List with Random Pointer | Medium |
| 139 | Word Break | Medium |
| 140 | Word Break II | Hard |
| 141 | Linked List Cycle | Easy |
| 142 | Linked List Cycle II | Medium |
| 143 | Reorder List | Medium |
| 144 | Binary Tree Preorder Traversal | Easy |
| 145 | Binary Tree Postorder Traversal | Easy |
| 146 | LRU Cache | Medium |
| 147 | Insertion Sort List | Medium |
| 148 | Sort List | Medium |
| 149 | Max Points on a Line | Hard |
| 150 | Evaluate Reverse Polish Notation | Medium |
| 151 | Reverse Words in a String | Medium |
| 152 | Maximum Product Subarray | Medium |
| 153 | Find Minimum in Rotated Sorted Array | Medium |
| 154 | Find Minimum in Rotated Sorted Array II | Hard |
| 155 | Min Stack | Medium |
| 160 | Intersection of Two Linked Lists | Medium |
| 162 | Find Peak Element | Medium |
| 164 | Maximum Gap | Medium |
| 165 | Compare Version Numbers | Medium |
| 166 | Fraction to Recurring Decimal | Medium |
| 167 | Two Sum II - Input Array Is Sorted | Easy |
| 168 | Excel Sheet Column Title | Easy |
| 169 | Majority Element | Easy |
| 171 | Excel Sheet Column Number | Easy |
| 172 | Factorial Trailing Zeroes | Medium |
| 173 | Binary Search Tree Iterator | Medium |
| 174 | Dungeon Game | Hard |
| 179 | Largest Number | Medium |
| 187 | Repeated DNA Sequences | Medium |
| 188 | Best Time to Buy and Sell Stock IV | Hard |
| 189 | Rotate Array | Medium |
| 190 | Reverse Bits | Easy |
| 191 | Number of 1 Bits | Easy |
| 198 | House Robber | Medium |
| 199 | Binary Tree Right Side View | Medium |
| 200 | Number of Islands | Medium |
| 201 | Bitwise AND of Numbers Range | Medium |
| 202 | Happy Number | Easy |
| 203 | Remove Linked List Elements | Easy |
| 204 | Count Primes | Medium |
| 205 | Isomorphic Strings | Easy |
| 206 | Reverse Linked List | Easy |
| 207 | Course Schedule | Medium |
| 208 | Implement Trie (Prefix Tree) | Medium |
| 209 | Minimum Size Subarray Sum | Medium |
| 210 | Course Schedule II | Medium |
| 211 | Design Add and Search Words Data Structure | Medium |
| 212 | Word Search II | Hard |
| 213 | House Robber II | Medium |
| 214 | Shortest Palindrome | Hard |
| 215 | Kth Largest Element in an Array | Medium |
| 216 | Combination Sum III | Medium |
| 217 | Contains Duplicate | Easy |
| 218 | The Skyline Problem | Hard |
| 219 | Contains Duplicate II | Easy |
| 220 | Contains Duplicate III | Hard |
| 221 | Maximal Square | Medium |
| 222 | Count Complete Tree Nodes | Easy |
| 223 | Rectangle Area | Medium |
| 224 | Basic Calculator | Hard |
| 225 | Implement Stack using Queues | Easy |
| 226 | Invert Binary Tree | Easy |
| 227 | Basic Calculator II | Medium |
| 228 | Summary Ranges | Easy |
| 229 | Majority Element II | Medium |
| 230 | Kth Smallest Element in a BST | Medium |
| 231 | Power of Two | Easy |
| 232 | Implement Queue using Stacks | Easy |
| 233 | Number of Digit One | Hard |
| 234 | Palindrome Linked List | Easy |
| 235 | Lowest Common Ancestor of a Binary Search Tree | Easy |
| 236 | Lowest Common Ancestor of a Binary Tree | Medium |
| 237 | Delete Node in a Linked List | Easy |
| 238 | Product of Array Except Self | Medium |
| 239 | Sliding Window Maximum | Hard |
| 240 | Search a 2D Matrix II | Medium |
| 241 | Different Ways to Add Parentheses | Medium |
| 242 | Valid Anagram | Easy |
| 257 | Binary Tree Paths | Easy |
| 258 | Add Digits | Easy |
| 260 | Single Number III | Medium |
| 263 | Ugly Number | Easy |
| 264 | Ugly Number II | Medium |
| 268 | Missing Number | Easy |
| 273 | Integer to English Words | Hard |
| 274 | H-Index | Medium |
| 275 | H-Index II | Medium |
| 278 | First Bad Version | Medium |
| 279 | Perfect Squares | Medium |
| 282 | Expression Add Operators | Hard |
| 283 | Move Zeroes | Easy |
| 284 | Peeking Iterator | Medium |
| 287 | Find the Duplicate Number | Medium |
| 289 | Game of Life | Medium |
| 290 | Word Pattern | Easy |
| 292 | Nim Game | Easy |
| 295 | Find Median from Data Stream | Hard |
| 297 | Serialize and Deserialize Binary Tree | Hard |
| 299 | Bulls and Cows | Medium |
| 300 | Longest Increasing Subsequence | Medium |
| 301 | Remove Invalid Parentheses | Hard |
| 303 | Range Sum Query - Immutable | Easy |
| 304 | Range Sum Query 2D - Immutable | Medium |
| 306 | Additive Number | Medium |
| 307 | Range Sum Query - Mutable | Medium |
| 309 | Best Time to Buy and Sell Stock with Cooldown | Medium |
| 310 | Minimum Height Trees | Medium |
| 312 | Burst Balloons | Hard |
| 313 | Super Ugly Number | Medium |
| 315 | Count of Smaller Numbers After Self | Hard |
| 316 | Remove Duplicate Letters | Medium |
| 318 | Maximum Product of Word Lengths | Medium |
| 319 | Bulb Switcher | Medium |
| 321 | Create Maximum Number | Hard |
| 322 | Coin Change | Medium |
| 324 | Wiggle Sort II | Medium |
| 326 | Power of Three | Easy |
| 327 | Count of Range Sum | Hard |
| 328 | Odd Even Linked List | Medium |
| 329 | Longest Increasing Path in a Matrix | Hard |
| 330 | Patching Array | Hard |
| 331 | Verify Preorder Serialization of a Binary Tree | Medium |
| 332 | Reconstruct Itinerary | Hard |
| 334 | Increasing Triplet Subsequence | Medium |
| 335 | Self Crossing | Hard |
| 336 | Palindrome Pairs | Hard |
| 337 | House Robber III | Medium |
| 338 | Counting Bits | Easy |
| 341 | Flatten Nested List Iterator | Medium |
| 342 | Power of Four | Easy |
| 343 | Integer Break | Medium |
| 344 | Reverse String | Easy |
| 345 | Reverse Vowels of a String | Easy |
| 347 | Top K Frequent Elements | Medium |
| 349 | Intersection of Two Arrays | Easy |
| 350 | Intersection of Two Arrays II | Easy |
| 352 | Data Stream as Disjoint Intervals | Hard |
| 354 | Russian Doll Envelopes | Hard |
| 355 | Design Twitter | Medium |
| 357 | Count Numbers with Unique Digits | Medium |
| 363 | Max Sum of Rectangle No Larger Than K | Hard |
| 365 | Water and Jug Problem | Medium |
| 367 | Valid Perfect Square | Easy |
| 368 | Largest Divisible Subset | Medium |
| 371 | Sum of Two Integers | Medium |
| 372 | Super Pow | Medium |
| 373 | Find K Pairs with Smallest Sums | Medium |
| 374 | Guess Number Higher or Lower | Medium |
| 375 | Guess Number Higher or Lower II | Medium |
| 376 | Wiggle Subsequence | Medium |
| 377 | Combination Sum IV | Medium |
| 378 | Kth Smallest Element in a Sorted Matrix | Medium |
| 380 | Insert Delete GetRandom O(1) | Medium |
| 381 | Insert Delete GetRandom O(1) - Duplicates allowed | Hard |
| 382 | Linked List Random Node | Medium |
| 383 | Ransom Note | Easy |
| 384 | Shuffle an Array | Medium |
| 385 | Mini Parser | Medium |
| 386 | Lexicographical Numbers | Medium |
| 387 | First Unique Character in a String | Easy |
| 388 | Longest Absolute File Path | Medium |
| 389 | Find the Difference | Easy |
| 390 | Elimination Game | Medium |
| 391 | Perfect Rectangle | Hard |
| 392 | Is Subsequence | Easy |
| 393 | UTF-8 Validation | Medium |
| 394 | Decode String | Medium |
| 395 | Longest Substring with At Least K Repeating Characters | Medium |
| 396 | Rotate Function | Medium |
| 397 | Integer Replacement | Medium |
| 398 | Random Pick Index | Medium |
| 399 | Evaluate Division | Medium |
| 400 | Nth Digit | Medium |
| 401 | Binary Watch | Easy |
| 402 | Remove K Digits | Medium |
| 403 | Frog Jump | Hard |
| 404 | Sum of Left Leaves | Easy |
| 405 | Convert a Number to Hexadecimal | Easy |
| 406 | Queue Reconstruction by Height | Medium |
| 407 | Trapping Rain Water II | Hard |
| 409 | Longest Palindrome | Easy |
| 410 | Split Array Largest Sum | Hard |
| 412 | Fizz Buzz | Easy |
| 413 | Arithmetic Slices | Medium |
| 414 | Third Maximum Number | Easy |
| 415 | Add Strings | Easy |
| 416 | Partition Equal Subset Sum | Medium |
| 417 | Pacific Atlantic Water Flow | Medium |
| 419 | Battleships in a Board | Medium |
| 420 | Strong Password Checker | Hard |
| 421 | Maximum XOR of Two Numbers in an Array | Medium |
| 423 | Reconstruct Original Digits from English | Medium |
| 424 | Longest Repeating Character Replacement | Medium |
| 427 | Construct Quad Tree | Medium |
| 429 | N-ary Tree Level Order Traversal | Medium |
| 430 | Flatten a Multilevel Doubly Linked List | Medium |
| 432 | All O`one Data Structure | Hard |
| 433 | Minimum Genetic Mutation | Medium |
| 434 | Number of Segments in a String | Easy |
| 435 | Non-overlapping Intervals | Medium |
| 436 | Find Right Interval | Medium |
| 437 | Path Sum III | Medium |
| 438 | Find All Anagrams in a String | Medium |
| 440 | K-th Smallest in Lexicographical Order | Hard |
| 441 | Arranging Coins | Easy |
| 442 | Find All Duplicates in an Array | Medium |
| 443 | String Compression | Medium |
| 445 | Add Two Numbers II | Medium |
| 446 | Arithmetic Slices II - Subsequence | Hard |
| 447 | Number of Boomerangs | Medium |
| 448 | Find All Numbers Disappeared in an Array | Easy |
| 449 | Serialize and Deserialize BST | Medium |
| 450 | Delete Node in a BST | Medium |
| 451 | Sort Characters By Frequency | Medium |
| 452 | Minimum Number of Arrows to Burst Balloons | Medium |
| 453 | Minimum Moves to Equal Array Elements | Medium |
| 454 | 4Sum II | Medium |
| 455 | Assign Cookies | Easy |
| 456 | 132 Pattern | Medium |
| 457 | Circular Array Loop | Medium |
| 458 | Poor Pigs | Hard |
| 459 | Repeated Substring Pattern | Easy |
| 460 | LFU Cache | Hard |
| 461 | Hamming Distance | Easy |
| 462 | Minimum Moves to Equal Array Elements II | Medium |
| 463 | Island Perimeter | Medium |
| 464 | Can I Win | Medium |
| 466 | Count The Repetitions | Hard |
| 467 | Unique Substrings in Wraparound String | Medium |
| 468 | Validate IP Address | Medium |
| 470 | Implement Rand10() Using Rand7() | Medium |
| 472 | Concatenated Words | Hard |
| 473 | Matchsticks to Square | Medium |
| 474 | Ones and Zeroes | Medium |
| 475 | Heaters | Medium |
| 476 | Number Complement | Easy |
| 477 | Total Hamming Distance | Medium |
| 478 | Generate Random Point in a Circle | Medium |
| 479 | Largest Palindrome Product | Hard |
| 480 | Sliding Window Median | Hard |
| 481 | Magical String | Medium |
| 482 | License Key Formatting | Easy |
| 483 | Smallest Good Base | Hard |
| 485 | Max Consecutive Ones | Easy |
| 486 | Predict the Winner | Medium |
| 488 | Zuma Game | Hard |
| 491 | Non-decreasing Subsequences | Medium |
| 492 | Construct the Rectangle | Easy |
| 493 | Reverse Pairs | Hard |
| 494 | Target Sum | Medium |
| 495 | Teemo Attacking | Easy |
| 496 | Next Greater Element I | Easy |
| 497 | Random Point in Non-overlapping Rectangles | Medium |
| 498 | Diagonal Traverse | Medium |
| 500 | Keyboard Row | Easy |
| 501 | Find Mode in Binary Search Tree | Easy |
| 502 | IPO | Hard |
| 503 | Next Greater Element II | Medium |
| 504 | Base 7 | Easy |
| 506 | Relative Ranks | Easy |
| 507 | Perfect Number | Easy |
| 508 | Most Frequent Subtree Sum | Medium |
| 509 | Fibonacci Number | Easy |
| 513 | Find Bottom Left Tree Value | Medium |
| 514 | Freedom Trail | Hard |
| 515 | Find Largest Value in Each Tree Row | Medium |
| 516 | Longest Palindromic Subsequence | Medium |
| 517 | Super Washing Machines | Hard |
| 518 | Coin Change II | Medium |
| 519 | Random Flip Matrix | Medium |
| 520 | Detect Capital | Easy |
| 521 | Longest Uncommon Subsequence I | Easy |
| 522 | Longest Uncommon Subsequence II | Medium |
| 523 | Continuous Subarray Sum | Medium |
| 524 | Longest Word in Dictionary through Deleting | Medium |
| 525 | Contiguous Array | Medium |
| 526 | Beautiful Arrangement | Medium |
| 528 | Random Pick with Weight | Medium |
| 529 | Minesweeper | Medium |
| 530 | Minimum Absolute Difference in BST | Easy |
| 532 | K-diff Pairs in an Array | Medium |
| 537 | Complex Number Multiplication | Medium |
| 538 | Convert BST to Greater Tree | Medium |
| 539 | Minimum Time Difference | Medium |
| 540 | Single Element in a Sorted Array | Medium |
| 541 | Reverse String II | Easy |
| 542 | 01 Matrix | Medium |
| 543 | Diameter of Binary Tree | Easy |
| 546 | Remove Boxes | Hard |
| 547 | Number of Provinces | Medium |
| 551 | Student Attendance Record I | Easy |
| 552 | Student Attendance Record II | Hard |
| 553 | Optimal Division | Medium |
| 554 | Brick Wall | Medium |
| 556 | Next Greater Element III | Medium |
| 557 | Reverse Words in a String III | Easy |
| 558 | Logical OR of Two Binary Grids Represented as Quad-Trees | Medium |
| 559 | Maximum Depth of N-ary Tree | Easy |
| 560 | Subarray Sum Equals K | Medium |
| 563 | Binary Tree Tilt | Easy |
| 564 | Find the Closest Palindrome | Hard |
| 565 | Array Nesting | Medium |
| 566 | Reshape the Matrix | Easy |
| 567 | Permutation in String | Medium |
| 572 | Subtree of Another Tree | Easy |
| 575 | Distribute Candies | Easy |
| 576 | Out of Boundary Paths | Medium |
| 581 | Shortest Unsorted Continuous Subarray | Medium |
| 583 | Delete Operation for Two Strings | Medium |
| 587 | Erect the Fence | Hard |
| 589 | N-ary Tree Preorder Traversal | Easy |
| 590 | N-ary Tree Postorder Traversal | Easy |
| 591 | Tag Validator | Hard |
| 592 | Fraction Addition and Subtraction | Medium |
| 593 | Valid Square | Medium |
| 594 | Longest Harmonious Subsequence | Easy |
| 598 | Range Addition II | Easy |
| 599 | Minimum Index Sum of Two Lists | Easy |
| 600 | Non-negative Integers without Consecutive Ones | Hard |
| 605 | Can Place Flowers | Easy |
| 606 | Construct String from Binary Tree | Easy |
| 609 | Find Duplicate File in System | Medium |
| 611 | Valid Triangle Number | Medium |
| 617 | Merge Two Binary Trees | Easy |
| 621 | Task Scheduler | Medium |
| 622 | Design Circular Queue | Medium |
| 623 | Add One Row to Tree | Medium |
| 624 | Maximum Distance in Arrays | Medium |
| 628 | Maximum Product of Three Numbers | Easy |
| 629 | K Inverse Pairs Array | Hard |
| 630 | Course Schedule III | Hard |
| 632 | Smallest Range Covering Elements from K Lists | Hard |
| 633 | Sum of Square Numbers | Medium |
| 636 | Exclusive Time of Functions | Medium |
| 637 | Average of Levels in Binary Tree | Easy |
| 638 | Shopping Offers | Medium |
| 639 | Decode Ways II | Hard |
| 640 | Solve the Equation | Medium |
| 641 | Design Circular Deque | Medium |
| 643 | Maximum Average Subarray I | Easy |
| 645 | Set Mismatch | Medium |
| 646 | Maximum Length of Pair Chain | Medium |
| 647 | Palindromic Substrings | Medium |
| 648 | Replace Words | Medium |
| 649 | Dota2 Senate | Medium |
| 650 | 2 Keys Keyboard | Medium |
| 652 | Find Duplicate Subtrees | Medium |
| 653 | Two Sum IV - Input is a BST | Easy |
| 654 | Maximum Binary Tree | Medium |
| 655 | Print Binary Tree | Medium |
| 657 | Robot Return to Origin | Easy |
| 658 | Find K Closest Elements | Medium |
| 659 | Split Array into Consecutive Subsequences | Medium |
| 661 | Image Smoother | Easy |
| 662 | Maximum Width of Binary Tree | Medium |
| 664 | Strange Printer | Hard |
| 665 | Non-decreasing Array | Medium |
| 667 | Beautiful Arrangement II | Medium |
| 668 | Kth Smallest Number in Multiplication Table | Hard |
| 669 | Trim a Binary Search Tree | Medium |
| 670 | Maximum Swap | Medium |
| 671 | Second Minimum Node In a Binary Tree | Easy |
| 672 | Bulb Switcher II | Medium |
| 673 | Number of Longest Increasing Subsequence | Medium |
| 674 | Longest Continuous Increasing Subsequence | Easy |
| 675 | Cut Off Trees for Golf Event | Hard |
| 676 | Implement Magic Dictionary | Medium |
| 677 | Map Sum Pairs | Medium |
| 678 | Valid Parenthesis String | Medium |
| 679 | 24 Game | Hard |
| 680 | Valid Palindrome II | Easy |
| 682 | Baseball Game | Easy |
| 684 | Redundant Connection | Medium |
| 685 | Redundant Connection II | Hard |
| 686 | Repeated String Match | Easy |
| 687 | Longest Univalue Path | Medium |
| 688 | Knight Probability in Chessboard | Medium |
| 689 | Maximum Sum of 3 Non-Overlapping Subarrays | Hard |
| 690 | Employee Importance | Medium |
| 691 | Stickers to Spell Word | Hard |
| 692 | Top K Frequent Words | Medium |
| 693 | Binary Number with Alternating Bits | Easy |
| 695 | Max Area of Island | Medium |
| 696 | Count Binary Substrings | Easy |
| 697 | Degree of an Array | Easy |
| 698 | Partition to K Equal Sum Subsets | Medium |
| 699 | Falling Squares | Hard |
| 700 | Search in a Binary Search Tree | Easy |
| 701 | Insert into a Binary Search Tree | Medium |
| 703 | Kth Largest Element in a Stream | Easy |
| 704 | Binary Search | Easy |
| 705 | Design HashSet | Easy |
| 706 | Design HashMap | Easy |
| 707 | Design Linked List | Medium |
| 710 | Random Pick with Blacklist | Hard |
| 712 | Minimum ASCII Delete Sum for Two Strings | Medium |
| 713 | Subarray Product Less Than K | Medium |
| 714 | Best Time to Buy and Sell Stock with Transaction Fee | Medium |
| 715 | Range Module | Hard |
| 717 | 1-bit and 2-bit Characters | Easy |
| 718 | Maximum Length of Repeated Subarray | Medium |
| 719 | Find K-th Smallest Pair Distance | Hard |
| 720 | Longest Word in Dictionary | Medium |
| 721 | Accounts Merge | Medium |
| 722 | Remove Comments | Medium |
| 724 | Find Pivot Index | Easy |
| 725 | Split Linked List in Parts | Medium |
| 726 | Number of Atoms | Hard |
| 728 | Self Dividing Numbers | Easy |
| 729 | My Calendar I | Medium |
| 730 | Count Different Palindromic Subsequences | Hard |
| 731 | My Calendar II | Medium |
| 732 | My Calendar III | Hard |
| 733 | Flood Fill | Easy |
| 735 | Asteroid Collision | Medium |
| 736 | Parse Lisp Expression | Hard |
| 738 | Monotone Increasing Digits | Medium |
| 739 | Daily Temperatures | Medium |
| 740 | Delete and Earn | Medium |
| 741 | Cherry Pickup | Hard |
| 743 | Network Delay Time | Medium |
| 744 | Find Smallest Letter Greater Than Target | Easy |
| 745 | Prefix and Suffix Search | Hard |
| 746 | Min Cost Climbing Stairs | Easy |
| 747 | Largest Number At Least Twice of Others | Easy |
| 748 | Shortest Completing Word | Easy |
| 749 | Contain Virus | Hard |
| 752 | Open the Lock | Medium |
| 753 | Cracking the Safe | Hard |
| 754 | Reach a Number | Medium |
| 756 | Pyramid Transition Matrix | Medium |
| 757 | Set Intersection Size At Least Two | Hard |
| 761 | Special Binary String | Hard |
| 762 | Prime Number of Set Bits in Binary Representation | Easy |
| 763 | Partition Labels | Medium |
| 764 | Largest Plus Sign | Medium |
| 765 | Couples Holding Hands | Hard |
| 766 | Toeplitz Matrix | Easy |
| 767 | Reorganize String | Medium |
| 768 | Max Chunks To Make Sorted II | Hard |
| 769 | Max Chunks To Make Sorted | Medium |
| 770 | Basic Calculator IV | Hard |
| 773 | Sliding Puzzle | Hard |
| 775 | Global and Local Inversions | Medium |
| 777 | Swap Adjacent in LR String | Medium |
| 778 | Swim in Rising Water | Hard |
| 779 | K-th Symbol in Grammar | Medium |
| 780 | Reaching Points | Hard |
| 781 | Rabbits in Forest | Medium |
| 782 | Transform to Chessboard | Hard |
| 783 | Minimum Distance Between BST Nodes | Easy |
| 784 | Letter Case Permutation | Medium |
| 785 | Is Graph Bipartite? | Medium |
| 786 | K-th Smallest Prime Fraction | Medium |
| 787 | Cheapest Flights Within K Stops | Medium |
| 788 | Rotated Digits | Medium |
| 789 | Escape The Ghosts | Medium |
| 790 | Domino and Tromino Tiling | Medium |
| 791 | Custom Sort String | Medium |
| 792 | Number of Matching Subsequences | Medium |
| 793 | Preimage Size of Factorial Zeroes Function | Hard |
| 794 | Valid Tic-Tac-Toe State | Medium |
| 795 | Number of Subarrays with Bounded Maximum | Medium |
| 796 | Rotate String | Easy |
| 797 | All Paths From Source to Target | Medium |
| 798 | Smallest Rotation with Highest Score | Hard |
| 799 | Champagne Tower | Medium |
| 801 | Minimum Swaps To Make Sequences Increasing | Hard |
| 802 | Find Eventual Safe States | Medium |
| 803 | Bricks Falling When Hit | Hard |
| 804 | Unique Morse Code Words | Easy |
| 805 | Split Array With Same Average | Hard |
| 806 | Number of Lines To Write String | Easy |
| 808 | Soup Servings | Medium |
| 809 | Expressive Words | Medium |
| 810 | Chalkboard XOR Game | Hard |
| 811 | Subdomain Visit Count | Medium |
| 812 | Largest Triangle Area | Easy |
| 813 | Largest Sum of Averages | Medium |
| 814 | Binary Tree Pruning | Medium |
| 815 | Bus Routes | Hard |
| 816 | Ambiguous Coordinates | Medium |
| 817 | Linked List Components | Medium |
| 818 | Race Car | Hard |
| 819 | Most Common Word | Easy |
| 820 | Short Encoding of Words | Medium |
| 821 | Shortest Distance to a Character | Easy |
| 822 | Card Flipping Game | Medium |
| 823 | Binary Trees With Factors | Medium |
| 824 | Goat Latin | Easy |
| 825 | Friends Of Appropriate Ages | Medium |
| 826 | Most Profit Assigning Work | Medium |
| 827 | Making A Large Island | Hard |
| 828 | Count Unique Characters of All Substrings of a Given String | Hard |
| 829 | Consecutive Numbers Sum | Hard |
| 830 | Positions of Large Groups | Easy |
| 831 | Masking Personal Information | Medium |
| 833 | Find And Replace in String | Medium |
| 834 | Sum of Distances in Tree | Hard |
| 835 | Image Overlap | Medium |
| 836 | Rectangle Overlap | Easy |
| 837 | New 21 Game | Medium |
| 838 | Push Dominoes | Medium |
| 839 | Similar String Groups | Hard |
| 840 | Magic Squares In Grid | Medium |
| 841 | Keys and Rooms | Medium |
| 842 | Split Array into Fibonacci Sequence | Medium |
| 843 | Guess the Word | Hard |
| 844 | Backspace String Compare | Easy |
| 845 | Longest Mountain in Array | Medium |
| 846 | Hand of Straights | Medium |
| 847 | Shortest Path Visiting All Nodes | Hard |
| 848 | Shifting Letters | Medium |
| 849 | Maximize Distance to Closest Person | Medium |
| 850 | Rectangle Area II | Hard |
| 851 | Loud and Rich | Medium |
| 852 | Peak Index in a Mountain Array | Medium |
| 853 | Car Fleet | Medium |
| 854 | K-Similar Strings | Hard |
| 855 | Exam Room | Medium |
| 856 | Score of Parentheses | Medium |
| 857 | Minimum Cost to Hire K Workers | Hard |
| 858 | Mirror Reflection | Medium |
| 859 | Buddy Strings | Easy |
| 860 | Lemonade Change | Easy |
| 861 | Score After Flipping Matrix | Medium |
| 862 | Shortest Subarray with Sum at Least K | Hard |
| 863 | All Nodes Distance K in Binary Tree | Medium |
| 864 | Shortest Path to Get All Keys | Hard |
| 865 | Smallest Subtree with all the Deepest Nodes | Medium |
| 866 | Prime Palindrome | Medium |
| 867 | Transpose Matrix | Easy |
| 868 | Binary Gap | Easy |
| 869 | Reordered Power of 2 | Medium |
| 870 | Advantage Shuffle | Medium |
| 871 | Minimum Number of Refueling Stops | Hard |
| 872 | Leaf-Similar Trees | Easy |
| 873 | Length of Longest Fibonacci Subsequence | Medium |
| 874 | Walking Robot Simulation | Medium |
| 875 | Koko Eating Bananas | Medium |
| 876 | Middle of the Linked List | Easy |
| 877 | Stone Game | Medium |
| 878 | Nth Magical Number | Hard |
| 879 | Profitable Schemes | Hard |
| 880 | Decoded String at Index | Medium |
| 881 | Boats to Save People | Medium |
| 882 | Reachable Nodes In Subdivided Graph | Hard |
| 883 | Projection Area of 3D Shapes | Easy |
| 884 | Uncommon Words from Two Sentences | Easy |
| 885 | Spiral Matrix III | Medium |
| 886 | Possible Bipartition | Medium |
| 887 | Super Egg Drop | Hard |
| 888 | Fair Candy Swap | Easy |
| 889 | Construct Binary Tree from Preorder and Postorder Traversal | Medium |
| 890 | Find and Replace Pattern | Medium |
| 891 | Sum of Subsequence Widths | Hard |
| 892 | Surface Area of 3D Shapes | Easy |
| 893 | Groups of Special-Equivalent Strings | Medium |
| 894 | All Possible Full Binary Trees | Medium |
| 895 | Maximum Frequency Stack | Hard |
| 896 | Monotonic Array | Easy |
| 897 | Increasing Order Search Tree | Easy |
| 898 | Bitwise ORs of Subarrays | Medium |
| 899 | Orderly Queue | Hard |
| 900 | RLE Iterator | Medium |
| 901 | Online Stock Span | Medium |
| 902 | Numbers At Most N Given Digit Set | Hard |
| 903 | Valid Permutations for DI Sequence | Hard |
| 904 | Fruit Into Baskets | Medium |
| 905 | Sort Array By Parity | Easy |
| 906 | Super Palindromes | Hard |
| 907 | Sum of Subarray Minimums | Medium |
| 908 | Smallest Range I | Easy |
| 909 | Snakes and Ladders | Medium |
| 910 | Smallest Range II | Medium |
| 911 | Online Election | Medium |
| 912 | Sort an Array | Medium |
| 913 | Cat and Mouse | Hard |
| 914 | X of a Kind in a Deck of Cards | Medium |
| 915 | Partition Array into Disjoint Intervals | Medium |
| 916 | Word Subsets | Medium |
| 918 | Maximum Sum Circular Subarray | Medium |
| 919 | Complete Binary Tree Inserter | Medium |
| 920 | Number of Music Playlists | Hard |
| 921 | Minimum Add to Make Parentheses Valid | Medium |
| 922 | Sort Array By Parity II | Easy |
| 923 | 3Sum With Multiplicity | Medium |
| 924 | Minimize Malware Spread | Hard |
| 925 | Long Pressed Name | Easy |
| 926 | Flip String to Monotone Increasing | Medium |
| 927 | Three Equal Parts | Hard |
| 928 | Minimize Malware Spread II | Hard |
| 929 | Unique Email Addresses | Easy |
| 930 | Binary Subarrays With Sum | Medium |
| 931 | Minimum Falling Path Sum | Medium |
| 932 | Beautiful Array | Medium |
| 933 | Number of Recent Calls | Easy |
| 934 | Shortest Bridge | Medium |
| 935 | Knight Dialer | Medium |
| 936 | Stamping The Sequence | Hard |
| 937 | Reorder Data in Log Files | Medium |
| 938 | Range Sum of BST | Easy |
| 939 | Minimum Area Rectangle | Medium |
| 940 | Distinct Subsequences II | Hard |
| 941 | Valid Mountain Array | Easy |
| 942 | DI String Match | Easy |
| 943 | Find the Shortest Superstring | Hard |
| 944 | Delete Columns to Make Sorted | Easy |
| 945 | Minimum Increment to Make Array Unique | Medium |
| 946 | Validate Stack Sequences | Medium |
| 947 | Most Stones Removed with Same Row or Column | Medium |
| 948 | Bag of Tokens | Medium |
| 949 | Largest Time for Given Digits | Medium |
| 950 | Reveal Cards In Increasing Order | Medium |
| 951 | Flip Equivalent Binary Trees | Medium |
| 952 | Largest Component Size by Common Factor | Hard |
| 953 | Verifying an Alien Dictionary | Easy |
| 954 | Array of Doubled Pairs | Medium |
| 955 | Delete Columns to Make Sorted II | Medium |
| 956 | Tallest Billboard | Hard |
| 957 | Prison Cells After N Days | Medium |
| 958 | Check Completeness of a Binary Tree | Medium |
| 959 | Regions Cut By Slashes | Medium |
| 960 | Delete Columns to Make Sorted III | Hard |
| 962 | Maximum Width Ramp | Medium |
| 963 | Minimum Area Rectangle II | Medium |
| 964 | Least Operators to Express Number | Hard |
| 965 | Univalued Binary Tree | Easy |
| 966 | Vowel Spellchecker | Medium |
| 967 | Numbers With Same Consecutive Differences | Medium |
| 968 | Binary Tree Cameras | Hard |
| 969 | Pancake Sorting | Medium |
| 970 | Powerful Integers | Easy |
| 971 | Flip Binary Tree To Match Preorder Traversal | Medium |
| 972 | Equal Rational Numbers | Hard |
| 973 | K Closest Points to Origin | Medium |
| 974 | Subarray Sums Divisible by K | Medium |
| 975 | Odd Even Jump | Hard |
| 976 | Largest Perimeter Triangle | Easy |
| 977 | Squares of a Sorted Array | Easy |
| 978 | Longest Turbulent Subarray | Medium |
| 979 | Distribute Coins in Binary Tree | Medium |
| 980 | Unique Paths III | Hard |
| 981 | Time Based Key-Value Store | Medium |
| 982 | Triples with Bitwise AND Equal To Zero | Hard |
| 983 | Minimum Cost For Tickets | Medium |
| 984 | String Without AAA or BBB | Medium |
| 985 | Sum of Even Numbers After Queries | Easy |
| 986 | Interval List Intersections | Medium |
| 987 | Vertical Order Traversal of a Binary Tree | Hard |
| 988 | Smallest String Starting From Leaf | Medium |
| 989 | Add to Array-Form of Integer | Easy |
| 990 | Satisfiability of Equality Equations | Medium |
| 991 | Broken Calculator | Medium |
| 992 | Subarrays with K Different Integers | Hard |
| 993 | Cousins in Binary Tree | Easy |
| 994 | Rotting Oranges | Medium |
| 995 | Minimum Number of K Consecutive Bit Flips | Hard |
| 996 | Number of Squareful Arrays | Hard |
| 997 | Find the Town Judge | Easy |
| 998 | Maximum Binary Tree II | Medium |
| 999 | Available Captures for Rook | Easy |
| 1000 | Minimum Cost to Merge Stones | Hard |
| 1001 | Grid Illumination | Hard |
| 1002 | Find Common Characters | Easy |
| 1003 | Check If Word Is Valid After Substitutions | Medium |
| 1004 | Max Consecutive Ones III | Medium |
| 1005 | Maximize Sum Of Array After K Negations | Easy |
| 1006 | Clumsy Factorial | Medium |
| 1007 | Minimum Domino Rotations For Equal Row | Medium |
| 1008 | Construct Binary Search Tree from Preorder Traversal | Medium |
| 1009 | Complement of Base 10 Integer | Easy |
| 1010 | Pairs of Songs With Total Durations Divisible by 60 | Medium |
| 1011 | Capacity To Ship Packages Within D Days | Medium |
| 1012 | Numbers With Repeated Digits | Hard |
| 1013 | Partition Array Into Three Parts With Equal Sum | Easy |
| 1014 | Best Sightseeing Pair | Medium |
| 1015 | Smallest Integer Divisible by K | Medium |
| 1016 | Binary String With Substrings Representing 1 To N | Medium |
| 1017 | Convert to Base -2 | Medium |
| 1018 | Binary Prefix Divisible By 5 | Easy |
| 1019 | Next Greater Node In Linked List | Medium |
| 1020 | Number of Enclaves | Medium |
| 1022 | Sum of Root To Leaf Binary Numbers | Easy |
| 1023 | Camelcase Matching | Medium |
| 1024 | Video Stitching | Medium |
| 1025 | Divisor Game | Easy |
| 1026 | Maximum Difference Between Node and Ancestor | Medium |
| 1027 | Longest Arithmetic Subsequence | Medium |
| 1028 | Recover a Tree From Preorder Traversal | Hard |
| 1029 | Two City Scheduling | Medium |
| 1030 | Matrix Cells in Distance Order | Easy |
| 1031 | Maximum Sum of Two Non-Overlapping Subarrays | Medium |
| 1032 | Stream of Characters | Hard |
| 1033 | Moving Stones Until Consecutive | Medium |
| 1034 | Coloring A Border | Medium |
| 1035 | Uncrossed Lines | Medium |
| 1036 | Escape a Large Maze | Hard |
| 1037 | Valid Boomerang | Easy |
| 1038 | Binary Search Tree to Greater Sum Tree | Medium |
| 1039 | Minimum Score Triangulation of Polygon | Medium |
| 1040 | Moving Stones Until Consecutive II | Medium |
| 1041 | Robot Bounded In Circle | Medium |
| 1042 | Flower Planting With No Adjacent | Medium |
| 1043 | Partition Array for Maximum Sum | Medium |
| 1044 | Longest Duplicate Substring | Hard |
| 1046 | Last Stone Weight | Easy |
| 1047 | Remove All Adjacent Duplicates In String | Easy |
| 1048 | Longest String Chain | Medium |
| 1049 | Last Stone Weight II | Medium |
| 1051 | Height Checker | Easy |
| 1052 | Grumpy Bookstore Owner | Medium |
| 1053 | Previous Permutation With One Swap | Medium |
| 1054 | Distant Barcodes | Medium |
| 1061 | Lexicographically Smallest Equivalent String | Medium |
| 1071 | Greatest Common Divisor of Strings | Easy |
| 1072 | Flip Columns For Maximum Number of Equal Rows | Medium |
| 1073 | Adding Two Negabinary Numbers | Medium |
| 1074 | Number of Submatrices That Sum to Target | Hard |
| 1078 | Occurrences After Bigram | Easy |
| 1079 | Letter Tile Possibilities | Medium |
| 1080 | Insufficient Nodes in Root to Leaf Paths | Medium |
| 1081 | Smallest Subsequence of Distinct Characters | Medium |
| 1089 | Duplicate Zeros | Easy |
| 1090 | Largest Values From Labels | Medium |
| 1091 | Shortest Path in Binary Matrix | Medium |
| 1092 | Shortest Common Supersequence | Hard |
| 1093 | Statistics from a Large Sample | Medium |
| 1094 | Car Pooling | Medium |
| 1095 | Find in Mountain Array | Hard |
| 1096 | Brace Expansion II | Hard |
| 1103 | Distribute Candies to People | Easy |
| 1104 | Path In Zigzag Labelled Binary Tree | Medium |
| 1105 | Filling Bookcase Shelves | Medium |
| 1106 | Parsing A Boolean Expression | Hard |
| 1108 | Defanging an IP Address | Easy |
| 1109 | Corporate Flight Bookings | Medium |
| 1110 | Delete Nodes And Return Forest | Medium |
| 1111 | Maximum Nesting Depth of Two Valid Parentheses Strings | Medium |
| 1122 | Relative Sort Array | Easy |
| 1123 | Lowest Common Ancestor of Deepest Leaves | Medium |
| 1124 | Longest Well-Performing Interval | Medium |
| 1125 | Smallest Sufficient Team | Hard |
| 1128 | Number of Equivalent Domino Pairs | Easy |
| 1129 | Shortest Path with Alternating Colors | Medium |
| 1130 | Minimum Cost Tree From Leaf Values | Medium |
| 1131 | Maximum of Absolute Value Expression | Medium |
| 1137 | N-th Tribonacci Number | Easy |
| 1138 | Alphabet Board Path | Medium |
| 1139 | Largest 1-Bordered Square | Medium |
| 1140 | Stone Game II | Medium |
| 1143 | Longest Common Subsequence | Medium |
| 1144 | Decrease Elements To Make Array Zigzag | Medium |
| 1145 | Binary Tree Coloring Game | Medium |
| 1146 | Snapshot Array | Medium |
| 1147 | Longest Chunked Palindrome Decomposition | Hard |
| 1154 | Day of the Year | Easy |
| 1155 | Number of Dice Rolls With Target Sum | Medium |
| 1156 | Swap For Longest Repeated Character Substring | Medium |
| 1157 | Online Majority Element In Subarray | Hard |
| 1160 | Find Words That Can Be Formed by Characters | Easy |
| 1161 | Maximum Level Sum of a Binary Tree | Medium |
| 1162 | As Far from Land as Possible | Medium |
| 1163 | Last Substring in Lexicographical Order | Hard |
| 1169 | Invalid Transactions | Medium |
| 1170 | Compare Strings by Frequency of the Smallest Character | Medium |
| 1171 | Remove Zero Sum Consecutive Nodes from Linked List | Medium |
| 1172 | Dinner Plate Stacks | Hard |
| 1175 | Prime Arrangements | Easy |
| 1177 | Can Make Palindrome from Substring | Medium |
| 1178 | Number of Valid Words for Each Puzzle | Hard |
| 1184 | Distance Between Bus Stops | Easy |
| 1185 | Day of the Week | Easy |
| 1186 | Maximum Subarray Sum with One Deletion | Medium |
| 1187 | Make Array Strictly Increasing | Hard |
| 1189 | Maximum Number of Balloons | Easy |
| 1190 | Reverse Substrings Between Each Pair of Parentheses | Medium |
| 1191 | K-Concatenation Maximum Sum | Medium |
| 1192 | Critical Connections in a Network | Hard |
| 1200 | Minimum Absolute Difference | Easy |
| 1201 | Ugly Number III | Medium |
| 1202 | Smallest String With Swaps | Medium |
| 1203 | Sort Items by Groups Respecting Dependencies | Hard |
| 1206 | Design Skiplist | Hard |
| 1207 | Unique Number of Occurrences | Easy |
| 1208 | Get Equal Substrings Within Budget | Medium |
| 1209 | Remove All Adjacent Duplicates in String II | Medium |
| 1210 | Minimum Moves to Reach Target with Rotations | Hard |
| 1217 | Minimum Cost to Move Chips to The Same Position | Easy |
| 1218 | Longest Arithmetic Subsequence of Given Difference | Medium |
| 1219 | Path with Maximum Gold | Medium |
| 1220 | Count Vowels Permutation | Hard |
| 1222 | Queens That Can Attack the King | Medium |
| 1223 | Dice Roll Simulation | Hard |
| 1224 | Maximum Equal Frequency | Hard |
| 1227 | Airplane Seat Assignment Probability | Medium |
| 1232 | Check If It Is a Straight Line | Easy |
| 1233 | Remove Sub-Folders from the Filesystem | Medium |
| 1234 | Replace the Substring for Balanced String | Medium |
| 1235 | Maximum Profit in Job Scheduling | Hard |
| 1237 | Find Positive Integer Solution for a Given Equation | Medium |
| 1238 | Circular Permutation in Binary Representation | Medium |
| 1239 | Maximum Length of a Concatenated String with Unique Characters | Medium |
| 1240 | Tiling a Rectangle with the Fewest Squares | Hard |
| 1247 | Minimum Swaps to Make Strings Equal | Medium |
| 1248 | Count Number of Nice Subarrays | Medium |
| 1249 | Minimum Remove to Make Valid Parentheses | Medium |
| 1250 | Check If It Is a Good Array | Hard |
| 1252 | Cells with Odd Values in a Matrix | Easy |
| 1253 | Reconstruct a 2-Row Binary Matrix | Medium |
| 1254 | Number of Closed Islands | Medium |
| 1255 | Maximum Score Words Formed by Letters | Hard |
| 1260 | Shift 2D Grid | Easy |
| 1261 | Find Elements in a Contaminated Binary Tree | Medium |
| 1262 | Greatest Sum Divisible by Three | Medium |
| 1263 | Minimum Moves to Move a Box to Their Target Location | Hard |
| 1267 | Count Servers that Communicate | Medium |
| 1268 | Search Suggestions System | Medium |
| 1269 | Number of Ways to Stay in the Same Place After Some Steps | Hard |
| 1275 | Find Winner on a Tic Tac Toe Game | Easy |
| 1276 | Number of Burgers with No Waste of Ingredients | Medium |
| 1277 | Count Square Submatrices with All Ones | Medium |
| 1278 | Palindrome Partitioning III | Hard |
| 1284 | Minimum Number of Flips to Convert Binary Matrix to Zero Matrix | Hard |
| 1286 | Iterator for Combination | Medium |
| 1287 | Element Appearing More Than 25% In Sorted Array | Easy |
| 1288 | Remove Covered Intervals | Medium |
| 1289 | Minimum Falling Path Sum II | Hard |
| 1290 | Convert Binary Number in a Linked List to Integer | Easy |
| 1291 | Sequential Digits | Medium |
| 1292 | Maximum Side Length of a Square with Sum Less than or Equal to Threshold | Medium |
| 1293 | Shortest Path in a Grid with Obstacles Elimination | Hard |
| 1295 | Find Numbers with Even Number of Digits | Easy |
| 1296 | Divide Array in Sets of K Consecutive Numbers | Medium |
| 1297 | Maximum Number of Occurrences of a Substring | Medium |
| 1298 | Maximum Candies You Can Get from Boxes | Hard |
| 1299 | Replace Elements with Greatest Element on Right Side | Easy |
| 1300 | Sum of Mutated Array Closest to Target | Medium |
| 1301 | Number of Paths with Max Score | Hard |
| 1302 | Deepest Leaves Sum | Medium |
| 1304 | Find N Unique Integers Sum up to Zero | Easy |
| 1305 | All Elements in Two Binary Search Trees | Medium |
| 1306 | Jump Game III | Medium |
| 1307 | Verbal Arithmetic Puzzle | Hard |
| 1309 | Decrypt String from Alphabet to Integer Mapping | Easy |
| 1310 | XOR Queries of a Subarray | Medium |
| 1311 | Get Watched Videos by Your Friends | Medium |
| 1312 | Minimum Insertion Steps to Make a String Palindrome | Hard |
| 1313 | Decompress Run-Length Encoded List | Easy |
| 1314 | Matrix Block Sum | Medium |
| 1315 | Sum of Nodes with Even-Valued Grandparent | Medium |
| 1316 | Distinct Echo Substrings | Hard |
| 1317 | Convert Integer to the Sum of Two No-Zero Integers | Easy |
| 1318 | Minimum Flips to Make a OR b Equal to c | Medium |
| 1319 | Number of Operations to Make Network Connected | Medium |
| 1320 | Minimum Distance to Type a Word Using Two Fingers | Hard |
| 1323 | Maximum 69 Number | Easy |
| 1324 | Print Words Vertically | Medium |
| 1325 | Delete Leaves With a Given Value | Medium |
| 1326 | Minimum Number of Taps to Open to Water a Garden | Hard |
| 1328 | Break a Palindrome | Medium |
| 1329 | Sort the Matrix Diagonally | Medium |
| 1330 | Reverse Subarray To Maximize Array Value | Hard |
| 1331 | Rank Transform of an Array | Easy |
| 1332 | Remove Palindromic Subsequences | Easy |
| 1333 | Filter Restaurants by Vegan-Friendly, Price and Distance | Medium |
| 1334 | Find the City With the Smallest Number of Neighbors at a Threshold Distance | Medium |
| 1335 | Minimum Difficulty of a Job Schedule | Hard |
| 1337 | The K Weakest Rows in a Matrix | Easy |
| 1338 | Reduce Array Size to The Half | Medium |
| 1339 | Maximum Product of Splitted Binary Tree | Medium |
| 1340 | Jump Game V | Hard |
| 1342 | Number of Steps to Reduce a Number to Zero | Easy |
| 1343 | Number of Sub-arrays of Size K and Average Greater than or Equal to Threshold | Medium |
| 1344 | Angle Between Hands of a Clock | Medium |
| 1345 | Jump Game IV | Hard |
| 1346 | Check If N and Its Double Exist | Easy |
| 1347 | Minimum Number of Steps to Make Two Strings Anagram | Medium |
| 1348 | Tweet Counts Per Frequency | Medium |
| 1349 | Maximum Students Taking Exam | Hard |
| 1351 | Count Negative Numbers in a Sorted Matrix | Easy |
| 1352 | Product of the Last K Numbers | Medium |
| 1353 | Maximum Number of Events That Can Be Attended | Medium |
| 1354 | Construct Target Array With Multiple Sums | Hard |
| 1356 | Sort Integers by The Number of 1 Bits | Easy |
| 1357 | Apply Discount Every n Orders | Medium |
| 1358 | Number of Substrings Containing All Three Characters | Medium |
| 1359 | Count All Valid Pickup and Delivery Options | Hard |
| 1360 | Number of Days Between Two Dates | Easy |
| 1361 | Validate Binary Tree Nodes | Medium |
| 1362 | Closest Divisors | Medium |
| 1363 | Largest Multiple of Three | Hard |
| 1365 | How Many Numbers Are Smaller Than the Current Number | Easy |
| 1366 | Rank Teams by Votes | Medium |
| 1367 | Linked List in Binary Tree | Medium |
| 1368 | Minimum Cost to Make at Least One Valid Path in a Grid | Hard |
| 1370 | Increasing Decreasing String | Easy |
| 1371 | Find the Longest Substring Containing Vowels in Even Counts | Medium |
| 1372 | Longest ZigZag Path in a Binary Tree | Medium |
| 1373 | Maximum Sum BST in Binary Tree | Hard |
| 1374 | Generate a String With Characters That Have Odd Counts | Easy |
| 1375 | Number of Times Binary String Is Prefix-Aligned | Medium |
| 1376 | Time Needed to Inform All Employees | Medium |
| 1377 | Frog Position After T Seconds | Hard |
| 1379 | Find a Corresponding Node of a Binary Tree in a Clone of That Tree | Easy |
| 1380 | Lucky Numbers in a Matrix | Easy |
| 1381 | Design a Stack With Increment Operation | Medium |
| 1382 | Balance a Binary Search Tree | Medium |
| 1383 | Maximum Performance of a Team | Hard |
| 1385 | Find the Distance Value Between Two Arrays | Easy |
| 1386 | Cinema Seat Allocation | Medium |
| 1387 | Sort Integers by The Power Value | Medium |
| 1388 | Pizza With 3n Slices | Hard |
| 1389 | Create Target Array in the Given Order | Easy |
| 1390 | Four Divisors | Medium |
| 1391 | Check if There is a Valid Path in a Grid | Medium |
| 1392 | Longest Happy Prefix | Hard |
| 1394 | Find Lucky Integer in an Array | Easy |
| 1395 | Count Number of Teams | Medium |
| 1396 | Design Underground System | Medium |
| 1397 | Find All Good Strings | Hard |
| 1399 | Count Largest Group | Easy |
| 1400 | Construct K Palindrome Strings | Medium |
| 1401 | Circle and Rectangle Overlapping | Medium |
| 1402 | Reducing Dishes | Hard |
| 1403 | Minimum Subsequence in Non-Increasing Order | Easy |
| 1404 | Number of Steps to Reduce a Number in Binary Representation to One | Medium |
| 1405 | Longest Happy String | Medium |
| 1406 | Stone Game III | Hard |
| 1408 | String Matching in an Array | Easy |
| 1409 | Queries on a Permutation With Key | Medium |
| 1410 | HTML Entity Parser | Medium |
| 1411 | Number of Ways to Paint N × 3 Grid | Hard |
| 1413 | Minimum Value to Get Positive Step by Step Sum | Easy |
| 1414 | Find the Minimum Number of Fibonacci Numbers Whose Sum Is K | Medium |
| 1415 | The k-th Lexicographical String of All Happy Strings of Length n | Medium |
| 1416 | Restore The Array | Hard |
| 1417 | Reformat The String | Easy |
| 1418 | Display Table of Food Orders in a Restaurant | Medium |
| 1419 | Minimum Number of Frogs Croaking | Medium |
| 1420 | Build Array Where You Can Find The Maximum Exactly K Comparisons | Hard |
| 1422 | Maximum Score After Splitting a String | Easy |
| 1423 | Maximum Points You Can Obtain from Cards | Medium |
| 1424 | Diagonal Traverse II | Medium |
| 1425 | Constrained Subsequence Sum | Hard |
| 1431 | Kids With the Greatest Number of Candies | Easy |
| 1432 | Max Difference You Can Get From Changing an Integer | Medium |
| 1433 | Check If a String Can Break Another String | Medium |
| 1434 | Number of Ways to Wear Different Hats to Each Other | Hard |
| 1436 | Destination City | Easy |
| 1437 | Check If All 1's Are at Least Length K Places Away | Easy |
| 1438 | Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit | Medium |
| 1439 | Find the Kth Smallest Sum of a Matrix With Sorted Rows | Hard |
| 1441 | Build an Array With Stack Operations | Medium |
| 1442 | Count Triplets That Can Form Two Arrays of Equal XOR | Medium |
| 1443 | Minimum Time to Collect All Apples in a Tree | Medium |
| 1444 | Number of Ways of Cutting a Pizza | Hard |
| 1446 | Consecutive Characters | Easy |
| 1447 | Simplified Fractions | Medium |
| 1448 | Count Good Nodes in Binary Tree | Medium |
| 1449 | Form Largest Integer With Digits That Add up to Target | Hard |
| 1450 | Number of Students Doing Homework at a Given Time | Easy |
| 1451 | Rearrange Words in a Sentence | Medium |
| 1452 | People Whose List of Favorite Companies Is Not a Subset of Another List | Medium |
| 1453 | Maximum Number of Darts Inside of a Circular Dartboard | Hard |
| 1455 | Check If a Word Occurs As a Prefix of Any Word in a Sentence | Easy |
| 1456 | Maximum Number of Vowels in a Substring of Given Length | Medium |
| 1457 | Pseudo-Palindromic Paths in a Binary Tree | Medium |
| 1458 | Max Dot Product of Two Subsequences | Hard |
| 1460 | Make Two Arrays Equal by Reversing Sub-arrays | Easy |
| 1461 | Check If a String Contains All Binary Codes of Size K | Medium |
| 1462 | Course Schedule IV | Medium |
| 1463 | Cherry Pickup II | Hard |
| 1464 | Maximum Product of Two Elements in an Array | Easy |
| 1466 | Reorder Routes to Make All Paths Lead to the City Zero | Medium |
| 1470 | Shuffle the Array | Easy |
| 1472 | Design Browser History | Medium |
| 1475 | Final Prices With a Special Discount in a Shop | Easy |
| 1480 | Running Sum of 1d Array | Easy |
| 1481 | Least Number of Unique Integers after K Removals | Medium |
| 1486 | XOR Operation in an Array | Easy |
| 1491 | Average Salary Excluding the Minimum and Maximum Salary | Easy |
| 1492 | The kth Factor of n | Medium |
| 1493 | Longest Subarray of 1's After Deleting One Element | Medium |
| 1496 | Path Crossing | Easy |
| 1502 | Can Make Arithmetic Progression From Sequence | Easy |
| 1507 | Reformat Date | Easy |
| 1512 | Number of Good Pairs | Easy |
| 1519 | Number of Nodes in the Sub-Tree With the Same Label | Medium |
| 1524 | Number of Sub-arrays With Odd Sum | Medium |
| 1528 | Shuffle String | Easy |
| 1534 | Count Good Triplets | Easy |
| 1535 | Find the Winner of an Array Game | Medium |
| 1550 | Three Consecutive Odds | Easy |
| 1551 | Minimum Operations to Make Array Equal | Medium |
| 1566 | Detect Pattern of Length M Repeated K or More Times | Easy |
| 1576 | Replace All ?'s to Avoid Consecutive Repeating Characters | Medium |
| 1598 | Crawler Log Folder | Easy |
| 1657 | Determine if Two Strings Are Close | Medium |
| 1668 | Maximum Repeating Substring | Easy |
| 1669 | Merge In Between Linked Lists | Medium |
| 1672 | Richest Customer Wealth | Easy |
| 1679 | Max Number of K-Sum Pairs | Medium |
| 1716 | Calculate Money in Leetcode Bank | Easy |
| 1718 | Construct the Lexicographically Largest Valid Sequence | Medium |
| 1726 | Tuple with Same Product | Medium |
| 1732 | Find the Highest Altitude | Easy |
| 1748 | Sum of Unique Elements | Easy |
| 1749 | Maximum Absolute Sum of Any Subarray | Medium |
| 1752 | Check if Array Is Sorted and Rotated | Easy |
| 1764 | Form Array by Concatenating Subarrays of Another Array | Medium |
| 1765 | Map of Highest Peak | Medium |
| 1768 | Merge Strings Alternately | Easy |
| 1769 | Minimum Number of Operations to Move All Balls to Each Box | Medium |
| 1780 | Check if Number is a Sum of Powers of Three | Medium |
| 1790 | Check if One String Swap Can Make Strings Equal | Easy |
| 1791 | Find Center of Star Graph | Easy |
| 1800 | Maximum Ascending Subarray Sum | Easy |
| 1812 | Determine Color of a Chessboard Square | Easy |
| 1817 | Finding the Users Active Minutes | Medium |
| 1832 | Check if the Sentence Is Pangram | Easy |
| 1833 | Maximum Ice Cream Bars | Medium |
| 1863 | Sum of All Subset XOR Totals | Easy |
| 1880 | Check if Word Equals Summation of Two Words | Easy |
| 1886 | Determine Whether Matrix Can Be Obtained By Rotation | Easy |
| 1910 | Remove All Occurrences of a Substring | Medium |
| 1920 | Build Array from Permutation | Easy |
| 1922 | Count Good Numbers | Medium |
| 1926 | Nearest Exit from Entrance in Maze | Medium |
| 1929 | Concatenation of Array | Easy |
| 1930 | Unique Length-3 Palindromic Subsequences | Medium |
| 1935 | Maximum Number of Words You Can Type | Easy |
| 1976 | Number of Ways to Arrive at Destination | Medium |
| 1980 | Find Unique Binary String | Medium |
| 1985 | Find the Kth Largest Integer in the Array | Medium |
| 1996 | The Number of Weak Characters in the Game | Medium |
| 2000 | Reverse Prefix of Word | Easy |
| 2011 | Final Value of Variable After Performing Operations | Easy |
| 2016 | Maximum Difference Between Increasing Elements | Easy |
| 2017 | Grid Game | Medium |
| 2027 | Minimum Moves to Convert String | Easy |
| 2033 | Minimum Operations to Make a Uni-Value Grid | Medium |
| 2037 | Minimum Number of Moves to Seat Everyone | Easy |
| 2047 | Number of Valid Words in a Sentence | Easy |
| 2053 | Kth Distinct String in an Array | Medium |
| 2085 | Count Common Words With One Occurrence | Easy |
| 2095 | Delete the Middle Node of a Linked List | Medium |
| 2099 | Find Subsequence of Length K With the Largest Sum | Medium |
| 2114 | Maximum Number of Words Found in Sentences | Easy |
| 2115 | Find All Possible Recipes from Given Supplies | Medium |
| 2116 | Check if a Parentheses String Can Be Valid | Medium |
| 2127 | Maximum Employees to Be Invited to a Meeting | Hard |
| 2129 | Capitalize the Title | Easy |
| 2130 | Maximum Twin Sum of a Linked List | Medium |
| 2140 | Solving Questions With Brainpower | Medium |
| 2154 | Keep Multiplying Found Values by Two | Easy |
| 2161 | Partition Array According to Given Pivot | Medium |
| 2179 | Count Good Triplets in an Array | Hard |
| 2185 | Counting Words With a Given Prefix | Easy |
| 2206 | Divide Array Into Equal Pairs | Easy |
| 2215 | Find the Difference of Two Arrays | Easy |
| 2226 | Maximum Candies Allocated to K Children | Medium |
| 2235 | Add Two Integers | Easy |
| 2244 | Minimum Rounds to Complete All Tasks | Medium |
| 2270 | Number of Ways to Split Array | Medium |
| 2300 | Successful Pairs of Spells and Potions | Medium |
| 2336 | Smallest Number in Infinite Set | Medium |
| 2342 | Max Sum of a Pair With Equal Sum of Digits | Medium |
| 2349 | Design a Number Container System | Medium |
| 2352 | Equal Row and Column Pairs | Medium |
| 2364 | Count Number of Bad Pairs | Medium |
| 2375 | Construct Smallest Number From DI String | Medium |
| 2379 | Minimum Recolors to Get K Consecutive Black Blocks | Easy |
| 2381 | Shifting Letters II | Medium |
| 2390 | Removing Stars From a String | Medium |
| 2396 | Strictly Palindromic Number | Medium |
| 2401 | Longest Nice Subarray | Medium |
| 2413 | Smallest Even Multiple | Easy |
| 2425 | Bitwise XOR of All Pairings | Medium |
| 2427 | Number of Common Factors | Easy |
| 2429 | Minimize XOR | Medium |
| 2460 | Apply Operations to an Array | Easy |
| 2462 | Total Cost to Hire K Workers | Medium |
| 2467 | Most Profitable Path in a Tree | Medium |
| 2469 | Convert the Temperature | Easy |
| 2482 | Difference Between Ones and Zeros in Row and Column | Medium |
| 2490 | Circular Sentence | Easy |
| 2493 | Divide Nodes Into the Maximum Number of Groups | Hard |
| 2503 | Maximum Number of Points From Grid Queries | Hard |
| 2523 | Closest Prime Numbers in Range | Medium |
| 2529 | Maximum Count of Positive Integer and Negative Integer | Easy |
| 2535 | Difference Between Element Sum and Digit Sum of an Array | Easy |
| 2542 | Maximum Subsequence Score | Medium |
| 2551 | Put Marbles in Bags | Hard |
| 2559 | Count Vowel Strings in Ranges | Medium |
| 2560 | House Robber IV | Medium |
| 2570 | Merge Two 2D Arrays by Summing Values | Easy |
| 2579 | Count Total Number of Colored Cells | Medium |
| 2594 | Minimum Time to Repair Cars | Medium |
| 2618 | Check if Object Instance of Class | Medium |
| 2619 | Array Prototype Last | Easy |
| 2620 | Counter | Easy |
| 2621 | Sleep | Easy |
| 2622 | Cache With Time Limit | Medium |
| 2623 | Memoize | Medium |
| 2625 | Flatten Deeply Nested Array | Medium |
| 2626 | Array Reduce Transformation | Easy |
| 2627 | Debounce | Medium |
| 2629 | Function Composition | Easy |
| 2630 | Memoize II | Hard |
| 2631 | Group By | Medium |
| 2634 | Filter Elements from Array | Easy |
| 2635 | Apply Transform Over Each Element in Array | Easy |
| 2637 | Promise Time Limit | Medium |
| 2648 | Generate Fibonacci Sequence | Easy |
| 2649 | Nested Array Generator | Medium |
| 2650 | Design Cancellable Function | Hard |
| 2657 | Find the Prefix Common Array of Two Arrays | Medium |
| 2658 | Maximum Number of Fish in a Grid | Medium |
| 2661 | First Completely Painted Row or Column | Medium |
| 2665 | Counter II | Easy |
| 2666 | Allow One Function Call | Easy |
| 2667 | Create Hello World Function | Easy |
| 2677 | Chunk Array | Easy |
| 2683 | Neighboring Bitwise XOR | Medium |
| 2685 | Count the Number of Complete Components | Medium |
| 2693 | Call Function with Custom Context | Medium |
| 2694 | Event Emitter | Medium |
| 2695 | Array Wrapper | Easy |
| 2698 | Find the Punishment Number of an Integer | Medium |
| 2703 | Return Length of Arguments Passed | Easy |
| 2704 | To Be Or Not To Be | Easy |
| 2705 | Compact Object | Medium |
| 2715 | Timeout Cancellation | Easy |
| 2721 | Execute Asynchronous Functions in Parallel | Medium |
| 2722 | Join Two Arrays by ID | Medium |
| 2723 | Add Two Promises | Easy |
| 2724 | Sort By | Easy |
| 2725 | Interval Cancellation | Easy |
| 2726 | Calculator with Method Chaining | Easy |
| 2727 | Is Object Empty | Easy |
| 2780 | Minimum Index of a Valid Split | Medium |
| 2818 | Apply Operations to Maximize Score | Hard |
| 2843 | Count Symmetric Integers | Easy |
| 2873 | Maximum Value of an Ordered Triplet I | Easy |
| 2874 | Maximum Value of an Ordered Triplet II | Medium |
| 2948 | Make Lexicographically Smallest Array by Swapping Elements | Medium |
| 2965 | Find Missing and Repeated Values | Easy |
| 2999 | Count the Number of Powerful Integers | Hard |
| 3042 | Count Prefix and Suffix Pairs I | Easy |
| 3066 | Minimum Operations to Exceed Threshold Value II | Medium |
| 3105 | Longest Strictly Increasing or Strictly Decreasing Subarray | Easy |
| 3108 | Minimum Cost Walk in Weighted Graph | Hard |
| 3110 | Score of a String | Easy |
| 3151 | Special Array I | Easy |
| 3160 | Find the Number of Distinct Colors Among the Balls | Medium |
| 3169 | Count Days Without Meetings | Medium |
| 3174 | Clear Digits | Easy |
| 3191 | Minimum Operations to Make Binary Array Elements Equal to One I | Medium |
| 3208 | Alternating Groups II | Medium |
| 3223 | Minimum Length of String After Operations | Medium |
| 3272 | Find the Count of Good Integers | Hard |
| 3306 | Count of Substrings Containing Every Vowel and K Consonants II | Medium |
| 3356 | Zero Array Transformation II | Medium |
| 3375 | Minimum Operations to Make Array Values Equal to K | Easy |
| 3392 | Count Subarrays of Length Three With a Condition | Easy |
| 3394 | Check if Grid can be Cut into Sections | Medium |
| 3396 | Minimum Number of Operations to Make Elements in Array Distinct | Easy |
| 3397 | Maximum Number of Distinct Elements After Operations | Medium |
| 3402 | Minimum Operations to Make Columns Strictly Increasing | Easy |
| 3452 | Sum of Good Numbers | Easy |
| 3461 | Check If Digits Are Equal in String After Operations I | Easy |
| 3462 | Maximum Sum With at Most K Elements | Medium |
| 3463 | Check If Digits Are Equal in String After Operations II | Hard |
| 3464 | Maximize the Distance Between Points on a Square | Hard |