LeetCode 目录
| # | Title | Difficulty |
|---|---|---|
| 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 | Search for a Range | Medium |
| 35 | Search Insert Position | Easy |
| 36 | Valid Sudoku | Medium |
| 37 | Sudoku Solver | Hard |
| 38 | Count and Say | Easy |
| 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 | Hard |
| 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 | Hard |
| 58 | Length of Last Word | Easy |
| 59 | Spiral Matrix II | Medium |
| 60 | Permutation Sequence | Medium |
| 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) | Easy |
| 70 | Climbing Stairs | Easy |
| 71 | Simplify Path | Medium |
| 72 | Edit Distance | Hard |
| 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 | Medium |
| 95 | Unique Binary Search Trees II | Medium |
| 96 | Unique Binary Search Trees | Medium |
| 97 | Interleaving String | Hard |
| 98 | Validate Binary Search Tree | Medium |
| 99 | Recover Binary Search Tree | Hard |
| 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 | Easy |
| 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 | Easy |
| 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 | Medium |
| 128 | Longest Consecutive Sequence | Hard |
| 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 | Medium |
| 145 | Binary Tree Postorder Traversal | Hard |
| 146 | LRU Cache | Hard |
| 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 | Easy |
| 156 | Binary Tree Upside Down | Medium |
| 157 | Read N Characters Given Read4 | Easy |
| 158 | Read N Characters Given Read4 II - Call multiple times | Hard |
| 159 | Longest Substring with At Most Two Distinct Characters | Hard |
| 160 | Intersection of Two Linked Lists | Easy |
| 161 | One Edit Distance | Medium |
| 162 | Find Peak Element | Medium |
| 163 | Missing Ranges | Medium |
| 164 | Maximum Gap | Hard |
| 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 |
| 170 | Two Sum III - Data structure design | Easy |
| 171 | Excel Sheet Column Number | Easy |
| 172 | Factorial Trailing Zeroes | Easy |
| 173 | Binary Search Tree Iterator | Medium |
| 174 | Dungeon Game | Hard |
| 175 | Combine Two Tables | Easy |
| 176 | Second Highest Salary | Easy |
| 177 | Nth Highest Salary | Medium |
| 178 | Rank Scores | Medium |
| 179 | Largest Number | Medium |
| 180 | Consecutive Numbers | Medium |
| 181 | Employees Earning More Than Their Managers | Easy |
| 182 | Duplicate Emails | Easy |
| 183 | Customers Who Never Order | Easy |
| 184 | Department Highest Salary | Medium |
| 185 | Department Top Three Salaries | Hard |
| 186 | Reverse Words in a String II | Medium |
| 187 | Repeated DNA Sequences | Medium |
| 188 | Best Time to Buy and Sell Stock IV | Hard |
| 189 | Rotate Array | Easy |
| 190 | Reverse Bits | Easy |
| 191 | Number of 1 Bits | Easy |
| 192 | Word Frequency | Medium |
| 193 | Valid Phone Numbers | Easy |
| 194 | Transpose File | Medium |
| 195 | Tenth Line | Easy |
| 196 | Delete Duplicate Emails | Easy |
| 197 | Rising Temperature | Easy |
| 198 | House Robber | Easy |
| 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 | Easy |
| 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 | Add and Search Word - Data structure design | 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 | Medium |
| 221 | Maximal Square | Medium |
| 222 | Count Complete Tree Nodes | Medium |
| 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 | Medium |
| 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 |
| 243 | Shortest Word Distance | Easy |
| 244 | Shortest Word Distance II | Medium |
| 245 | Shortest Word Distance III | Medium |
| 246 | Strobogrammatic Number | Easy |
| 247 | Strobogrammatic Number II | Medium |
| 248 | Strobogrammatic Number III | Hard |
| 249 | Group Shifted Strings | Medium |
| 250 | Count Univalue Subtrees | Medium |
| 251 | Flatten 2D Vector | Medium |
| 252 | Meeting Rooms | Easy |
| 253 | Meeting Rooms II | Medium |
| 254 | Factor Combinations | Medium |
| 255 | Verify Preorder Sequence in Binary Search Tree | Medium |
| 256 | Paint House | Easy |
| 257 | Binary Tree Paths | Easy |
| 258 | Add Digits | Easy |
| 259 | 3Sum Smaller | Medium |
| 260 | Single Number III | Medium |
| 261 | Graph Valid Tree | Medium |
| 262 | Trips and Users | Hard |
| 263 | Ugly Number | Easy |
| 264 | Ugly Number II | Medium |
| 265 | Paint House II | Hard |
| 266 | Palindrome Permutation | Easy |
| 267 | Palindrome Permutation II | Medium |
| 268 | Missing Number | Easy |
| 269 | Alien Dictionary | Hard |
| 270 | Closest Binary Search Tree Value | Easy |
| 271 | Encode and Decode Strings | Medium |
| 272 | Closest Binary Search Tree Value II | Hard |
| 273 | Integer to English Words | Hard |
| 274 | H-Index | Medium |
| 275 | H-Index II | Medium |
| 276 | Paint Fence | Easy |
| 277 | Find the Celebrity | Medium |
| 278 | First Bad Version | Easy |
| 279 | Perfect Squares | Medium |
| 280 | Wiggle Sort | Medium |
| 281 | Zigzag Iterator | Medium |
| 282 | Expression Add Operators | Hard |
| 283 | Move Zeroes | Easy |
| 284 | Peeking Iterator | Medium |
| 285 | Inorder Successor in BST | Medium |
| 286 | Walls and Gates | Medium |
| 287 | Find the Duplicate Number | Medium |
| 288 | Unique Word Abbreviation | Medium |
| 289 | Game of Life | Medium |
| 290 | Word Pattern | Easy |
| 291 | Word Pattern II | Hard |
| 292 | Nim Game | Easy |
| 293 | Flip Game | Easy |
| 294 | Flip Game II | Medium |
| 295 | Find Median from Data Stream | Hard |
| 296 | Best Meeting Point | Hard |
| 297 | Serialize and Deserialize Binary Tree | Hard |
| 298 | Binary Tree Longest Consecutive Sequence | Medium |
| 299 | Bulls and Cows | Medium |
| 300 | Longest Increasing Subsequence | Medium |
| 301 | Remove Invalid Parentheses | Hard |
| 302 | Smallest Rectangle Enclosing Black Pixels | Hard |
| 303 | Range Sum Query - Immutable | Easy |
| 304 | Range Sum Query 2D - Immutable | Medium |
| 305 | Number of Islands II | Hard |
| 306 | Additive Number | Medium |
| 307 | Range Sum Query - Mutable | Medium |
| 308 | Range Sum Query 2D - Mutable | Hard |
| 309 | [Best Time to Buy and Sell Stock with Cooldown] | Medium |
| 310 | [Minimum Height Trees] | Medium |
| 311 | Sparse Matrix Multiplication | Medium |
| 312 | [Burst Balloons] | Hard |
| 313 | Super Ugly Number | Medium |
| 314 | Binary Tree Vertical Order Traversal | Medium |
| 315 | Count of Smaller Numbers After Self | Hard |
| 316 | [Remove Duplicate Letters] | Hard |
| 317 | Shortest Distance from All Buildings | Hard |
| 318 | Maximum Product of Word Lengths | Medium |
| 319 | Bulb Switcher | Medium |
| 320 | Generalized Abbreviation | Medium |
| 321 | Create Maximum Number | Hard |
| 322 | Coin Change | Medium |
| 323 | Number of Connected Components in an Undirected Graph | Medium |
| 324 | Wiggle Sort II | Medium |
| 325 | Maximum Size Subarray Sum Equals k | 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 | Medium |
| 333 | Largest BST Subtree | Medium |
| 334 | Increasing Triplet Subsequence | Medium |
| 335 | Self Crossing | Hard |
| 336 | Palindrome Pairs | Hard |
| 337 | House Robber III | Medium |
| 338 | Counting Bits | Medium |
| 339 | Nested List Weight Sum | Easy |
| 340 | Longest Substring with At Most K Distinct Characters | Hard |
| 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 |
| 346 | Moving Average from Data Stream | Easy |
| 347 | Top K Frequent Elements | Medium |
| 348 | Design Tic-Tac-Toe | Medium |
| 349 | Intersection of Two Arrays | Easy |
| 350 | Intersection of Two Arrays II | Easy |
| 351 | Android Unlock Patterns | Medium |
| 352 | Data Stream as Disjoint Intervals | Hard |
| 353 | Design Snake Game | Medium |
| 354 | Russian Doll Envelopes | Hard |
| 355 | Design Twitter | Medium |
| 356 | Line Reflection | Medium |
| 357 | Count Numbers with Unique Digits | Medium |
| 358 | Rearrange String k Distance Apart | Hard |
| 359 | Logger Rate Limiter | Easy |
| 360 | Sort Transformed Array | Medium |
| 361 | Bomb Enemy | Medium |
| 362 | Design Hit Counter | Medium |
| 363 | Max Sum of Rectangle No Larger Than K | Hard |
| 364 | Nested List Weight Sum II | Medium |
| 365 | Water and Jug Problem | Medium |
| 366 | Find Leaves of Binary Tree | Medium |
| 367 | Valid Perfect Square | Easy |
| 368 | Largest Divisible Subset | Medium |
| 369 | Plus One Linked List | Medium |
| 370 | Range Addition | Medium |
| 371 | Sum of Two Integers | Easy |
| 372 | Super Pow | Medium |
| 373 | Find K Pairs with Smallest Sums | Medium |
| 374 | Guess Number Higher or Lower | Easy |
| 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 |
| 379 | Design Phone Directory | 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 | Medium |
| 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 | Easy |
| 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 |
| 408 | Valid Word Abbreviation | Easy |
| 409 | Longest Palindrome | Easy |
| 410 | Split Array Largest Sum | Hard |
| 411 | Minimum Unique Word Abbreviation | 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 |
| 418 | Sentence Screen Fitting | Medium |
| 419 | Battleships in a Board | Medium |
| 420 | Strong Password Checker | Hard |
| 421 | Maximum XOR of Two Numbers in an Array | Medium |
| 422 | Valid Word Square | Easy |
| 423 | Reconstruct Original Digits from English | Medium |
| 424 | Longest Repeating Character Replacement | Medium |
| 425 | Word Squares | Hard |
| 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 | Easy |
| 438 | Find All Anagrams in a String | Easy |
| 439 | Ternary Expression Parser | Medium |
| 440 | K-th Smallest in Lexicographical Order | Hard |
| 441 | Arranging Coins | Easy |
| 442 | Find All Duplicates in an Array | Medium |
| 443 | String Compression | Easy |
| 444 | Sequence Reconstruction | Medium |
| 445 | Add Two Numbers II | Medium |
| 446 | Arithmetic Slices II - Subsequence | Hard |
| 447 | Number of Boomerangs | Easy |
| 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 | Easy |
| 454 | 4Sum II | Medium |
| 455 | Assign Cookies | Easy |
| 456 | 132 Pattern | Medium |
| 457 | Circular Array Loop | Medium |
| 458 | Poor Pigs | Easy |
| 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 | Easy |
| 464 | Can I Win | Medium |
| 465 | Optimal Account Balancing | Hard |
| 466 | Count The Repetitions | Hard |
| 467 | Unique Substrings in Wraparound String | Medium |
| 468 | Validate IP Address | Medium |
| 469 | Convex Polygon | Medium |
| 471 | Encode String with Shortest Length | Hard |
| 472 | Concatenated Words | Hard |
| 473 | Matchsticks to Square | Medium |
| 474 | Ones and Zeroes | Medium |
| 475 | Heaters | Easy |
| 476 | Number Complement | Easy |
| 477 | Total Hamming Distance | Medium |
| 479 | Largest Palindrome Product | Easy |
| 480 | Sliding Window Median | Hard |
| 481 | Magical String | Medium |
| 482 | License Key Formatting | Easy |
| 483 | Smallest Good Base | Hard |
| 484 | Find Permutation | Medium |
| 485 | Max Consecutive Ones | Easy |
| 486 | Predict the Winner | Medium |
| 487 | Max Consecutive Ones II | Medium |
| 488 | Zuma Game | Hard |
| 490 | The Maze | Medium |
| 491 | Increasing Subsequences | Medium |
| 492 | Construct the Rectangle | Easy |
| 493 | Reverse Pairs | Hard |
| 494 | Target Sum | Medium |
| 495 | Teemo Attacking | Medium |
| 496 | Next Greater Element I | Easy |
| 498 | Diagonal Traverse | Medium |
| 499 | The Maze III | Hard |
| 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 |
| 505 | The Maze II | Medium |
| 506 | Relative Ranks | Easy |
| 507 | Perfect Number | Easy |
| 508 | Most Frequent Subtree Sum | Medium |
| 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 2 | Medium |
| 520 | Detect Capital | Easy |
| 521 | Longest Uncommon Subsequence IÊ | 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 |
| 527 | Word Abbreviation | Hard |
| 529 | Minesweeper | Medium |
| 530 | Minimum Absolute Difference in BST | Easy |
| 531 | Lonely Pixel I | Medium |
| 532 | K-diff Pairs in an Array | Easy |
| 533 | Lonely Pixel II | Medium |
| 534 | Design TinyURL | Medium |
| 535 | Encode and Decode TinyURL | Medium |
| 536 | Construct Binary Tree from String | Medium |
| 537 | Complex Number Multiplication | Medium |
| 538 | Convert BST to Greater Tree | Easy |
| 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 |
| 544 | Output Contest Matches | Medium |
| 545 | Boundary of Binary Tree | Medium |
| 546 | Remove Boxes | Hard |
| 547 | Friend Circles | Medium |
| 548 | Split Array with Equal Sum | Medium |
| 549 | Binary Tree Longest Consecutive Sequence II | Medium |
| 551 | Student Attendance Record I | Easy |
| 552 | Student Attendance Record II | Hard |
| 553 | Optimal Division | Medium |
| 554 | Brick Wall | Medium |
| 555 | Split Concatenated Strings | Medium |
| 556 | Next Greater Element III | Medium |
| 557 | Reverse Words in a String III | Easy |
| 560 | Subarray Sum Equals K | Medium |
| 561 | Array Partition I | Easy |
| 562 | Longest Line of Consecutive One in Matrix | 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 |
| 568 | Maximum Vacation Days | Hard |
| 569 | Median Employee Salary | Hard |
| 570 | Managers with at Least 5 Direct Reports | Medium |
| 571 | Find Median Given Frequency of Numbers | Hard |
| 572 | Subtree of Another Tree | Easy |
| 573 | Squirrel Simulation | Medium |
| 574 | Winning Candidate | Medium |
| 575 | Distribute Candies | Easy |
| 576 | Out of Boundary Paths | Medium |
| 577 | Employee Bonus | Easy |
| 578 | Get Highest Answer Rate Question | Medium |
| 579 | Find Cumulative Salary of an Employee | Hard |
| 580 | Count Student Number in Departments | Medium |
| 581 | Shortest Unsorted Continuous Subarray | Easy |
| 582 | Kill Process | Medium |
| 583 | Delete Operation for Two Strings | Medium |
| 584 | Find Customer Referee | Easy |
| 585 | Investments in 2016 | Medium |
| 586 | Customer Placing the Largest Number of Orders | Easy |
| 587 | Erect the Fence | Hard |
| 588 | Design In-Memory File System | Hard |
| 591 | Tag Validator | Hard |
| 592 | Fraction Addition and Subtraction | Medium |
| 593 | Valid Square | Medium |
| 594 | Longest Harmonious Subsequence | Easy |
| 595 | Big Countries | Easy |
| 596 | Classes More Than 5 Students | Easy |
| 597 | Friend Requests I: Overall Acceptance Rate | Easy |
| 598 | Range Addition II | Easy |
| 599 | Minimum Index Sum of Two Lists | Easy |
| 600 | Non-negative Integers without Consecutive Ones | Hard |
| 601 | Human Traffic of Stadium | Hard |
| 602 | Friend Requests II: Who Has the Most Friends | Medium |
| 603 | Consecutive Available Seats | Easy |
| 604 | Design Compressed String Iterator | Easy |
| 605 | Can Place Flowers | Easy |
| 606 | Construct String from Binary Tree | Easy |
| 607 | Sales Person | Easy |
| 608 | Tree Node | Medium |
| 609 | Find Duplicate File in System | Medium |
| 610 | Triangle Judgement | Easy |
| 611 | Valid Triangle Number | Medium |
| 612 | Shortest Distance in a Plane | Medium |
| 613 | Shortest Distance in a Line | Easy |
| 614 | Second Degree Follower | Medium |
| 615 | Average Salary: Departments VS Company | Hard |
| 616 | Add Bold Tag in String | Medium |
| 617 | Merge Two Binary Trees | Easy |
| 618 | Students Report By Geography | Hard |
| 619 | Biggest Single Number | Easy |
| 620 | Not Boring Movies | Easy |
| 621 | Task Scheduler | Medium |
| 623 | Add One Row to Tree | Medium |
| 624 | Maximum Distance in Arrays | Easy |
| 625 | Minimum Factorization | Medium |
| 626 | Exchange Seats | Medium |
| 627 | Swap Salary | Easy |
| 628 | Maximum Product of Three Numbers | Easy |
| 629 | K Inverse Pairs Array | Hard |
| 630 | Course Schedule III | Hard |
| 631 | Design Excel Sum Formula | Hard |
| 632 | Smallest Range | Hard |
| 633 | Sum of Square Numbers | Easy |
| 634 | Find the Derangement of An Array | Medium |
| 635 | Design Log Storage System | 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 |
| 642 | Design Search Autocomplete System | Hard |
| 643 | Maximum Average Subarray I | Easy |
| 644 | Maximum Average Subarray II | Hard |
| 645 | Set Mismatch | Easy |
| 646 | Maximum Length of Pair Chain | Medium |
| 647 | Palindromic Substrings | Medium |
| 648 | Replace Words | Medium |
| 649 | Dota2 Senate | Medium |
| 650 | 2 Keys Keyboard | Medium |
| 651 | 4 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 |
| 656 | Coin Path | Hard |
| 657 | Judge Route Circle | Easy |
| 658 | Find K Closest Elements | Medium |
| 659 | Split Array into Consecutive Subsequences | Medium |
| 660 | Remove 9 | Hard |
| 661 | Image Smoother | Easy |
| 662 | Maximum Width of Binary Tree | Medium |
| 663 | Equal Tree Partition | Medium |
| 664 | Strange Printer | Hard |
| 665 | Non-decreasing Array | Easy |
| 666 | Path Sum IV | Medium |
| 667 | Beautiful Arrangement II | Medium |
| 668 | Kth Smallest Number in Multiplication Table | Hard |
| 669 | Trim a Binary Search Tree | Easy |
| 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 |
| 681 | Next Closest Time | Medium |
| 682 | Baseball Game | Easy |
| 683 | K Empty Slots | Hard |
| 684 | Redundant Connection | Medium |
| 685 | Redundant Connection II | Hard |
| 686 | Repeated String Match | Easy |
| 687 | Longest Univalue Path | Easy |
| 688 | Knight Probability in Chessboard | Medium |
| 689 | Maximum Sum of 3 Non-Overlapping Subarrays | Hard |
| 690 | Employee Importance | Easy |
| 691 | Stickers to Spell Word | Hard |
| 692 | Top K Frequent Words | Medium |
| 693 | Binary Number with Alternating Bits | Easy |
| 694 | Number of Distinct Islands | Medium |
| 695 | Max Area of Island | Easy |
| 696 | Count Binary Substrings | Easy |
| 697 | Degree of an Array | Easy |
| 698 | Partition to K Equal Sum Subsets | Medium |
| 699 | Falling Squares | Hard |
| 711 | Number of Distinct Islands II | 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 |
| 716 | Max Stack | 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 | Easy |
| 721 | Accounts Merge | Medium |
| 722 | Remove Comments | Medium |
| 723 | Candy Crush | Medium |
| 724 | Find Pivot Index | Easy |
| 725 | Split Linked List in Parts | Medium |
| 726 | Number of Atoms | Hard |
| 727 | Minimum Window Subsequence | 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 |
| 734 | Sentence Similarity | Easy |
| 735 | Asteroid Collision | Medium |
| 736 | Parse Lisp Expression | Hard |
| 737 | Sentence Similarity II | Medium |
| 738 | Monotone Increasing Digits | Medium |
| 739 | Daily Temperatures | Medium |
| 740 | Delete and Earn | Medium |
| 741 | Cherry Pickup | Hard |
| 742 | Closest Leaf in a Binary TreeNew | Medium |
| 743 | Network Delay TimeNew | Medium |
| 744 | Find Smallest Letter Greater Than TargetNew | Easy |
| 745 | Prefix and Suffix SearchNew | Hard |
