leetcode刷题记录

• 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 | dfs
• 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 | Stack
• 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 | LinkedList
• 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 | TreeMap
• 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 | Recursion
• 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
• 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   | 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
• 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
• 470 Implement Rand10() Using Rand7() | 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
• 478 Generate Random Point in a Circle | Medium
• 479 Largest Palindrome Product| Easy
• 480 Sliding Window Median| Hard
• 481 Magical String| Medium
• 482 License Key Formatting| Medium
• 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
• 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
• 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
• 559 Maximum Depth of N-ary Tree | 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
• 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
• 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
• 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 | Greedy
• 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
• 641 Design Circular Deque.md | 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
• 703 Kth Largest Element in a Stream | Easy
• 704 Binary Search | Easy
• 705 Design HashSet | Easy
• 706. Design HashMap | Easy
• 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 | Recursion
• 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 Tree|Medium
• 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|Medium
• 749 Contain Virus|Hard
• 750 Number Of Corner Rectangles|Medium
• 751 IP to CIDR|Easy
• 752 Open the Lock|Medium
• 753 Cracking the Safe|Hard
• 754 Reach a Number | Easy
• 755 Pour Water|Medium
• 756 Pyramid Transition Matrix |Medium
• 757 Set Intersection Size At Least Two|Hard
• 758 Bold Words in String|Easy
• 759 Employee Free Time|Hard
• 760 Find Anagram Mappings|Easy
• 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
• 771 Jewels and Stones|Easy
• 772 Basic Calculator III|Hard
• 773 Sliding Puzzle|Hard
• 774 Minimize Max Distance to Gas Station|Hard
• 775 Global and Local Inversions|Medium
• 776 Split BST|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|Easy
• 785 Is Graph Bipartite?|Medium
• 786 K-th Smallest Prime Fraction | Hard
• 787 Cheapest Flights Within K Stops|Medium
• 788 Rotated Digits    New Easy
• 789 Escape The Ghosts    New Medium
• 790 Domino and Tromino Tiling | Medium | dp
• 791 Custom Sort String  |  Medium
• 792 Number of Matching Subsequences | Medium
• 793 Preimage Size of Factorial Zeroes Function | Hard
• 795 Number of Subarrays with Bounded Maximum | Medium
• 796 Rotate String|Easy
• 797 All Paths From Source to Target | Medium
• 802 Find Eventual Safe States | Medium
• 804 Unique Morse Code Words | Easy
• 805 Split Array With Same Average | Hard
• 806 Number of Lines To Write String | Easy
• 807 Max Increase to Keep City Skyline | Medium
• 808 Soup Servings | Medium
• 812 Largest Triangle Area | Easy
• 816 Ambiguous Coordinates | Medium
• 817 Linked List Components | Medium | HashSet
• 819 Most Common Word | Easy
• 820 Short Encoding of Words | Medium
• 821 Shortest Distance to a Character | Easy
• 824 Goat Latin | Easy
• 826 Most Profit Assigning Work|Medium
• 830 Positions of Large Groups | Easy
• 832 Flipping an Image | Easy
• 835 Image Overlap | Medium
• 836 Rectangle Overlap | Easy
• 837 New 21 Game | Medium
• 844 Backspace String Compare| Easy
• 845 Longest Mountain in Array | Medium
• 846 Hand of Straights | Medium
• 848 Shifting Letters | Medium
• 849 Maximize Distance to Closest Person | Easy
• 851 Loud and Rich | Medium
• 852 Peak Index in a Mountain Array|Easy
• 853 Car Fleet | Medium
• 856 Score of Parentheses | Medium
• 858 Mirror Reflection | Medium
• 859 Buddy Strings | Easy
• 860 Lemonade Change | Medium
• 861 Score After Flipping Matrix | Medium
• 863 All Nodes Distance K in Binary Tree | Medium
• 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
• 872 Leaf-Similar Trees | Easy
• 873 Length of Longest Fibonacci Subsequence | Medium
• 875 Koko Eating Bananas | Medium
• 876 Middle of the Linked List | Easy
• 877 Stone Game | Medium
• 878 Nth Magical Number | Hard
• 881 Boats to Save People | Medium
• 883 Projection Area of 3D Shapes | Easy
• 884 Uncommon Words from Two Sentences | Easy
• 885 Spiral Matrix III | Medium
• 896 Possible Bipartition | Medium
• 888 Fair Candy Swap | Easy
• 890 Find and Replace Pattern | Medium
• 892 Surface Area of 3D Shapes | Easy
• 893 Groups of Special-Equivalent Strings | Easy
• 894 All Possible Full Binary Trees | Medium
• 896 Monotonic Array | Easy
• 897 Increasing Order Search Tree | Easy
• 899 Orderly Queue | Hard
• 904 Fruit Into Baskets | Medium
• 905 Sort Array By Parity | Easy
• 908 Smallest Range I | Easy
• 919 Complete Binary Tree Inserter | Tree
• 910 Smallest Range II | Medium
• 911 Online Election | Medium
• 914 X of a Kind in a Deck of Cards | Easy
• 915 Partition Array into Disjoint Intervals | Medium
• 916 Word Subsets | Medium
• 917 Reverse Only Letters | Easy
• 918 Maximum Sum Circular Subarray | Medium
• 921 Minimum Add to Make Parentheses Valid | Medium
• 922 Sort Array By Parity II | Easy
• 923 3Sum With Multiplicity | Medium
• 925 Long Pressed Name | Easy
• 926 Flip String to Monotone Increasing | Medium
• 927 Three Equal Parts | Hard |
• 930 Binary Subarrays With Sum | Medium
• 931 Minimum Falling Path Sum | Medium | Dp
• 933 Number of Recent Calls | Easy
• 935 Knight Dialer | Medium
• 938 Range Sum of BST | Medium
• 941. Valid Mountain Array | Easy
• 942 DI String Match | Easy
• 944 Delete Columns to Make Sorted | Medium
• 946 Validate Stack Sequences | Medium
• 947 Most Stones Removed with Same Row or Column | Medium
• 949 Largest Time for Given Digits | Easy
• 950 Reveal Cards In Increasing Order | Medium
• 951 Flip Equivalent Binary Trees | Medium
• 953 Verifying an Alien Dictionary | Easy
• 954 Array of Doubled Pairs | Medium
• 955 Delete Columns to Make Sorted II | Medium
• 957 Prison Cells After N Days | Medium
• 960 Delete Columns to Make Sorted III | Hard
• 961 N-Repeated Element in Size 2N Array | Easy
• 965 Univalued Binary Tree | Easy
• 969 Pancake Sorting |Medium
• 970 Powerful Integers | Easy
• 973 K Closest Points to Origin | Easy
• 975 Odd Even Jump | Hard
• 976 Largest Perimeter Triangle | Easy
• 977 Squares of a Sorted Array | Easy
• 979 Distribute Coins in Binary Tree | Medium
• 983 Minimum Cost For Tickets | Medium
• 982 Triples with Bitwise AND Equal To Zero | Hard
• 984 String Without AAA or BBB | Easy
• 985 Sum of Even Numbers After Queries | Easy
• 986 Interval List Intersections | Medium
• 988 Smallest String Starting From Leaf | Medium
• 987 Vertical Order Traversal of a Binary Tree | Medium
• 993 Cousins in Binary Tree | Easy
• 994 Rotting Oranges | Easy | BFS
• 995 Minimum Number of K Consecutive Bit Flips | Medium
• 997 Find the Town Judge | Easy
• 998 Maximum Binary Tree II | Medium
• 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
• 1008 Construct Binary Search Tree from Preorder Traversal | Medium
• 1010 Pairs of Songs With Total Durations Divisible by 60 | Easy
• 1016 Binary String With Substrings Representing 1 To N | Medium
• 1017 Convert to Base -2 | Medium
• 1018 Binary Prefix Divisible By 5 | Easy
• 1021 Remove Outermost Parentheses | Easy | Stack
• 1022 Sum of Root To Leaf Binary Numbers | Easy
• 1025 Divisor Game | Easy
• 1029 Two City Scheduling | Easy
• 1031 Maximum Sum of Two Non-Overlapping Subarrays | Medium
• 1035 Uncrossed Lines | Medium
• 1041 Robot Bounded In Circle | Easy
• 1043 Partition Array for Maximum Sum | Medium
• 1046 Last Stone Weight | Easy | PriorityQueue
• 1047 Remove All Adjacent Duplicates In String | Easy | Stack
• 1048. Longest String Chain | Medium | dp
• 1051 Height Checker | Easy
• 1052 Grumpy Bookstore Owner | Medium
• 1053 Previous Permutation With One Swap | Medium
• 1071 Greatest Common Divisor of Strings | Easy
• 1081 Smallest Subsequence of Distinct Characters | Medium
• 1089 Duplicate Zeros | Easy
• 1090 Largest Values From Labels | Medium | greedy
• 1091 Shortest Path in Binary Matrix | Medium | BFS
• 1092 Shortest Common Supersequence | Hard | Dp
• 1103 Distribute Candies to People | Easy
• 1104 Path In Zigzag Labelled Binary Tree
• 1108 Defanging an IP Address | Easy
• 1110 Delete Nodes And Return Forest | Medium | Tree
• 1111 Maximum Nesting Depth of Two Valid Parentheses Strings | Medium
• 1114 Print in Order | Easy| MultiThread
• 1128 Number of Equivalent Domino Pairs | Easy
• 1154 Day of the Year | Easy
• 1161 Maximum Level Sum of a Binary Tree | Medium | Tree
• 5083 Occurrences After Bigram | Easy
• 5084 Insufficient Nodes in Root to Leaf Paths | Medium | Tree
• 5087 Letter Tile Possibilities | Medium