list of all Problems from leetcode.
1 Easy Two Sum 2 Medium Add Two Numbers 3 Medium Longest Substring Without Repeating Characters 4 Hard Median of Two Sorted Arrays 5 Medium Longest Palindromic Substring 6 Medium ZigZag Conversion 7 Easy Reverse Integer 8 Medium String to Integer (atoi) 9 Easy Palindrome Number 10 Hard Regular Expression Matching 11 Medium Container With Most Water 12 Medium Integer to Roman 13 Easy Roman to Integer 14 Easy Longest Common Prefix 15 Medium 3Sum 16 Medium 3Sum Closest 17 Medium Letter Combinations of a Phone Number 18 Medium 4Sum 19 Medium Remove Nth Node From End of List 20 Easy Valid Parentheses 21 Easy Merge Two Sorted Lists 22 Medium Generate Parentheses 23 Hard Merge k Sorted Lists 24 Medium Swap Nodes in Pairs 25 Hard Reverse Nodes in k-Group 26 Easy Remove Duplicates from Sorted Array 27 Easy Remove Element 28 Easy Implement strStr() 29 Medium Divide Two Integers 30 Hard Substring with Concatenation of All Words 31 Medium Next Permutation 32 Hard Longest Valid Parentheses 33 Medium Search in Rotated Sorted Array 34 Medium Find First and Last Position of Element in Sorted Array 35 Easy Search Insert Position 36 Medium Valid Sudoku 37 Hard Sudoku Solver 38 Easy Count and Say 39 Medium Combination Sum 40 Medium Combination Sum II 41 Hard First Missing Positive 42 Hard Trapping Rain Water 43 Medium Multiply Strings 44 Hard Wildcard Matching 45 Hard Jump Game II 46 Medium Permutations 47 Medium Permutations II 48 Medium Rotate Image 49 Medium Group Anagrams 50 Medium Pow(x, n) 51 Hard N-Queens 52 Hard N-Queens II 53 Easy Maximum Subarray 54 Medium Spiral Matrix 55 Medium Jump Game 56 Medium Merge Intervals 57 Hard Insert Interval 58 Easy Length of Last Word 59 Medium Spiral Matrix II 60 Medium Permutation Sequence 61 Medium Rotate List 62 Medium Unique Paths 63 Medium Unique Paths II 64 Medium Minimum Path Sum 65 Hard Valid Number 66 Easy Plus One 67 Easy Add Binary 68 Hard Text Justification 69 Easy Sqrt(x) 70 Easy Climbing Stairs 71 Medium Simplify Path 72 Hard Edit Distance 73 Medium Set Matrix Zeroes 74 Medium Search a 2D Matrix 75 Medium Sort Colors 76 Hard Minimum Window Substring 77 Medium Combinations 78 Medium Subsets 79 Medium Word Search 80 Medium Remove Duplicates from Sorted Array II 81 Medium Search in Rotated Sorted Array II 82 Medium Remove Duplicates from Sorted List II 83 Easy Remove Duplicates from Sorted List 84 Hard Largest Rectangle in Histogram 85 Hard Maximal Rectangle 86 Medium Partition List 87 Hard Scramble String 88 Easy Merge Sorted Array 89 Medium Gray Code 90 Medium Subsets II 91 Medium Decode Ways 92 Medium Reverse Linked List II 93 Medium Restore IP Addresses 94 Medium Binary Tree Inorder Traversal 95 Medium Unique Binary Search Trees II 96 Medium Unique Binary Search Trees 97 Hard Interleaving String 98 Medium Validate Binary Search Tree 99 Hard Recover Binary Search Tree 100 Easy Same Tree 101 Easy Symmetric Tree 102 Medium Binary Tree Level Order Traversal 103 Medium Binary Tree Zigzag Level Order Traversal 104 Easy Maximum Depth of Binary Tree 105 Medium Construct Binary Tree from Preorder and Inorder Traversal 106 Medium Construct Binary Tree from Inorder and Postorder Traversal 107 Easy Binary Tree Level Order Traversal II 108 Easy Convert Sorted Array to Binary Search Tree 109 Medium Convert Sorted List to Binary Search Tree 110 Easy Balanced Binary Tree 111 Easy Minimum Depth of Binary Tree 112 Easy Path Sum 113 Medium Path Sum II 114 Medium Flatten Binary Tree to Linked List 115 Hard Distinct Subsequences 116 Medium Populating Next Right Pointers in Each Node 117 Medium Populating Next Right Pointers in Each Node II 118 Easy Pascal’s Triangle 119 Easy Pascal’s Triangle II 120 Medium Triangle 121 Easy Best Time to Buy and Sell Stock 122 Easy Best Time to Buy and Sell Stock II 123 Hard Best Time to Buy and Sell Stock III 124 Hard Binary Tree Maximum Path Sum 125 Easy Valid Palindrome 126 Hard Word Ladder II 127 Medium Word Ladder 128 Hard Longest Consecutive Sequence 129 Medium Sum Root to Leaf Numbers 130 Medium Surrounded Regions 131 Medium Palindrome Partitioning 132 Hard Palindrome Partitioning II 133 Medium Clone Graph 134 Medium Gas Station 135 Hard Candy 136 Easy Single Number 137 Medium Single Number II 138 Medium Copy List with Random Pointer 139 Medium Word Break 140 Hard Word Break II 141 Easy Linked List Cycle 142 Medium Linked List Cycle II 143 Medium Reorder List 144 Medium Binary Tree Preorder Traversal 145 Hard Binary Tree Postorder Traversal 146 Hard LRU Cache 147 Medium Insertion Sort List 148 Medium Sort List 149 Hard Max Points on a Line 150 Medium Evaluate Reverse Polish Notation 151 Medium Reverse Words in a String 152 Medium Maximum Product Subarray 153 Medium Find Minimum in Rotated Sorted Array 154 Hard Find Minimum in Rotated Sorted Array II 155 Easy Min Stack 156 Medium Binary Tree Upside Down 157 Easy Read N Characters Given Read4 158 Hard Read N Characters Given Read4 II - Call multiple times 159 Hard Longest Substring with At Most Two Distinct Characters 160 Easy Intersection of Two Linked Lists 161 Medium One Edit Distance 162 Medium Find Peak Element 163 Medium Missing Ranges 164 Hard Maximum Gap 165 Medium Compare Version Numbers 166 Medium Fraction to Recurring Decimal 167 Easy Two Sum II - Input array is sorted 168 Easy Excel Sheet Column Title 169 Easy Majority Element 170 Easy Two Sum III - Data structure design 171 Easy Excel Sheet Column Number 172 Easy Factorial Trailing Zeroes 173 Medium Binary Search Tree Iterator 174 Hard Dungeon Game 175 Easy Combine Two Tables 176 Easy Second Highest Salary 177 Medium Nth Highest Salary 178 Medium Rank Scores 179 Medium Largest Number 180 Medium Consecutive Numbers 181 Easy Employees Earning More Than Their Managers 182 Easy Duplicate Emails 183 Easy Customers Who Never Order 184 Medium Department Highest Salary 185 Hard Department Top Three Salaries 186 Medium Reverse Words in a String II 187 Medium Repeated DNA Sequences 188 Hard Best Time to Buy and Sell Stock IV 189 Easy Rotate Array 190 Easy Reverse Bits 191 Easy Number of 1 Bits 192 Medium Word Frequency 193 Easy Valid Phone Numbers 194 Medium Transpose File 195 Easy Tenth Line 196 Easy Delete Duplicate Emails 197 Easy Rising Temperature 198 Easy House Robber 199 Medium Binary Tree Right Side View 200 Medium Number of Islands 201 Medium Bitwise AND of Numbers Range 202 Easy Happy Number 203 Easy Remove Linked List Elements 204 Easy Count Primes 205 Easy Isomorphic Strings 206 Easy Reverse Linked List 207 Medium Course Schedule 208 Medium Implement Trie (Prefix Tree) 209 Medium Minimum Size Subarray Sum 210 Medium Course Schedule II 211 Medium Add and Search Word - Data structure design 212 Hard Word Search II 213 Medium House Robber II 214 Hard Shortest Palindrome 215 Medium Kth Largest Element in an Array 216 Medium Combination Sum III 217 Easy Contains Duplicate 218 Hard The Skyline Problem 219 Easy Contains Duplicate II 220 Medium Contains Duplicate III 221 Medium Maximal Square 222 Medium Count Complete Tree Nodes 223 Medium Rectangle Area 224 Hard Basic Calculator 225 Easy Implement Stack using Queues 226 Easy Invert Binary Tree 227 Medium Basic Calculator II 228 Medium Summary Ranges 229 Medium Majority Element II 230 Medium Kth Smallest Element in a BST 231 Easy Power of Two 232 Easy Implement Queue using Stacks 233 Hard Number of Digit One 234 Easy Palindrome Linked List 235 Easy Lowest Common Ancestor of a Binary Search Tree 236 Medium Lowest Common Ancestor of a Binary Tree 237 Easy Delete Node in a Linked List 238 Medium Product of Array Except Self 239 Hard Sliding Window Maximum 240 Medium Search a 2D Matrix II 241 Medium Different Ways to Add Parentheses 242 Easy Valid Anagram 243 Easy Shortest Word Distance 244 Medium Shortest Word Distance II 245 Medium Shortest Word Distance III 246 Easy Strobogrammatic Number 247 Medium Strobogrammatic Number II 248 Hard Strobogrammatic Number III 249 Medium Group Shifted Strings 250 Medium Count Univalue Subtrees 251 Medium Flatten 2D Vector 252 Easy Meeting Rooms 253 Medium Meeting Rooms II 254 Medium Factor Combinations 255 Medium Verify Preorder Sequence in Binary Search Tree 256 Easy Paint House 257 Easy Binary Tree Paths 258 Easy Add Digits 259 Medium 3Sum Smaller 260 Medium Single Number III 261 Medium Graph Valid Tree 262 Hard Trips and Users 263 Easy Ugly Number 264 Medium Ugly Number II 265 Hard Paint House II 266 Easy Palindrome Permutation 267 Medium Palindrome Permutation II 268 Easy Missing Number 269 Hard Alien Dictionary 270 Easy Closest Binary Search Tree Value 271 Medium Encode and Decode Strings 272 Hard Closest Binary Search Tree Value II 273 Hard Integer to English Words 274 Medium H-Index 275 Medium H-Index II 276 Easy Paint Fence 277 Medium Find the Celebrity 278 Easy First Bad Version 279 Medium Perfect Squares 280 Medium Wiggle Sort 281 Medium Zigzag Iterator 282 Hard Expression Add Operators 283 Easy Move Zeroes 284 Medium Peeking Iterator 285 Medium Inorder Successor in BST 286 Medium Walls and Gates 287 Medium Find the Duplicate Number 288 Medium Unique Word Abbreviation 289 Medium Game of Life 290 Easy Word Pattern 291 Hard Word Pattern II 292 Easy Nim Game 293 Easy Flip Game 294 Medium Flip Game II 295 Hard Find Median from Data Stream 296 Hard Best Meeting Point 297 Hard Serialize and Deserialize Binary Tree 298 Medium Binary Tree Longest Consecutive Sequence 299 Medium Bulls and Cows 300 Medium Longest Increasing Subsequence 301 Hard Remove Invalid Parentheses 302 Hard Smallest Rectangle Enclosing Black Pixels 303 Easy Range Sum Query - Immutable 304 Medium Range Sum Query 2D - Immutable 305 Hard Number of Islands II 306 Medium Additive Number 307 Medium Range Sum Query - Mutable 308 Hard Range Sum Query 2D - Mutable 309 Medium Best Time to Buy and Sell Stock with Cooldown 310 Medium Minimum Height Trees 311 Medium Sparse Matrix Multiplication 312 Hard Burst Balloons 313 Medium Super Ugly Number 314 Medium Binary Tree Vertical Order Traversal 315 Hard Count of Smaller Numbers After Self 316 Hard Remove Duplicate Letters 317 Hard Shortest Distance from All Buildings 318 Medium Maximum Product of Word Lengths 319 Medium Bulb Switcher 320 Medium Generalized Abbreviation 321 Hard Create Maximum Number 322 Medium Coin Change 323 Medium Number of Connected Components in an Undirected Graph 324 Medium Wiggle Sort II 325 Medium Maximum Size Subarray Sum Equals k 326 Easy Power of Three 327 Hard Count of Range Sum 328 Medium Odd Even Linked List 329 Hard Longest Increasing Path in a Matrix 330 Hard Patching Array 331 Medium Verify Preorder Serialization of a Binary Tree 332 Medium Reconstruct Itinerary 333 Medium Largest BST Subtree 334 Medium Increasing Triplet Subsequence 335 Hard Self Crossing 336 Hard Palindrome Pairs 337 Medium House Robber III 338 Medium Counting Bits 339 Easy Nested List Weight Sum 340 Hard Longest Substring with At Most K Distinct Characters 341 Medium Flatten Nested List Iterator 342 Easy Power of Four 343 Medium Integer Break 344 Easy Reverse String 345 Easy Reverse Vowels of a String 346 Easy Moving Average from Data Stream 347 Medium Top K Frequent Elements 348 Medium Design Tic-Tac-Toe 349 Easy Intersection of Two Arrays 350 Easy Intersection of Two Arrays II 351 Medium Android Unlock Patterns 352 Hard Data Stream as Disjoint Intervals 353 Medium Design Snake Game 354 Hard Russian Doll Envelopes 355 Medium Design Twitter 356 Medium Line Reflection 357 Medium Count Numbers with Unique Digits 358 Hard Rearrange String k Distance Apart 359 Easy Logger Rate Limiter 360 Medium Sort Transformed Array 361 Medium Bomb Enemy 362 Medium Design Hit Counter 363 Hard Max Sum of Rectangle No Larger Than K 364 Medium Nested List Weight Sum II 365 Medium Water and Jug Problem 366 Medium Find Leaves of Binary Tree 367 Easy Valid Perfect Square 368 Medium Largest Divisible Subset 369 Medium Plus One Linked List 370 Medium Range Addition 371 Easy Sum of Two Integers 372 Medium Super Pow 373 Medium Find K Pairs with Smallest Sums 374 Easy Guess Number Higher or Lower 375 Medium Guess Number Higher or Lower II 376 Medium Wiggle Subsequence 377 Medium Combination Sum IV 378 Medium Kth Smallest Element in a Sorted Matrix 379 Medium Design Phone Directory 380 Medium Insert Delete GetRandom O(1) 381 Hard Insert Delete GetRandom O(1) - Duplicates allowed 382 Medium Linked List Random Node 383 Easy Ransom Note 384 Medium Shuffle an Array 385 Medium Mini Parser 386 Medium Lexicographical Numbers 387 Easy First Unique Character in a String 388 Medium Longest Absolute File Path 389 Easy Find the Difference 390 Medium Elimination Game 391 Hard Perfect Rectangle 392 Medium Is Subsequence 393 Medium UTF-8 Validation 394 Medium Decode String 395 Medium Longest Substring with At Least K Repeating Characters 396 Medium Rotate Function 397 Medium Integer Replacement 398 Medium Random Pick Index 399 Medium Evaluate Division 400 Easy Nth Digit 401 Easy Binary Watch 402 Medium Remove K Digits 403 Hard Frog Jump 404 Easy Sum of Left Leaves 405 Easy Convert a Number to Hexadecimal 406 Medium Queue Reconstruction by Height 407 Hard Trapping Rain Water II 408 Easy Valid Word Abbreviation 409 Easy Longest Palindrome 410 Hard Split Array Largest Sum 411 Hard Minimum Unique Word Abbreviation 412 Easy Fizz Buzz 413 Medium Arithmetic Slices 414 Easy Third Maximum Number 415 Easy Add Strings 416 Medium Partition Equal Subset Sum 417 Medium Pacific Atlantic Water Flow 418 Medium Sentence Screen Fitting 419 Medium Battleships in a Board 420 Hard Strong Password Checker 421 Medium Maximum XOR of Two Numbers in an Array 422 Easy Valid Word Square 423 Medium Reconstruct Original Digits from English 424 Medium Longest Repeating Character Replacement 425 Hard Word Squares 426 Medium Convert Binary Search Tree to Sorted Doubly Linked List 427 Easy Construct Quad Tree 428 Hard Serialize and Deserialize N-ary Tree 429 Easy N-ary Tree Level Order Traversal 430 Medium Flatten a Multilevel Doubly Linked List 431 Hard Encode N-ary Tree to Binary Tree 432 Hard All O`one Data Structure 433 Medium Minimum Genetic Mutation 434 Easy Number of Segments in a String 435 Medium Non-overlapping Intervals 436 Medium Find Right Interval 437 Easy Path Sum III 438 Easy Find All Anagrams in a String 439 Medium Ternary Expression Parser 440 Hard K-th Smallest in Lexicographical Order 441 Easy Arranging Coins 442 Medium Find All Duplicates in an Array 443 Easy String Compression 444 Medium Sequence Reconstruction 445 Medium Add Two Numbers II 446 Hard Arithmetic Slices II - Subsequence 447 Easy Number of Boomerangs 448 Easy Find All Numbers Disappeared in an Array 449 Medium Serialize and Deserialize BST 450 Medium Delete Node in a BST 451 Medium Sort Characters By Frequency 452 Medium Minimum Number of Arrows to Burst Balloons 453 Easy Minimum Moves to Equal Array Elements 454 Medium 4Sum II 455 Easy Assign Cookies 456 Medium 132 Pattern 457 Medium Circular Array Loop 458 Hard Poor Pigs 459 Easy Repeated Substring Pattern 460 Hard LFU Cache 461 Easy Hamming Distance 462 Medium Minimum Moves to Equal Array Elements II 463 Easy Island Perimeter 464 Medium Can I Win 465 Hard Optimal Account Balancing 466 Hard Count The Repetitions 467 Medium Unique Substrings in Wraparound String 468 Medium Validate IP Address 469 Medium Convex Polygon 470 Medium Implement Rand10() Using Rand7() 471 Hard Encode String with Shortest Length 472 Hard Concatenated Words 473 Medium Matchsticks to Square 474 Medium Ones and Zeroes 475 Easy Heaters 476 Easy Number Complement 477 Medium Total Hamming Distance 478 Medium Generate Random Point in a Circle 479 Hard Largest Palindrome Product 480 Hard Sliding Window Median 481 Medium Magical String 482 Easy License Key Formatting 483 Hard Smallest Good Base 484 Medium Find Permutation 485 Easy Max Consecutive Ones 486 Medium Predict the Winner 487 Medium Max Consecutive Ones II 488 Hard Zuma Game 489 Hard Robot Room Cleaner 490 Medium The Maze 491 Medium Increasing Subsequences 492 Easy Construct the Rectangle 493 Hard Reverse Pairs 494 Medium Target Sum 495 Medium Teemo Attacking 496 Easy Next Greater Element I 497 Medium Random Point in Non-overlapping Rectangles 498 Medium Diagonal Traverse 499 Hard The Maze III 500 Easy Keyboard Row 501 Easy Find Mode in Binary Search Tree 502 Hard IPO 503 Medium Next Greater Element II 504 Easy Base 7 505 Medium The Maze II 506 Easy Relative Ranks 507 Easy Perfect Number 508 Medium Most Frequent Subtree Sum 509 Easy Fibonacci Number 510 Medium Inorder Successor in BST II 513 Medium Find Bottom Left Tree Value 514 Hard Freedom Trail 515 Medium Find Largest Value in Each Tree Row 516 Medium Longest Palindromic Subsequence 517 Hard Super Washing Machines 518 Medium Coin Change 2 519 Medium Random Flip Matrix 520 Easy Detect Capital 521 Easy Longest Uncommon Subsequence I 522 Medium Longest Uncommon Subsequence II 523 Medium Continuous Subarray Sum 524 Medium Longest Word in Dictionary through Deleting 525 Medium Contiguous Array 526 Medium Beautiful Arrangement 527 Hard Word Abbreviation 528 Medium Random Pick with Weight 529 Medium Minesweeper 530 Easy Minimum Absolute Difference in BST 531 Medium Lonely Pixel I 532 Easy K-diff Pairs in an Array 533 Medium Lonely Pixel II 535 Medium Encode and Decode TinyURL 536 Medium Construct Binary Tree from String 537 Medium Complex Number Multiplication 538 Easy Convert BST to Greater Tree 539 Medium Minimum Time Difference 540 Medium Single Element in a Sorted Array 541 Easy Reverse String II 542 Medium 01 Matrix 543 Easy Diameter of Binary Tree 544 Medium Output Contest Matches 545 Medium Boundary of Binary Tree 546 Hard Remove Boxes 547 Medium Friend Circles 548 Medium Split Array with Equal Sum 549 Medium Binary Tree Longest Consecutive Sequence II 551 Easy Student Attendance Record I 552 Hard Student Attendance Record II 553 Medium Optimal Division 554 Medium Brick Wall 555 Medium Split Concatenated Strings 556 Medium Next Greater Element III 557 Easy Reverse Words in a String III 558 Easy Quad Tree Intersection 559 Easy Maximum Depth of N-ary Tree 560 Medium Subarray Sum Equals K 561 Easy Array Partition I 562 Medium Longest Line of Consecutive One in Matrix 563 Easy Binary Tree Tilt 564 Hard Find the Closest Palindrome 565 Medium Array Nesting 566 Easy Reshape the Matrix 567 Medium Permutation in String 568 Hard Maximum Vacation Days 569 Hard Median Employee Salary 570 Medium Managers with at Least 5 Direct Reports 571 Hard Find Median Given Frequency of Numbers 572 Easy Subtree of Another Tree 573 Medium Squirrel Simulation 574 Medium Winning Candidate 575 Easy Distribute Candies 576 Medium Out of Boundary Paths 577 Easy Employee Bonus 578 Medium Get Highest Answer Rate Question 579 Hard Find Cumulative Salary of an Employee 580 Medium Count Student Number in Departments 581 Easy Shortest Unsorted Continuous Subarray 582 Medium Kill Process 583 Medium Delete Operation for Two Strings 584 Easy Find Customer Referee 585 Medium Investments in 2016 586 Easy Customer Placing the Largest Number of Orders 587 Hard Erect the Fence 588 Hard Design In-Memory File System 589 Easy N-ary Tree Preorder Traversal 590 Easy N-ary Tree Postorder Traversal 591 Hard Tag Validator 592 Medium Fraction Addition and Subtraction 593 Medium Valid Square 594 Easy Longest Harmonious Subsequence 595 Easy Big Countries 596 Easy Classes More Than 5 Students 597 Easy Friend Requests I: Overall Acceptance Rate 598 Easy Range Addition II 599 Easy Minimum Index Sum of Two Lists 600 Hard Non-negative Integers without Consecutive Ones 601 Hard Human Traffic of Stadium 602 Medium Friend Requests II: Who Has the Most Friends 603 Easy Consecutive Available Seats 604 Easy Design Compressed String Iterator 605 Easy Can Place Flowers 606 Easy Construct String from Binary Tree 607 Easy Sales Person 608 Medium Tree Node 609 Medium Find Duplicate File in System 610 Easy Triangle Judgement 611 Medium Valid Triangle Number 612 Medium Shortest Distance in a Plane 613 Easy Shortest Distance in a Line 614 Medium Second Degree Follower 615 Hard Average Salary: Departments VS Company 616 Medium Add Bold Tag in String 617 Easy Merge Two Binary Trees 618 Hard Students Report By Geography 619 Easy Biggest Single Number 620 Easy Not Boring Movies 621 Medium Task Scheduler 622 Medium Design Circular Queue 623 Medium Add One Row to Tree 624 Easy Maximum Distance in Arrays 625 Medium Minimum Factorization 626 Medium Exchange Seats 627 Easy Swap Salary 628 Easy Maximum Product of Three Numbers 629 Hard K Inverse Pairs Array 630 Hard Course Schedule III 631 Hard Design Excel Sum Formula 632 Hard Smallest Range 633 Easy Sum of Square Numbers 634 Medium Find the Derangement of An Array 635 Medium Design Log Storage System 636 Medium Exclusive Time of Functions 637 Easy Average of Levels in Binary Tree 638 Medium Shopping Offers 639 Hard Decode Ways II 640 Medium Solve the Equation 641 Medium Design Circular Deque 642 Hard Design Search Autocomplete System 643 Easy Maximum Average Subarray I 644 Hard Maximum Average Subarray II 645 Easy Set Mismatch 646 Medium Maximum Length of Pair Chain 647 Medium Palindromic Substrings 648 Medium Replace Words 649 Medium Dota2 Senate 650 Medium 2 Keys Keyboard 651 Medium 4 Keys Keyboard 652 Medium Find Duplicate Subtrees 653 Easy Two Sum IV - Input is a BST 654 Medium Maximum Binary Tree 655 Medium Print Binary Tree 656 Hard Coin Path 657 Easy Robot Return to Origin 658 Medium Find K Closest Elements 659 Medium Split Array into Consecutive Subsequences 660 Hard Remove 9 661 Easy Image Smoother 662 Medium Maximum Width of Binary Tree 663 Medium Equal Tree Partition 664 Hard Strange Printer 665 Easy Non-decreasing Array 666 Medium Path Sum IV 667 Medium Beautiful Arrangement II 668 Hard Kth Smallest Number in Multiplication Table 669 Easy Trim a Binary Search Tree 670 Medium Maximum Swap 671 Easy Second Minimum Node In a Binary Tree 672 Medium Bulb Switcher II 673 Medium Number of Longest Increasing Subsequence 674 Easy Longest Continuous Increasing Subsequence 675 Hard Cut Off Trees for Golf Event 676 Medium Implement Magic Dictionary 677 Medium Map Sum Pairs 678 Medium Valid Parenthesis String 679 Hard 24 Game 680 Easy Valid Palindrome II 681 Medium Next Closest Time 682 Easy Baseball Game 683 Hard K Empty Slots 684 Medium Redundant Connection 685 Hard Redundant Connection II 686 Easy Repeated String Match 687 Easy Longest Univalue Path 688 Medium Knight Probability in Chessboard 689 Hard Maximum Sum of 3 Non-Overlapping Subarrays 690 Easy Employee Importance 691 Hard Stickers to Spell Word 692 Medium Top K Frequent Words 693 Easy Binary Number with Alternating Bits 694 Medium Number of Distinct Islands 695 Medium Max Area of Island 696 Easy Count Binary Substrings 697 Easy Degree of an Array 698 Medium Partition to K Equal Sum Subsets 699 Hard Falling Squares 700 Easy Search in a Binary Search Tree 701 Medium Insert into a Binary Search Tree 702 Medium Search in a Sorted Array of Unknown Size 703 Easy Kth Largest Element in a Stream 704 Easy Binary Search 705 Easy Design HashSet 706 Easy Design HashMap 707 Easy Design Linked List 708 Medium Insert into a Cyclic Sorted List 709 Easy To Lower Case 710 Hard Random Pick with Blacklist 711 Hard Number of Distinct Islands II 712 Medium Minimum ASCII Delete Sum for Two Strings 713 Medium Subarray Product Less Than K 714 Medium Best Time to Buy and Sell Stock with Transaction Fee 715 Hard Range Module 716 Easy Max Stack 717 Easy 1-bit and 2-bit Characters 718 Medium Maximum Length of Repeated Subarray 719 Hard Find K-th Smallest Pair Distance 720 Easy Longest Word in Dictionary 721 Medium Accounts Merge 722 Medium Remove Comments 723 Medium Candy Crush 724 Easy Find Pivot Index 725 Medium Split Linked List in Parts 726 Hard Number of Atoms 727 Hard Minimum Window Subsequence 728 Easy Self Dividing Numbers 729 Medium My Calendar I 730 Hard Count Different Palindromic Subsequences 731 Medium My Calendar II 732 Hard My Calendar III 733 Easy Flood Fill 734 Easy Sentence Similarity 735 Medium Asteroid Collision 736 Hard Parse Lisp Expression 737 Medium Sentence Similarity II 738 Medium Monotone Increasing Digits 739 Medium Daily Temperatures 740 Medium Delete and Earn 741 Hard Cherry Pickup 742 Medium Closest Leaf in a Binary Tree 743 Medium Network Delay Time 744 Easy Find Smallest Letter Greater Than Target 745 Hard Prefix and Suffix Search 746 Easy Min Cost Climbing Stairs 747 Easy Largest Number At Least Twice of Others 748 Easy Shortest Completing Word 749 Hard Contain Virus 750 Medium Number Of Corner Rectangles 751 Easy IP to CIDR 752 Medium Open the Lock 753 Hard Cracking the Safe 754 Easy Reach a Number 755 Medium Pour Water 756 Medium Pyramid Transition Matrix 757 Hard Set Intersection Size At Least Two 758 Easy Bold Words in String 759 Hard Employee Free Time 760 Easy Find Anagram Mappings 761 Hard Special Binary String 762 Easy Prime Number of Set Bits in Binary Representation 763 Medium Partition Labels 764 Medium Largest Plus Sign 765 Hard Couples Holding Hands 766 Easy Toeplitz Matrix 767 Medium Reorganize String 768 Hard Max Chunks To Make Sorted II 769 Medium Max Chunks To Make Sorted 770 Hard Basic Calculator IV 771 Easy Jewels and Stones 772 Hard Basic Calculator III 773 Hard Sliding Puzzle 774 Hard Minimize Max Distance to Gas Station 775 Medium Global and Local Inversions 776 Medium Split BST 777 Medium Swap Adjacent in LR String 778 Hard Swim in Rising Water 779 Medium K-th Symbol in Grammar 780 Hard Reaching Points 781 Medium Rabbits in Forest 782 Hard Transform to Chessboard 783 Easy Minimum Distance Between BST Nodes 784 Easy Letter Case Permutation 785 Medium Is Graph Bipartite? 786 Hard K-th Smallest Prime Fraction 787 Medium Cheapest Flights Within K Stops 788 Easy Rotated Digits 789 Medium Escape The Ghosts 790 Medium Domino and Tromino Tiling 791 Medium Custom Sort String 792 Medium Number of Matching Subsequences 793 Hard Preimage Size of Factorial Zeroes Function 794 Medium Valid Tic-Tac-Toe State 795 Medium Number of Subarrays with Bounded Maximum 796 Easy Rotate String 797 Medium All Paths From Source to Target 798 Hard Smallest Rotation with Highest Score 799 Medium Champagne Tower 800 Easy Similar RGB Color 801 Medium Minimum Swaps To Make Sequences Increasing 802 Medium Find Eventual Safe States 803 Hard Bricks Falling When Hit 804 Easy Unique Morse Code Words 805 Hard Split Array With Same Average 806 Easy Number of Lines To Write String 807 Medium Max Increase to Keep City Skyline 808 Medium Soup Servings 809 Medium Expressive Words 810 Hard Chalkboard XOR Game 811 Easy Subdomain Visit Count 812 Easy Largest Triangle Area 813 Medium Largest Sum of Averages 814 Medium Binary Tree Pruning 815 Hard Bus Routes 816 Medium Ambiguous Coordinates 817 Medium Linked List Components 818 Hard Race Car 819 Easy Most Common Word 820 Medium Short Encoding of Words 821 Easy Shortest Distance to a Character 822 Medium Card Flipping Game 823 Medium Binary Trees With Factors 824 Easy Goat Latin 825 Medium Friends Of Appropriate Ages 826 Medium Most Profit Assigning Work 827 Hard Making A Large Island 828 Hard Unique Letter String 829 Hard Consecutive Numbers Sum 830 Easy Positions of Large Groups 831 Medium Masking Personal Information 832 Easy Flipping an Image 833 Medium Find And Replace in String 834 Hard Sum of Distances in Tree 835 Medium Image Overlap 836 Easy Rectangle Overlap 837 Medium New 21 Game 838 Medium Push Dominoes 839 Hard Similar String Groups 840 Easy Magic Squares In Grid 841 Medium Keys and Rooms 842 Medium Split Array into Fibonacci Sequence 843 Hard Guess the Word 844 Easy Backspace String Compare 845 Medium Longest Mountain in Array 846 Medium Hand of Straights 847 Hard Shortest Path Visiting All Nodes 848 Medium Shifting Letters 849 Easy Maximize Distance to Closest Person 850 Hard Rectangle Area II 851 Medium Loud and Rich 852 Easy Peak Index in a Mountain Array 853 Medium Car Fleet 854 Hard K-Similar Strings 855 Medium Exam Room 856 Medium Score of Parentheses 857 Hard Minimum Cost to Hire K Workers 858 Medium Mirror Reflection 859 Easy Buddy Strings 860 Easy Lemonade Change 861 Medium Score After Flipping Matrix 862 Hard Shortest Subarray with Sum at Least K 863 Medium All Nodes Distance K in Binary Tree 864 Hard Shortest Path to Get All Keys 865 Medium Smallest Subtree with all the Deepest Nodes 866 Medium Prime Palindrome 867 Easy Transpose Matrix 868 Easy Binary Gap 869 Medium Reordered Power of 2 870 Medium Advantage Shuffle 871 Hard Minimum Number of Refueling Stops 872 Easy Leaf-Similar Trees 873 Medium Length of Longest Fibonacci Subsequence 874 Easy Walking Robot Simulation 875 Medium Koko Eating Bananas 876 Easy Middle of the Linked List 877 Medium Stone Game 878 Hard Nth Magical Number 879 Hard Profitable Schemes 880 Medium Decoded String at Index 881 Medium Boats to Save People 882 Hard Reachable Nodes In Subdivided Graph 883 Easy Projection Area of 3D Shapes 884 Easy Uncommon Words from Two Sentences 885 Medium Spiral Matrix III 886 Medium Possible Bipartition 887 Hard Super Egg Drop 888 Easy Fair Candy Swap 889 Medium Construct Binary Tree from Preorder and Postorder Traversal 890 Medium Find and Replace Pattern 891 Hard Sum of Subsequence Widths 892 Easy Surface Area of 3D Shapes 893 Easy Groups of Special-Equivalent Strings 894 Medium All Possible Full Binary Trees 895 Hard Maximum Frequency Stack 896 Easy Monotonic Array 897 Easy Increasing Order Search Tree 898 Medium Bitwise ORs of Subarrays 899 Hard Orderly Queue 900 Medium RLE Iterator 901 Medium Online Stock Span 902 Hard Numbers At Most N Given Digit Set 903 Hard Valid Permutations for DI Sequence 904 Medium Fruit Into Baskets 905 Easy Sort Array By Parity 906 Hard Super Palindromes 907 Medium Sum of Subarray Minimums 908 Easy Smallest Range I 909 Medium Snakes and Ladders 910 Medium Smallest Range II 911 Medium Online Election 912 Medium Sort an Array 913 Hard Cat and Mouse 914 Easy X of a Kind in a Deck of Cards 915 Medium Partition Array into Disjoint Intervals 916 Medium Word Subsets 917 Easy Reverse Only Letters 918 Medium Maximum Sum Circular Subarray 919 Medium Complete Binary Tree Inserter 920 Hard Number of Music Playlists 921 Medium Minimum Add to Make Parentheses Valid 922 Easy Sort Array By Parity II 923 Medium 3Sum With Multiplicity 924 Hard Minimize Malware Spread 925 Easy Long Pressed Name 926 Medium Flip String to Monotone Increasing 927 Hard Three Equal Parts 928 Hard Minimize Malware Spread II 929 Easy Unique Email Addresses 930 Medium Binary Subarrays With Sum 931 Medium Minimum Falling Path Sum 932 Medium Beautiful Array 933 Easy Number of Recent Calls 934 Medium Shortest Bridge 935 Medium Knight Dialer 936 Hard Stamping The Sequence 937 Easy Reorder Log Files 938 Medium Range Sum of BST 939 Medium Minimum Area Rectangle 940 Hard Distinct Subsequences II 941 Easy Valid Mountain Array 942 Easy DI String Match 943 Hard Find the Shortest Superstring 944 Easy Delete Columns to Make Sorted 945 Medium Minimum Increment to Make Array Unique 946 Medium Validate Stack Sequences 947 Medium Most Stones Removed with Same Row or Column 948 Medium Bag of Tokens 949 Easy Largest Time for Given Digits 950 Medium Reveal Cards In Increasing Order 951 Medium Flip Equivalent Binary Trees 952 Hard Largest Component Size by Common Factor 953 Easy Verifying an Alien Dictionary 954 Medium Array of Doubled Pairs 955 Medium Delete Columns to Make Sorted II 956 Hard Tallest Billboard 957 Medium Prison Cells After N Days 958 Medium Check Completeness of a Binary Tree 959 Medium Regions Cut By Slashes 960 Hard Delete Columns to Make Sorted III 961 Easy N-Repeated Element in Size 2N Array 962 Medium Maximum Width Ramp 963 Medium Minimum Area Rectangle II 964 Hard Least Operators to Express Number 965 Easy Univalued Binary Tree 966 Medium Vowel Spellchecker 967 Medium Numbers With Same Consecutive Differences 968 Hard Binary Tree Cameras 969 Medium Pancake Sorting 970 Easy Powerful Integers 971 Medium Flip Binary Tree To Match Preorder Traversal 972 Hard Equal Rational Numbers 973 Medium K Closest Points to Origin 974 Medium Subarray Sums Divisible by K 975 Hard Odd Even Jump 976 Easy Largest Perimeter Triangle 977 Easy Squares of a Sorted Array 978 Medium Longest Turbulent Subarray 979 Medium Distribute Coins in Binary Tree 980 Hard Unique Paths III 981 Medium Time Based Key-Value Store 982 Hard Triples with Bitwise AND Equal To Zero 983 Medium Minimum Cost For Tickets 984 Medium String Without AAA or BBB 985 Easy Sum of Even Numbers After Queries 986 Medium Interval List Intersections 987 Medium Vertical Order Traversal of a Binary Tree 988 Medium Smallest String Starting From Leaf 989 Easy Add to Array-Form of Integer 990 Medium Satisfiability of Equality Equations 991 Medium Broken Calculator 992 Hard Subarrays with K Different Integers 993 Easy Cousins in Binary Tree 994 Easy Rotting Oranges 995 Hard Minimum Number of K Consecutive Bit Flips 996 Hard Number of Squareful Arrays 997 Easy Find the Town Judge 998 Medium Maximum Binary Tree II 999 Easy Available Captures for Rook 1000 Hard Minimum Cost to Merge Stones 1001 Hard Grid Illumination 1002 Easy Find Common Characters 1003 Medium Check If Word Is Valid After Substitutions 1004 Medium Max Consecutive Ones III 1005 Easy Maximize Sum Of Array After K Negations 1006 Medium Clumsy Factorial 1007 Medium Minimum Domino Rotations For Equal Row 1008 Medium Construct Binary Search Tree from Preorder Traversal 1009 Easy Complement of Base 10 Integer 1010 Easy Pairs of Songs With Total Durations Divisible by 60 1011 Medium Capacity To Ship Packages Within D Days 1012 Hard Numbers With Repeated Digits 1013 Easy Partition Array Into Three Parts With Equal Sum 1014 Medium Best Sightseeing Pair 1015 Medium Smallest Integer Divisible by K 1016 Medium Binary String With Substrings Representing 1 To N 1017 Medium Convert to Base -2 1018 Easy Binary Prefix Divisible By 5 1019 Medium Next Greater Node In Linked List 1020 Medium Number of Enclaves 1021 Easy Remove Outermost Parentheses 1022 Easy Sum of Root To Leaf Binary Numbers 1023 Medium Camelcase Matching 1024 Medium Video Stitching 1025 Easy Divisor Game 1026 Medium Maximum Difference Between Node and Ancestor 1027 Medium Longest Arithmetic Sequence 1028 Hard Recover a Tree From Preorder Traversal 1029 Easy Two City Scheduling 1030 Easy Matrix Cells in Distance Order 1031 Medium Maximum Sum of Two Non-Overlapping Subarrays 1032 Hard Stream of Characters
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