LeetCode.swift

愚者千虑，必有一得。

As an idiot of algorithms, I make bold to resolve the problems on LeetCode, especially, in Swift. Most of the algorithms were not figured out by myself.

let 😎 = "Easy", 😐 = "Medium", 😨 = "Hard", ㊙️ = "require premium membership"

• [x] 1 😎 Two Sum .swift
• [x] 2 😐 Add Two Numbers .swift
• [x] 3 😐 Longest Substring Without Repeating Characters .swift
• [ ] 4 😨 Median of Two Sorted Arrays
• [x] 5 😐 Longest Palindromic Substring .swift
• [x] 6 😐 ZigZag Conversion .swift
• [x] 7 😎 Reverse Integer .swift
• [x] 8 😐 String to Integer (atoi) .swift
• [x] 9 😎 Palindrome Number .swift
• [ ] 10 😨 Regular Expression Matching
• [ ] 11 😐 Container With Most Water
• [x] 12 😐 Integer to Roman .swift
• [x] 13 😎 Roman to Integer .swift
• [x] 14 😎 Longest Common Prefix .swift
• [ ] 15 😐 3Sum
• [ ] 16 😐 3Sum Closest
• [x] 17 😐 Letter Combinations of a Phone Number .swift
• [ ] 18 😐 4Sum
• [x] 19 😐 Remove Nth Node From End of List .swift
• [x] 20 😎 Valid Parentheses .swift
• [x] 21 😎 Merge Two Sorted Lists .swift
• [ ] 22 😐 Generate Parentheses
• [ ] 23 😨 Merge k Sorted Lists
• [ ] 24 😐 Swap Nodes in Pairs
• [ ] 25 😨 Reverse Nodes in k-Group
• [x] 26 😎 Remove Duplicates from Sorted Array .swift
• [x] 27 😎 Remove Element .swift
• [x] 28 😎 Implement strStr() .swift
• [ ] 29 😐 Divide Two Integers
• [ ] 30 😨 Substring with Concatenation of All Words
• [ ] 31 😐 Next Permutation
• [ ] 32 😨 Longest Valid Parentheses
• [ ] 33 😐 Search in Rotated Sorted Array
• [ ] 34 😐 Find First and Last Position of Element in Sorted Array
• [x] 35 😎 Search Insert Position .swift
• [ ] 36 😐 Valid Sudoku
• [ ] 37 😨 Sudoku Solver
• [x] 38 😎 Count and Say .swift
• [ ] 39 😐 Combination Sum
• [ ] 40 😐 Combination Sum II
• [ ] 41 😨 First Missing Positive
• [ ] 42 😨 Trapping Rain Water
• [ ] 43 😐 Multiply Strings
• [ ] 44 😨 Wildcard Matching
• [ ] 45 😨 Jump Game II
• [ ] 46 😐 Permutations
• [ ] 47 😐 Permutations II
• [ ] 48 😐 Rotate Image
• [x] 49 😐 Group Anagrams .swift
• [ ] 50 😐 Pow(x, n)
• [ ] 51 😨 N-Queens
• [ ] 52 😨 N-Queens II
• [ ] 53 😎 Maximum Subarray
• [ ] 54 😐 Spiral Matrix
• [ ] 55 😐 Jump Game
• [ ] 56 😐 Merge Intervals
• [ ] 57 😨 Insert Interval
• [x] 58 😎 Length of Last Word .swift
• [ ] 59 😐 Spiral Matrix II
• [ ] 60 😐 Permutation Sequence
• [ ] 61 😐 Rotate List
• [ ] 62 😐 Unique Paths
• [ ] 63 😐 Unique Paths II
• [ ] 64 😐 Minimum Path Sum
• [x] 65 😨 Valid Number .swift
• [x] 66 😎 Plus One .swift
• [x] 67 😎 Add Binary .swift
• [ ] 68 😨 Text Justification
• [ ] 69 😎 Sqrt(x)
• [ ] 70 😎 Climbing Stairs
• [ ] 71 😐 Simplify Path
• [ ] 72 😨 Edit Distance
• [ ] 73 😐 Set Matrix Zeroes
• [ ] 74 😐 Search a 2D Matrix
• [ ] 75 😐 Sort Colors
• [ ] 76 😨 Minimum Window Substring
• [ ] 77 😐 Combinations
• [ ] 78 😐 Subsets
• [ ] 79 😐 Word Search
• [ ] 80 😐 Remove Duplicates from Sorted Array II
• [ ] 81 😐 Search in Rotated Sorted Array II
• [x] 82 😐 Remove Duplicates from Sorted List II .swift
• [x] 83 😎 Remove Duplicates from Sorted List .swift
• [ ] 84 😨 Largest Rectangle in Histogram
• [ ] 85 😨 Maximal Rectangle
• [ ] 86 😐 Partition List
• [ ] 87 😨 Scramble String
• [x] 88 😎 Merge Sorted Array .swift
• [ ] 89 😐 Gray Code
• [ ] 90 😐 Subsets II
• [ ] 91 😐 Decode Ways
• [ ] 92 😐 Reverse Linked List II
• [ ] 93 😐 Restore IP Addresses
• [ ] 94 😐 Binary Tree Inorder Traversal
• [ ] 95 😐 Unique Binary Search Trees II
• [ ] 96 😐 Unique Binary Search Trees
• [ ] 97 😨 Interleaving String
• [ ] 98 😐 Validate Binary Search Tree
• [ ] 99 😨 Recover Binary Search Tree
• [x] 100 😎 Same Tree .swift
• [x] 101 😎 Symmetric Tree .swift
• [ ] 102 😐 Binary Tree Level Order Traversal
• [ ] 103 😐 Binary Tree Zigzag Level Order Traversal
• [x] 104 😎 Maximum Depth of Binary Tree .swift
• [ ] 105 😐 Construct Binary Tree from Preorder and Inorder Traversal
• [ ] 106 😐 Construct Binary Tree from Inorder and Postorder Traversal
• [ ] 107 😎 Binary Tree Level Order Traversal II
• [ ] 108 😎 Convert Sorted Array to Binary Search Tree
• [ ] 109 😐 Convert Sorted List to Binary Search Tree
• [x] 110 😎 Balanced Binary Tree .swift
• [x] 111 😎 Minimum Depth of Binary Tree .swift
• [ ] 112 😎 Path Sum
• [ ] 113 😐 Path Sum II
• [x] 114 😐 Flatten Binary Tree to Linked List .swift
• [ ] 115 😨 Distinct Subsequences
• [ ] 116 😐 Populating Next Right Pointers in Each Node
• [ ] 117 😐 Populating Next Right Pointers in Each Node II
• [ ] 118 😎 Pascal's Triangle
• [ ] 119 😎 Pascal's Triangle II
• [ ] 120 😐 Triangle
• [ ] 121 😎 Best Time to Buy and Sell Stock
• [ ] 122 😎 Best Time to Buy and Sell Stock II
• [ ] 123 😨 Best Time to Buy and Sell Stock III
• [ ] 124 😨 Binary Tree Maximum Path Sum
• [ ] 125 😎 Valid Palindrome
• [ ] 126 😨 Word Ladder II
• [ ] 127 😐 Word Ladder
• [ ] 128 😨 Longest Consecutive Sequence
• [ ] 129 😐 Sum Root to Leaf Numbers
• [ ] 130 😐 Surrounded Regions
• [ ] 131 😐 Palindrome Partitioning
• [ ] 132 😨 Palindrome Partitioning II
• [ ] 133 😐 Clone Graph
• [ ] 134 😐 Gas Station
• [ ] 135 😨 Candy
• [x] 136 😎 Single Number .swift
• [ ] 137 😐 Single Number II
• [ ] 138 😐 Copy List with Random Pointer
• [ ] 139 😐 Word Break
• [ ] 140 😨 Word Break II
• [ ] 141 😎 Linked List Cycle
• [ ] 142 😐 Linked List Cycle II
• [ ] 143 😐 Reorder List
• [ ] 144 😐 Binary Tree Preorder Traversal
• [ ] 145 😨 Binary Tree Postorder Traversal
• [ ] 146 😨 LRU Cache
• [ ] 147 😐 Insertion Sort List
• [ ] 148 😐 Sort List
• [ ] 149 😨 Max Points on a Line
• [ ] 150 😐 Evaluate Reverse Polish Notation
• [ ] 151 😐 Reverse Words in a String
• [ ] 152 😐 Maximum Product Subarray
• [ ] 153 😐 Find Minimum in Rotated Sorted Array
• [ ] 154 😨 Find Minimum in Rotated Sorted Array II
• [x] 155 😎 Min Stack .swift
• [ ] 156 😐 Binary Tree Upside Down ㊙️
• [ ] 157 😎 Read N Characters Given Read4 ㊙️
• [ ] 158 😨 Read N Characters Given Read4 II - Call multiple times ㊙️
• [ ] 159 😨 Longest Substring with At Most Two Distinct Characters ㊙️
• [ ] 160 😎 Intersection of Two Linked Lists
• [ ] 161 😐 One Edit Distance ㊙️
• [ ] 162 😐 Find Peak Element
• [ ] 163 😐 Missing Ranges ㊙️
• [ ] 164 😨 Maximum Gap
• [x] 165 😐 Compare Version Numbers .swift
• [ ] 166 😐 Fraction to Recurring Decimal
• [ ] 167 😎 Two Sum II - Input array is sorted
• [ ] 168 😎 Excel Sheet Column Title
• [ ] 169 😎 Majority Element
• [ ] 170 😎 Two Sum III - Data structure design ㊙️
• [ ] 171 😎 Excel Sheet Column Number
• [ ] 172 😎 Factorial Trailing Zeroes
• [ ] 173 😐 Binary Search Tree Iterator
• [ ] 174 😨 Dungeon Game
• [ ] 179 😐 Largest Number
• [ ] 186 😐 Reverse Words in a String II ㊙️
• [ ] 187 😐 Repeated DNA Sequences
• [ ] 188 😨 Best Time to Buy and Sell Stock IV
• [x] 189 😎 Rotate Array .swift
• [ ] 190 😎 Reverse Bits
• [ ] 191 😎 Number of 1 Bits
• [ ] 198 😎 House Robber
• [ ] 199 😐 Binary Tree Right Side View
• [ ] 200 😐 Number of Islands
• [ ] 201 😐 Bitwise AND of Numbers Range
• [ ] 202 😎 Happy Number
• [ ] 203 😎 Remove Linked List Elements
• [ ] 204 😎 Count Primes
• [ ] 205 😎 Isomorphic Strings
• [ ] 206 😎 Reverse Linked List
• [ ] 207 😐 Course Schedule
• [ ] 208 😐 Implement Trie (Prefix Tree)
• [ ] 209 😐 Minimum Size Subarray Sum
• [ ] 210 😐 Course Schedule II
• [ ] 211 😐 Add and Search Word - Data structure design
• [ ] 212 😨 Word Search II
• [ ] 213 😐 House Robber II
• [ ] 214 😨 Shortest Palindrome
• [ ] 215 😐 Kth Largest Element in an Array
• [ ] 216 😐 Combination Sum III
• [ ] 217 😎 Contains Duplicate
• [ ] 218 😨 The Skyline Problem
• [ ] 219 😎 Contains Duplicate II
• [ ] 220 😐 Contains Duplicate III
• [ ] 221 😐 Maximal Square
• [ ] 222 😐 Count Complete Tree Nodes
• [ ] 223 😐 Rectangle Area
• [ ] 224 😨 Basic Calculator
• [ ] 225 😎 Implement Stack using Queues
• [x] 226 😎 Invert Binary Tree .swift
• [ ] 227 😐 Basic Calculator II
• [ ] 228 😐 Summary Ranges
• [ ] 229 😐 Majority Element II
• [ ] 230 😐 Kth Smallest Element in a BST
• [ ] 231 😎 Power of Two
• [ ] 232 😎 Implement Queue using Stacks
• [ ] 233 😨 Number of Digit One
• [ ] 234 😎 Palindrome Linked List
• [ ] 235 😎 Lowest Common Ancestor of a Binary Search Tree
• [ ] 236 😐 Lowest Common Ancestor of a Binary Tree
• [ ] 237 😎 Delete Node in a Linked List
• [ ] 238 😐 Product of Array Except Self
• [ ] 239 😨 Sliding Window Maximum
• [ ] 240 😐 Search a 2D Matrix II
• [ ] 241 😐 Different Ways to Add Parentheses
• [x] 242 😎 Valid Anagram .swift
• [ ] 243 😎 Shortest Word Distance ㊙️
• [ ] 244 😐 Shortest Word Distance II ㊙️
• [ ] 245 😐 Shortest Word Distance III ㊙️
• [ ] 246 😎 Strobogrammatic Number ㊙️
• [ ] 247 😐 Strobogrammatic Number II ㊙️
• [ ] 248 😨 Strobogrammatic Number III ㊙️
• [ ] 249 😐 Group Shifted Strings ㊙️
• [ ] 250 😐 Count Univalue Subtrees ㊙️
• [ ] 251 😐 Flatten 2D Vector ㊙️
• [ ] 252 😎 Meeting Rooms ㊙️
• [ ] 253 😐 Meeting Rooms II ㊙️
• [ ] 254 😐 Factor Combinations ㊙️
• [ ] 255 😐 Verify Preorder Sequence in Binary Search Tree ㊙️
• [ ] 256 😎 Paint House ㊙️
• [ ] 257 😎 Binary Tree Paths
• [x] 258 😎 Add Digits .swift
• [ ] 259 😐 3Sum Smaller ㊙️
• [ ] 260 😐 Single Number III
• [ ] 261 😐 Graph Valid Tree ㊙️
• [x] 263 😎 Ugly Number .swift
• [ ] 264 😐 Ugly Number II
• [ ] 265 😨 Paint House II ㊙️
• [ ] 266 😎 Palindrome Permutation ㊙️
• [ ] 267 😐 Palindrome Permutation II ㊙️
• [x] 268 😎 Missing Number .swift
• [ ] 269 😨 Alien Dictionary ㊙️
• [ ] 270 😎 Closest Binary Search Tree Value ㊙️
• [ ] 271 😐 Encode and Decode Strings ㊙️
• [ ] 272 😨 Closest Binary Search Tree Value II ㊙️
• [ ] 273 😨 Integer to English Words
• [ ] 274 😐 H-Index
• [ ] 275 😐 H-Index II
• [ ] 276 😎 Paint Fence ㊙️
• [ ] 277 😐 Find the Celebrity ㊙️
• [ ] 278 😎 First Bad Version
• [ ] 279 😐 Perfect Squares
• [ ] 280 😐 Wiggle Sort ㊙️
• [ ] 281 😐 Zigzag Iterator ㊙️
• [ ] 282 😨 Expression Add Operators
• [x] 283 😎 Move Zeroes .swift
• [ ] 284 😐 Peeking Iterator
• [ ] 285 😐 Inorder Successor in BST ㊙️
• [ ] 286 😐 Walls and Gates ㊙️
• [ ] 287 😐 Find the Duplicate Number
• [ ] 288 😐 Unique Word Abbreviation ㊙️
• [ ] 289 😐 Game of Life
• [ ] 290 😎 Word Pattern
• [ ] 291 😨 Word Pattern II ㊙️
• [ ] 292 😎 Nim Game
• [ ] 293 😎 Flip Game ㊙️
• [ ] 294 😐 Flip Game II ㊙️
• [ ] 295 😨 Find Median from Data Stream
• [ ] 296 😨 Best Meeting Point ㊙️
• [ ] 297 😨 Serialize and Deserialize Binary Tree
• [ ] 298 😐 Binary Tree Longest Consecutive Sequence ㊙️
• [ ] 299 😐 Bulls and Cows
• [ ] 300 😐 Longest Increasing Subsequence
• [ ] 301 😨 Remove Invalid Parentheses
• [ ] 302 😨 Smallest Rectangle Enclosing Black Pixels ㊙️
• [ ] 303 😎 Range Sum Query - Immutable
• [ ] 304 😐 Range Sum Query 2D - Immutable
• [ ] 305 😨 Number of Islands II ㊙️
• [ ] 306 😐 Additive Number
• [ ] 307 😐 Range Sum Query - Mutable
• [ ] 308 😨 Range Sum Query 2D - Mutable ㊙️
• [ ] 309 😐 Best Time to Buy and Sell Stock with Cooldown
• [ ] 310 😐 Minimum Height Trees
• [ ] 311 😐 Sparse Matrix Multiplication ㊙️
• [ ] 312 😨 Burst Balloons
• [ ] 313 😐 Super Ugly Number
• [ ] 314 😐 Binary Tree Vertical Order Traversal ㊙️
• [ ] 315 😨 Count of Smaller Numbers After Self
• [ ] 316 😨 Remove Duplicate Letters
• [ ] 317 😨 Shortest Distance from All Buildings ㊙️
• [ ] 318 😐 Maximum Product of Word Lengths
• [ ] 319 😐 Bulb Switcher
• [ ] 320 😐 Generalized Abbreviation ㊙️
• [ ] 321 😨 Create Maximum Number
• [ ] 322 😐 Coin Change
• [ ] 323 😐 Number of Connected Components in an Undirected Graph ㊙️
• [ ] 324 😐 Wiggle Sort II
• [ ] 325 😐 Maximum Size Subarray Sum Equals k ㊙️
• [x] 326 😎 Power of Three .swift
• [ ] 327 😨 Count of Range Sum
• [ ] 328 😐 Odd Even Linked List
• [ ] 329 😨 Longest Increasing Path in a Matrix
• [ ] 330 😨 Patching Array
• [ ] 331 😐 Verify Preorder Serialization of a Binary Tree
• [ ] 332 😐 Reconstruct Itinerary
• [ ] 333 😐 Largest BST Subtree ㊙️
• [ ] 334 😐 Increasing Triplet Subsequence
• [ ] 335 😨 Self Crossing
• [ ] 336 😨 Palindrome Pairs
• [ ] 337 😐 House Robber III
• [ ] 338 😐 Counting Bits
• [ ] 339 😎 Nested List Weight Sum ㊙️
• [ ] 340 😨 Longest Substring with At Most K Distinct Characters ㊙️
• [ ] 341 😐 Flatten Nested List Iterator
• [ ] 342 😎 Power of Four
• [ ] 343 😐 Integer Break
• [ ] 344 😎 Reverse String
• [ ] 345 😎 Reverse Vowels of a String
• [ ] 346 😎 Moving Average from Data Stream ㊙️
• [ ] 347 😐 Top K Frequent Elements
• [ ] 348 😐 Design Tic-Tac-Toe ㊙️
• [ ] 349 😎 Intersection of Two Arrays
• [ ] 350 😎 Intersection of Two Arrays II
• [ ] 351 😐 Android Unlock Patterns ㊙️
• [ ] 352 😨 Data Stream as Disjoint Intervals
• [ ] 353 😐 Design Snake Game ㊙️
• [ ] 354 😨 Russian Doll Envelopes
• [ ] 355 😐 Design Twitter
• [ ] 356 😐 Line Reflection ㊙️
• [ ] 357 😐 Count Numbers with Unique Digits
• [ ] 358 😨 Rearrange String k Distance Apart ㊙️
• [ ] 359 😎 Logger Rate Limiter ㊙️
• [ ] 360 😐 Sort Transformed Array ㊙️
• [ ] 361 😐 Bomb Enemy ㊙️
• [ ] 362 😐 Design Hit Counter ㊙️
• [ ] 363 😨 Max Sum of Rectangle No Larger Than K
• [ ] 364 😐 Nested List Weight Sum II ㊙️
• [ ] 365 😐 Water and Jug Problem
• [ ] 366 😐 Find Leaves of Binary Tree ㊙️
• [ ] 367 😎 Valid Perfect Square
• [ ] 368 😐 Largest Divisible Subset
• [ ] 369 😐 Plus One Linked List ㊙️
• [ ] 370 😐 Range Addition ㊙️
• [ ] 371 😎 Sum of Two Integers
• [ ] 372 😐 Super Pow
• [ ] 373 😐 Find K Pairs with Smallest Sums
• [ ] 374 😎 Guess Number Higher or Lower
• [ ] 375 😐 Guess Number Higher or Lower II
• [ ] 376 😐 Wiggle Subsequence
• [ ] 377 😐 Combination Sum IV
• [ ] 378 😐 Kth Smallest Element in a Sorted Matrix
• [ ] 379 😐 Design Phone Directory ㊙️
• [ ] 380 😐 Insert Delete GetRandom O(1)
• [ ] 381 😨 Insert Delete GetRandom O(1) - Duplicates allowed
• [ ] 382 😐 Linked List Random Node
• [ ] 383 😎 Ransom Note
• [ ] 384 😐 Shuffle an Array
• [ ] 385 😐 Mini Parser
• [ ] 386 😐 Lexicographical Numbers
• [ ] 387 😎 First Unique Character in a String
• [ ] 388 😐 Longest Absolute File Path
• [ ] 389 😎 Find the Difference
• [ ] 390 😐 Elimination Game
• [ ] 391 😨 Perfect Rectangle
• [ ] 392 😐 Is Subsequence
• [ ] 393 😐 UTF-8 Validation
• [ ] 394 😐 Decode String
• [ ] 395 😐 Longest Substring with At Least K Repeating Characters
• [ ] 396 😐 Rotate Function
• [ ] 397 😐 Integer Replacement
• [ ] 398 😐 Random Pick Index
• [ ] 399 😐 Evaluate Division
• [ ] 400 😎 Nth Digit
• [ ] 401 😎 Binary Watch
• [ ] 402 😐 Remove K Digits
• [ ] 403 😨 Frog Jump
• [ ] 404 😎 Sum of Left Leaves
• [ ] 405 😎 Convert a Number to Hexadecimal
• [ ] 406 😐 Queue Reconstruction by Height
• [ ] 407 😨 Trapping Rain Water II
• [ ] 408 😎 Valid Word Abbreviation ㊙️
• [ ] 409 😎 Longest Palindrome
• [ ] 410 😨 Split Array Largest Sum
• [ ] 411 😨 Minimum Unique Word Abbreviation ㊙️
• [ ] 412 😎 Fizz Buzz
• [ ] 413 😐 Arithmetic Slices
• [ ] 414 😎 Third Maximum Number
• [ ] 415 😎 Add Strings
• [ ] 416 😐 Partition Equal Subset Sum
• [ ] 417 😐 Pacific Atlantic Water Flow
• [ ] 418 😐 Sentence Screen Fitting ㊙️
• [ ] 419 😐 Battleships in a Board
• [ ] 420 😨 Strong Password Checker
• [ ] 421 😐 Maximum XOR of Two Numbers in an Array
• [ ] 422 😎 Valid Word Square ㊙️
• [ ] 423 😐 Reconstruct Original Digits from English
• [ ] 424 😐 Longest Repeating Character Replacement
• [ ] 425 😨 Word Squares ㊙️
• [ ] 432 😨 All O`one Data Structure
• [ ] 433 😐 Minimum Genetic Mutation
• [ ] 434 😎 Number of Segments in a String
• [ ] 435 😐 Non-overlapping Intervals
• [ ] 436 😐 Find Right Interval
• [ ] 437 😎 Path Sum III
• [ ] 438 😎 Find All Anagrams in a String
• [ ] 439 😐 Ternary Expression Parser ㊙️
• [ ] 440 😨 K-th Smallest in Lexicographical Order
• [ ] 441 😎 Arranging Coins
• [ ] 442 😐 Find All Duplicates in an Array
• [ ] 443 😎 String Compression
• [ ] 444 😐 Sequence Reconstruction ㊙️
• [ ] 445 😐 Add Two Numbers II
• [ ] 446 😨 Arithmetic Slices II - Subsequence
• [ ] 447 😎 Number of Boomerangs
• [ ] 448 😎 Find All Numbers Disappeared in an Array
• [ ] 449 😐 Serialize and Deserialize BST
• [ ] 450 😐 Delete Node in a BST
• [ ] 451 😐 Sort Characters By Frequency
• [ ] 452 😐 Minimum Number of Arrows to Burst Balloons
• [ ] 453 😎 Minimum Moves to Equal Array Elements
• [ ] 454 😐 4Sum II
• [ ] 455 😎 Assign Cookies
• [ ] 456 😐 132 Pattern
• [ ] 457 😐 Circular Array Loop
• [ ] 458 😎 Poor Pigs
• [ ] 459 😎 Repeated Substring Pattern
• [ ] 460 😨 LFU Cache
• [x] 461 😎 Hamming Distance .swift
• [ ] 462 😐 Minimum Moves to Equal Array Elements II
• [ ] 463 😎 Island Perimeter
• [ ] 464 😐 Can I Win
• [ ] 465 😨 Optimal Account Balancing ㊙️
• [ ] 466 😨 Count The Repetitions
• [ ] 467 😐 Unique Substrings in Wraparound String
• [ ] 468 😐 Validate IP Address
• [ ] 469 😐 Convex Polygon ㊙️
• [ ] 471 😨 Encode String with Shortest Length ㊙️
• [ ] 472 😨 Concatenated Words
• [ ] 473 😐 Matchsticks to Square
• [ ] 474 😐 Ones and Zeroes
• [ ] 475 😎 Heaters
• [x] 476 😎 Number Complement .swift
• [ ] 477 😐 Total Hamming Distance
• [ ] 479 😎 Largest Palindrome Product
• [ ] 480 😨 Sliding Window Median
• [ ] 481 😐 Magical String
• [ ] 482 😎 License Key Formatting
• [ ] 483 😨 Smallest Good Base
• [ ] 484 😐 Find Permutation ㊙️
• [ ] 485 😎 Max Consecutive Ones
• [ ] 486 😐 Predict the Winner
• [ ] 487 😐 Max Consecutive Ones II ㊙️
• [ ] 488 😨 Zuma Game
• [ ] 490 😐 The Maze ㊙️
• [ ] 491 😐 Increasing Subsequences
• [ ] 492 😎 Construct the Rectangle
• [ ] 493 😨 Reverse Pairs
• [ ] 494 😐 Target Sum
• [ ] 495 😐 Teemo Attacking
• [ ] 496 😎 Next Greater Element I
• [ ] 498 😐 Diagonal Traverse
• [ ] 499 😨 The Maze III ㊙️
• [ ] 500 😎 Keyboard Row
• [ ] 501 😎 Find Mode in Binary Search Tree
• [ ] 502 😨 IPO
• [ ] 503 😐 Next Greater Element II
• [x] 504 😎 Base 7 .swift
• [ ] 505 😐 The Maze II ㊙️
• [ ] 506 😎 Relative Ranks
• [ ] 507 😎 Perfect Number
• [ ] 508 😐 Most Frequent Subtree Sum
• [ ] 513 😐 Find Bottom Left Tree Value
• [ ] 514 😨 Freedom Trail
• [ ] 515 😐 Find Largest Value in Each Tree Row
• [ ] 516 😐 Longest Palindromic Subsequence
• [ ] 517 😨 Super Washing Machines
• [ ] 518 😐 Coin Change 2
• [x] 520 😎 Detect Capital .swift
• [ ] 521 😎 Longest Uncommon Subsequence I
• [ ] 522 😐 Longest Uncommon Subsequence II
• [ ] 523 😐 Continuous Subarray Sum
• [ ] 524 😐 Longest Word in Dictionary through Deleting
• [ ] 525 😐 Contiguous Array
• [ ] 526 😐 Beautiful Arrangement
• [ ] 527 😨 Word Abbreviation ㊙️
• [ ] 529 😐 Minesweeper
• [ ] 530 😎 Minimum Absolute Difference in BST
• [ ] 531 😐 Lonely Pixel I ㊙️
• [ ] 532 😎 K-diff Pairs in an Array
• [ ] 533 😐 Lonely Pixel II ㊙️
• [ ] 535 😐 Encode and Decode TinyURL
• [ ] 536 😐 Construct Binary Tree from String ㊙️
• [ ] 537 😐 Complex Number Multiplication
• [ ] 538 😎 Convert BST to Greater Tree
• [ ] 539 😐 Minimum Time Difference
• [ ] 540 😐 Single Element in a Sorted Array
• [ ] 541 😎 Reverse String II
• [ ] 542 😐 01 Matrix
• [ ] 543 😎 Diameter of Binary Tree
• [ ] 544 😐 Output Contest Matches ㊙️
• [ ] 545 😐 Boundary of Binary Tree ㊙️
• [ ] 546 😨 Remove Boxes
• [ ] 547 😐 Friend Circles
• [ ] 548 😐 Split Array with Equal Sum ㊙️
• [ ] 549 😐 Binary Tree Longest Consecutive Sequence II ㊙️
• [ ] 551 😎 Student Attendance Record I
• [ ] 552 😨 Student Attendance Record II
• [ ] 553 😐 Optimal Division
• [ ] 554 😐 Brick Wall
• [ ] 555 😐 Split Concatenated Strings ㊙️
• [ ] 556 😐 Next Greater Element III
• [ ] 557 😎 Reverse Words in a String III
• [ ] 560 😐 Subarray Sum Equals K
• [ ] 561 😎 Array Partition I
• [ ] 562 😐 Longest Line of Consecutive One in Matrix ㊙️
• [ ] 563 😎 Binary Tree Tilt
• [ ] 564 😨 Find the Closest Palindrome
• [ ] 565 😐 Array Nesting
• [ ] 566 😎 Reshape the Matrix
• [ ] 567 😐 Permutation in String
• [ ] 568 😨 Maximum Vacation Days ㊙️
• [ ] 572 😎 Subtree of Another Tree
• [ ] 573 😐 Squirrel Simulation ㊙️
• [ ] 575 😎 Distribute Candies
• [ ] 576 😐 Out of Boundary Paths
• [ ] 581 😎 Shortest Unsorted Continuous Subarray
• [ ] 582 😐 Kill Process ㊙️
• [ ] 583 😐 Delete Operation for Two Strings
• [ ] 587 😨 Erect the Fence
• [ ] 588 😨 Design In-Memory File System ㊙️
• [ ] 591 😨 Tag Validator
• [ ] 592 😐 Fraction Addition and Subtraction
• [ ] 593 😐 Valid Square
• [ ] 594 😎 Longest Harmonious Subsequence
• [ ] 598 😎 Range Addition II
• [ ] 599 😎 Minimum Index Sum of Two Lists
• [ ] 600 😨 Non-negative Integers without Consecutive Ones
• [ ] 604 😎 Design Compressed String Iterator ㊙️
• [ ] 605 😎 Can Place Flowers
• [ ] 606 😎 Construct String from Binary Tree
• [ ] 609 😐 Find Duplicate File in System
• [ ] 611 😐 Valid Triangle Number
• [ ] 616 😐 Add Bold Tag in String ㊙️
• [ ] 617 😎 Merge Two Binary Trees
• [ ] 621 😐 Task Scheduler
• [ ] 623 😐 Add One Row to Tree
• [ ] 624 😎 Maximum Distance in Arrays ㊙️
• [ ] 625 😐 Minimum Factorization ㊙️
• [ ] 628 😎 Maximum Product of Three Numbers
• [ ] 629 😨 K Inverse Pairs Array
• [ ] 630 😨 Course Schedule III
• [ ] 631 😨 Design Excel Sum Formula ㊙️
• [ ] 632 😨 Smallest Range
• [ ] 633 😎 Sum of Square Numbers
• [ ] 634 😐 Find the Derangement of An Array ㊙️
• [ ] 635 😐 Design Log Storage System ㊙️
• [ ] 636 😐 Exclusive Time of Functions
• [ ] 637 😎 Average of Levels in Binary Tree
• [ ] 638 😐 Shopping Offers
• [ ] 639 😨 Decode Ways II
• [ ] 640 😐 Solve the Equation
• [ ] 642 😨 Design Search Autocomplete System ㊙️
• [ ] 643 😎 Maximum Average Subarray I
• [ ] 644 😨 Maximum Average Subarray II ㊙️
• [ ] 645 😎 Set Mismatch
• [ ] 646 😐 Maximum Length of Pair Chain
• [ ] 647 😐 Palindromic Substrings
• [ ] 648 😐 Replace Words
• [ ] 649 😐 Dota2 Senate
• [ ] 650 😐 2 Keys Keyboard
• [ ] 651 😐 4 Keys Keyboard ㊙️
• [ ] 652 😐 Find Duplicate Subtrees
• [ ] 653 😎 Two Sum IV - Input is a BST
• [ ] 654 😐 Maximum Binary Tree
• [ ] 655 😐 Print Binary Tree
• [ ] 656 😨 Coin Path ㊙️
• [ ] 657 😎 Judge Route Circle
• [ ] 658 😐 Find K Closest Elements
• [ ] 659 😐 Split Array into Consecutive Subsequences
• [ ] 660 😨 Remove 9 ㊙️
• [ ] 661 😎 Image Smoother
• [ ] 662 😐 Maximum Width of Binary Tree
• [ ] 663 😐 Equal Tree Partition ㊙️
• [ ] 664 😨 Strange Printer
• [ ] 665 😎 Non-decreasing Array
• [ ] 666 😐 Path Sum IV ㊙️
• [ ] 667 😐 Beautiful Arrangement II
• [ ] 668 😨 Kth Smallest Number in Multiplication Table
• [ ] 669 😎 Trim a Binary Search Tree
• [ ] 670 😐 Maximum Swap
• [ ] 671 😎 Second Minimum Node In a Binary Tree
• [ ] 672 😐 Bulb Switcher II
• [ ] 673 😐 Number of Longest Increasing Subsequence
• [ ] 674 😎 Longest Continuous Increasing Subsequence
• [ ] 675 😨 Cut Off Trees for Golf Event
• [ ] 676 😐 Implement Magic Dictionary
• [ ] 677 😐 Map Sum Pairs
• [ ] 678 😐 Valid Parenthesis String
• [ ] 679 😨 24 Game
• [ ] 680 😎 Valid Palindrome II
• [ ] 681 😐 Next Closest Time ㊙️
• [ ] 682 😎 Baseball Game
• [ ] 683 😨 K Empty Slots ㊙️
• [ ] 684 😐 Redundant Connection
• [ ] 685 😨 Redundant Connection II
• [ ] 686 😎 Repeated String Match
• [ ] 687 😎 Longest Univalue Path
• [ ] 688 😐 Knight Probability in Chessboard
• [ ] 689 😨 Maximum Sum of 3 Non-Overlapping Subarrays
• [ ] 690 😎 Employee Importance
• [ ] 691 😨 Stickers to Spell Word
• [ ] 692 😐 Top K Frequent Words
• [ ] 693 😎 Binary Number with Alternating Bits
• [ ] 694 😐 Number of Distinct Islands ㊙️
• [ ] 695 😎 Max Area of Island
• [ ] 696 😎 Count Binary Substrings
• [ ] 697 😎 Degree of an Array
• [ ] 698 😐 Partition to K Equal Sum Subsets
• [ ] 699 😨 Falling Squares
• [ ] 711 😨 Number of Distinct Islands II ㊙️
• [ ] 712 😐 Minimum ASCII Delete Sum for Two Strings
• [ ] 713 😐 Subarray Product Less Than K
• [ ] 714 😐 Best Time to Buy and Sell Stock with Transaction Fee
• [ ] 715 😨 Range Module
• [ ] 716 😨 Max Stack ㊙️
• [ ] 717 😎 1-bit and 2-bit Characters
• [ ] 718 😐 Maximum Length of Repeated Subarray
• [ ] 719 😨 Find K-th Smallest Pair Distance
• [ ] 720 😎 Longest Word in Dictionary
• [ ] 721 😐 Accounts Merge
• [ ] 722 😐 Remove Comments
• [ ] 723 😐 Candy Crush ㊙️
• [ ] 724 😎 Find Pivot Index
• [ ] 725 😐 Split Linked List in Parts
• [ ] 726 😨 Number of Atoms
• [ ] 727 😨 Minimum Window Subsequence ㊙️
• [ ] 728 😎 Self Dividing Numbers
• [ ] 729 😐 My Calendar I
• [ ] 730 😨 Count Different Palindromic Subsequences
• [ ] 731 😐 My Calendar II
• [ ] 732 😨 My Calendar III
• [ ] 733 😎 Flood Fill
• [ ] 734 😎 Sentence Similarity ㊙️
• [ ] 735 😐 Asteroid Collision
• [ ] 736 😨 Parse Lisp Expression
• [ ] 737 😐 Sentence Similarity II ㊙️
• [ ] 738 😐 Monotone Increasing Digits
• [ ] 739 😐 Daily Temperatures
• [ ] 740 😐 Delete and Earn
• [ ] 741 😨 Cherry Pickup
• [ ] 709 😎 To Lower Case
• [ ] 742 😐 Closest Leaf in a Binary Tree ㊙️
• [ ] 743 😐 Network Delay Time
• [ ] 744 😎 Find Smallest Letter Greater Than Target
• [ ] 745 😨 Prefix and Suffix Search
• [ ] 746 😎 Min Cost Climbing Stairs
• [ ] 747 😎 Largest Number At Least Twice of Others
• [ ] 748 😐 Shortest Completing Word
• [ ] 749 😨 Contain Virus
• [ ] 750 😐 Number Of Corner Rectangles ㊙️
• [ ] 751 😎 IP to CIDR ㊙️
• [ ] 752 😐 Open the Lock
• [ ] 753 😨 Cracking the Safe
• [ ] 754 😐 Reach a Number
• [ ] 755 😐 Pour Water ㊙️
• [ ] 756 😐 Pyramid Transition Matrix
• [ ] 426 😐 Convert Binary Search Tree to Sorted Doubly Linked List ㊙️
• [ ] 757 😨 Set Intersection Size At Least Two
• [ ] 758 😎 Bold Words in String ㊙️
• [ ] 759 😨 Employee Free Time ㊙️
• [ ] 760 😎 Find Anagram Mappings ㊙️
• [ ] 761 😨 Special Binary String
• [ ] 429 😎 N-ary Tree Level Order Traversal
• [ ] 428 😨 Serialize and Deserialize N-ary Tree ㊙️
• [ ] 430 😐 Flatten a Multilevel Doubly Linked List
• [ ] 762 😎 Prime Number of Set Bits in Binary Representation
• [ ] 763 😐 Partition Labels
• [ ] 764 😐 Largest Plus Sign
• [ ] 765 😨 Couples Holding Hands
• [ ] 431 😨 Encode N-ary Tree to Binary Tree ㊙️
• [ ] 427 😎 Construct Quad Tree
• [ ] 558 😎 Quad Tree Intersection
• [ ] 559 😎 Maximum Depth of N-ary Tree
• [ ] 589 😎 N-ary Tree Preorder Traversal
• [ ] 590 😎 N-ary Tree Postorder Traversal
• [ ] 766 😎 Toeplitz Matrix
• [ ] 767 😐 Reorganize String
• [ ] 768 😨 Max Chunks To Make Sorted II
• [ ] 769 😐 Max Chunks To Make Sorted
• [ ] 770 😨 Basic Calculator IV
• [ ] 771 😎 Jewels and Stones
• [ ] 700 😎 Search in a Binary Search Tree
• [ ] 701 😐 Insert into a Binary Search Tree
• [ ] 772 😨 Basic Calculator III ㊙️
• [ ] 702 😐 Search in a Sorted Array of Unknown Size ㊙️
• [ ] 773 😨 Sliding Puzzle
• [ ] 774 😨 Minimize Max Distance to Gas Station ㊙️
• [ ] 703 😎 Kth Largest Element in a Stream
• [ ] 775 😐 Global and Local Inversions
• [ ] 776 😐 Split BST ㊙️
• [ ] 704 😎 Binary Search
• [ ] 777 😐 Swap Adjacent in LR String
• [ ] 778 😨 Swim in Rising Water
• [ ] 779 😐 K-th Symbol in Grammar
• [ ] 780 😨 Reaching Points
• [ ] 781 😐 Rabbits in Forest
• [ ] 782 😨 Transform to Chessboard
• [ ] 783 😎 Minimum Distance Between BST Nodes
• [ ] 784 😎 Letter Case Permutation
• [ ] 785 😐 Is Graph Bipartite?
• [ ] 786 😨 K-th Smallest Prime Fraction
• [ ] 787 😐 Cheapest Flights Within K Stops
• [x] 788 😎 Rotated Digits .swift
• [ ] 789 😐 Escape The Ghosts
• [ ] 790 😐 Domino and Tromino Tiling
• [ ] 791 😐 Custom Sort String
• [ ] 792 😐 Number of Matching Subsequences
• [ ] 793 😨 Preimage Size of Factorial Zeroes Function
• [ ] 794 😐 Valid Tic-Tac-Toe State
• [ ] 795 😐 Number of Subarrays with Bounded Maximum
• [x] 796 😎 Rotate String .swift
• [ ] 797 😐 All Paths From Source to Target
• [ ] 798 😨 Smallest Rotation with Highest Score
• [ ] 799 😐 Champagne Tower
• [ ] 705 😎 Design HashSet
• [ ] 706 😎 Design HashMap
• [ ] 800 😎 Similar RGB Color ㊙️
• [ ] 801 😐 Minimum Swaps To Make Sequences Increasing
• [ ] 802 😐 Find Eventual Safe States
• [ ] 803 😨 Bricks Falling When Hit
• [x] 804 😎 Unique Morse Code Words .swift
• [ ] 805 😨 Split Array With Same Average
• [x] 806 😎 Number of Lines To Write String .swift
• [ ] 807 😐 Max Increase to Keep City Skyline
• [ ] 808 😐 Soup Servings
• [ ] 809 😐 Expressive Words
• [ ] 810 😨 Chalkboard XOR Game
• [x] 811 😎 Subdomain Visit Count .swift
• [ ] 812 😎 Largest Triangle Area
• [ ] 813 😐 Largest Sum of Averages
• [ ] 814 😐 Binary Tree Pruning
• [ ] 815 😨 Bus Routes
• [ ] 816 😐 Ambiguous Coordinates
• [ ] 817 😐 Linked List Components
• [ ] 818 😨 Race Car
• [x] 819 😎 Most Common Word .swift
• [ ] 707 😎 Design Linked List
• [ ] 820 😐 Short Encoding of Words
• [ ] 821 😎 Shortest Distance to a Character
• [ ] 822 😐 Card Flipping Game
• [ ] 823 😐 Binary Trees With Factors
• [ ] 708 😐 Insert into a Cyclic Sorted List ㊙️
• [x] 824 😎 Goat Latin .swift
• [ ] 825 😐 Friends Of Appropriate Ages
• [ ] 826 😐 Most Profit Assigning Work
• [ ] 827 😨 Making A Large Island
• [ ] 828 😨 Unique Letter String
• [ ] 829 😐 Consecutive Numbers Sum
• [x] 830 😎 Positions of Large Groups .swift
• [ ] 831 😐 Masking Personal Information
• [ ] 641 😐 Design Circular Deque
• [ ] 622 😐 Design Circular Queue
• [x] 832 😎 Flipping an Image .swift
• [ ] 833 😐 Find And Replace in String
• [ ] 834 😨 Sum of Distances in Tree
• [ ] 835 😐 Image Overlap
• [ ] 489 😨 Robot Room Cleaner ㊙️
• [x] 836 😎 Rectangle Overlap .swift
• [ ] 837 😐 New 21 Game
• [ ] 838 😐 Push Dominoes
• [ ] 839 😨 Similar String Groups
• [x] 840 😎 Magic Squares In Grid .swift
• [ ] 841 😐 Keys and Rooms
• [ ] 842 😐 Split Array into Fibonacci Sequence
• [ ] 843 😨 Guess the Word
• [x] 844 😎 Backspace String Compare .swift
• [ ] 845 😐 Longest Mountain in Array
• [ ] 846 😐 Hand of Straights
• [ ] 847 😨 Shortest Path Visiting All Nodes
• [ ] 848 😐 Shifting Letters
• [ ] 849 😎 Maximize Distance to Closest Person
• [ ] 850 😨 Rectangle Area II
• [ ] 851 😐 Loud and Rich
• [x] 852 😎 Peak Index in a Mountain Array .swift
• [ ] 853 😐 Car Fleet
• [ ] 854 😨 K-Similar Strings
• [ ] 855 😐 Exam Room
• [ ] 856 😐 Score of Parentheses
• [ ] 857 😨 Minimum Cost to Hire K Workers
• [ ] 858 😐 Mirror Reflection
• [x] 859 😎 Buddy Strings .swift
• [x] 860 😎 Lemonade Change .swift
• [ ] 861 😐 Score After Flipping Matrix
• [ ] 862 😨 Shortest Subarray with Sum at Least K
• [ ] 863 😐 All Nodes Distance K in Binary Tree
• [ ] 710 😨 Random Pick with Blacklist
• [ ] 864 😨 Shortest Path to Get All Keys
• [ ] 865 😐 Smallest Subtree with all the Deepest Nodes
• [ ] 866 😐 Prime Palindrome
• [ ] 867 😎 Transpose Matrix
• [x] 868 😎 Binary Gap .swift
• [ ] 869 😐 Reordered Power of 2
• [ ] 870 😐 Advantage Shuffle
• [ ] 871 😨 Minimum Number of Refueling Stops
• [ ] 470 😐 Implement Rand10() Using Rand7()

Unit tests

This is a test-driven project. You may press ⌘ + u in Xcode to invoke the tests. Or just rake in CLI.

License