LeetCode

  # Title Solution Explanation Difficulty
☐ 1 Two Sum Java Explanation Easy
☐ 2 Add Two Numbers Java Explanation Medium
☐ 3 Longest Substring Without Repeating Characters Java Explanation Medium
☐ 4 Median of Two Sorted Arrays Java Explanation Hard
☐ 5 Longest Palindromic Substring Java Explanation Medium
☐ 6 ZigZag Conversion Java Explanation Medium
☐ 7 Reverse Integer Java Explanation Easy
☐ 8 String to Integer (atoi) Java Explanation Medium
☐ 9 Palindrome Number Java Explanation Easy
☐ 10 Regular Expression Matching Java Explanation Hard
☐ 11 Container With Most Water Java Explanation Medium
☐ 12 Integer to Roman Java Explanation Medium
☐ 13 Roman to Integer Java Explanation Easy
☐ 14 Longest Common Prefix Java Explanation Easy
☐ 15 3Sum Java Explanation Medium
☐ 16 3Sum Closest Java Explanation Medium
☐ 17 Letter Combinations of a Phone Number Java Explanation Medium
☐ 18 4Sum Java Explanation Medium
☐ 19 Remove Nth Node From End of List Java Explanation Medium
☐ 20 Valid Parentheses Java Explanation Easy
☐ 21 Merge Two Sorted Lists Java Explanation Easy
☐ 22 Generate Parentheses Java Explanation Medium
☐ 23 Merge k Sorted Lists Java Explanation Hard
☐ 24 Swap Nodes in Pairs Java Explanation Medium
☐ 25 Reverse Nodes in k-Group Java Explanation Hard
☐ 26 Remove Duplicates from Sorted Array Java Explanation Easy
☐ 27 Remove Element Java Explanation Easy
☐ 28 Implement strStr() Java Explanation Easy
☐ 29 Divide Two Integers Java Explanation Medium
☐ 30 Substring with Concatenation of All Words Java Explanation Hard
☐ 31 Next Permutation Java Explanation Medium
☐ 32 Longest Valid Parentheses Java Explanation Hard
☐ 33 Search in Rotated Sorted Array Java Explanation Medium
☐ 34 Find First and Last Position of Element in Sorted Array Java Explanation Medium
☐ 35 Search Insert Position Java Explanation Easy
☐ 36 Valid Sudoku Java Explanation Medium
☐ 37 Sudoku Solver Java Explanation Hard
☐ 38 Count and Say Java Explanation Easy
☐ 39 Combination Sum Java Explanation Medium
☐ 40 Combination Sum II Java Explanation Medium
☐ 41 First Missing Positive Java Explanation Hard
☐ 42 Trapping Rain Water Java Explanation Hard
☐ 43 Multiply Strings Java Explanation Medium
☐ 44 Wildcard Matching Java Explanation Hard
☐ 45 Jump Game II Java Explanation Hard
☐ 46 Permutations Java Explanation Medium
☐ 47 Permutations II Java Explanation Medium
☐ 48 Rotate Image Java Explanation Medium
☐ 49 Group Anagrams Java Explanation Medium
☐ 50 Pow(x, n) Java Explanation Medium
☐ 51 N-Queens Java Explanation Hard
☐ 52 N-Queens II Java Explanation Hard
☐ 53 Maximum Subarray Java Explanation Easy
☐ 54 Spiral Matrix Java Explanation Medium
☐ 55 Jump Game Java Explanation Medium
☐ 56 Merge Intervals Java Explanation Medium
☐ 57 Insert Interval Java Explanation Hard
☐ 58 Length of Last Word Java Explanation Easy
☐ 59 Spiral Matrix II Java Explanation Medium
☐ 60 Permutation Sequence Java Explanation Medium
☐ 61 Rotate List Java Explanation Medium
☐ 62 Unique Paths Java Explanation Medium
☐ 63 Unique Paths II Java Explanation Medium
☐ 64 Minimum Path Sum Java Explanation Medium
☐ 65 Valid Number Java Explanation Hard
☐ 66 Plus One Java Explanation Easy
☐ 67 Add Binary Java Explanation Easy
☐ 68 Text Justification Java Explanation Hard
☐ 69 Sqrt(x) Java Explanation Easy
☐ 70 Climbing Stairs Java Explanation Easy
☐ 71 Simplify Path Java Explanation Medium
☐ 72 Edit Distance Java Explanation Hard
☐ 73 Set Matrix Zeroes Java Explanation Medium
☐ 74 Search a 2D Matrix Java Explanation Medium
☐ 75 Sort Colors Java Explanation Medium
☐ 76 Minimum Window Substring Java Explanation Hard
☐ 77 Combinations Java Explanation Medium
☐ 78 Subsets Java Explanation Medium
☐ 79 Word Search Java Explanation Medium
☐ 80 Remove Duplicates from Sorted Array II Java Explanation Medium
☐ 81 Search in Rotated Sorted Array II Java Explanation Medium
☐ 82 Remove Duplicates from Sorted List II Java Explanation Medium
☐ 83 Remove Duplicates from Sorted List Java Explanation Easy
☐ 84 Largest Rectangle in Histogram Java Explanation Hard
☐ 85 Maximal Rectangle Java Explanation Hard
☐ 86 Partition List Java Explanation Medium
☐ 87 Scramble String Java Explanation Hard
☐ 88 Merge Sorted Array Java Explanation Easy
☐ 89 Gray Code Java Explanation Medium
☐ 90 Subsets II Java Explanation Medium
☐ 91 Decode Ways Java Explanation Medium
☐ 92 Reverse Linked List II Java Explanation Medium
☐ 93 Restore IP Addresses Java Explanation Medium
☐ 94 Binary Tree Inorder Traversal Java Explanation Medium
☐ 95 Unique Binary Search Trees II Java Explanation Medium
☐ 96 Unique Binary Search Trees Java Explanation Medium
☐ 97 Interleaving String Java Explanation Hard
☐ 98 Validate Binary Search Tree Java Explanation Medium
☐ 99 Recover Binary Search Tree Java Explanation Hard
☑ 100 Same Tree Java Explanation Easy
☐ 101 Symmetric Tree Java Explanation Easy
☐ 102 Binary Tree Level Order Traversal Java Explanation Medium
☐ 103 Binary Tree Zigzag Level Order Traversal Java Explanation Medium
☐ 104 Maximum Depth of Binary Tree Java Explanation Easy
☐ 105 Construct Binary Tree from Preorder and Inorder Traversal Java Explanation Medium
☐ 106 Construct Binary Tree from Inorder and Postorder Traversal Java Explanation Medium
☐ 107 Binary Tree Level Order Traversal II Java Explanation Easy
☐ 108 Convert Sorted Array to Binary Search Tree Java Explanation Easy
☐ 109 Convert Sorted List to Binary Search Tree Java Explanation Medium
☐ 110 Balanced Binary Tree Java Explanation Easy
☐ 111 Minimum Depth of Binary Tree Java Explanation Easy
☐ 112 Path Sum Java Explanation Easy
☐ 113 Path Sum II Java Explanation Medium
☐ 114 Flatten Binary Tree to Linked List Java Explanation Medium
☐ 115 Distinct Subsequences Java Explanation Hard
☐ 116 Populating Next Right Pointers in Each Node Java Explanation Medium
☐ 117 Populating Next Right Pointers in Each Node II Java Explanation Medium
☐ 118 Pascal’s Triangle Java Explanation Easy
☐ 119 Pascal’s Triangle II Java Explanation Easy
☐ 120 Triangle Java Explanation Medium
☐ 121 Best Time to Buy and Sell Stock Java Explanation Easy
☐ 122 Best Time to Buy and Sell Stock II Java Explanation Easy
☐ 123 Best Time to Buy and Sell Stock III Java Explanation Hard
☐ 124 Binary Tree Maximum Path Sum Java Explanation Hard
☐ 125 Valid Palindrome Java Explanation Easy
☐ 126 Word Ladder II Java Explanation Hard
☐ 127 Word Ladder Java Explanation Medium
☐ 128 Longest Consecutive Sequence Java Explanation Hard
☐ 129 Sum Root to Leaf Numbers Java Explanation Medium
☐ 130 Surrounded Regions Java Explanation Medium
☐ 131 Palindrome Partitioning Java Explanation Medium
☐ 132 Palindrome Partitioning II Java Explanation Hard
☐ 133 Clone Graph Java Explanation Medium
☐ 134 Gas Station Java Explanation Medium
☐ 135 Candy Java Explanation Hard
☐ 136 Single Number Java Explanation Easy
☐ 137 Single Number II Java Explanation Medium
☐ 138 Copy List with Random Pointer Java Explanation Medium
☐ 139 Word Break Java Explanation Medium
☐ 140 Word Break II Java Explanation Hard
☐ 141 Linked List Cycle Java Explanation Easy
☐ 142 Linked List Cycle II Java Explanation Medium
☐ 143 Reorder List Java Explanation Medium
☐ 144 Binary Tree Preorder Traversal Java Explanation Medium
☐ 145 Binary Tree Postorder Traversal Java Explanation Hard
☐ 146 LRU Cache Java Explanation Medium
☐ 147 Insertion Sort List Java Explanation Medium
☐ 148 Sort List Java Explanation Medium
☐ 149 Max Points on a Line Java Explanation Hard
☐ 150 Evaluate Reverse Polish Notation Java Explanation Medium
☐ 151 Reverse Words in a String Java Explanation Medium
☐ 152 Maximum Product Subarray Java Explanation Medium
☐ 153 Find Minimum in Rotated Sorted Array Java Explanation Medium
☐ 154 Find Minimum in Rotated Sorted Array II Java Explanation Hard
☐ 155 Min Stack Java Explanation Easy
☐ 156 Binary Tree Upside Down Java Explanation Medium
☐ 157 Read N Characters Given Read4 Java Explanation Easy
☐ 158 Read N Characters Given Read4 II - Call multiple times Java Explanation Hard
☐ 159 Longest Substring with At Most Two Distinct Characters Java Explanation Hard
☐ 160 Intersection of Two Linked Lists Java Explanation Easy
☐ 161 One Edit Distance Java Explanation Medium
☐ 162 Find Peak Element Java Explanation Medium
☐ 163 Missing Ranges Java Explanation Medium
☐ 164 Maximum Gap Java Explanation Hard
☐ 165 Compare Version Numbers Java Explanation Medium
☐ 166 Fraction to Recurring Decimal Java Explanation Medium
☐ 167 Two Sum II - Input array is sorted Java Explanation Easy
☐ 168 Excel Sheet Column Title Java Explanation Easy
☐ 169 Majority Element Java Explanation Easy
☐ 170 Two Sum III - Data structure design Java Explanation Easy
☐ 171 Excel Sheet Column Number Java Explanation Easy
☐ 172 Factorial Trailing Zeroes Java Explanation Easy
☐ 173 Binary Search Tree Iterator Java Explanation Medium
☐ 174 Dungeon Game Java Explanation Hard
☐ 179 Largest Number Java Explanation Medium
☐ 186 Reverse Words in a String II Java Explanation Medium
☐ 187 Repeated DNA Sequences Java Explanation Medium
☐ 188 Best Time to Buy and Sell Stock IV Java Explanation Hard
☐ 189 Rotate Array Java Explanation Easy
☐ 190 Reverse Bits Java Explanation Easy
☐ 191 Number of 1 Bits Java Explanation Easy
☐ 198 House Robber Java Explanation Easy
☐ 199 Binary Tree Right Side View Java Explanation Medium
☐ 200 Number of Islands Java Explanation Medium
☐ 201 Bitwise AND of Numbers Range Java Explanation Medium
☐ 202 Happy Number Java Explanation Easy
☐ 203 Remove Linked List Elements Java Explanation Easy
☐ 204 Count Primes Java Explanation Easy
☐ 205 Isomorphic Strings Java Explanation Easy
☐ 206 Reverse Linked List Java Explanation Easy
☑ 207 Course Schedule Java Explanation Medium
☐ 208 Implement Trie (Prefix Tree) Java Explanation Medium
☐ 209 Minimum Size Subarray Sum Java Explanation Medium
☑ 210 Course Schedule II Java Explanation Medium
☐ 211 Add and Search Word - Data structure design Java Explanation Medium
☐ 212 Word Search II Java Explanation Hard
☐ 213 House Robber II Java Explanation Medium
☐ 214 Shortest Palindrome Java Explanation Hard
☐ 215 Kth Largest Element in an Array Java Explanation Medium
☐ 216 Combination Sum III Java Explanation Medium
☐ 217 Contains Duplicate Java Explanation Easy
☐ 218 The Skyline Problem Java Explanation Hard
☐ 219 Contains Duplicate II Java Explanation Easy
☐ 220 Contains Duplicate III Java Explanation Medium
☐ 221 Maximal Square Java Explanation Medium
☐ 222 Count Complete Tree Nodes Java Explanation Medium
☐ 223 Rectangle Area Java Explanation Medium
☐ 224 Basic Calculator Java Explanation Hard
☐ 225 Implement Stack using Queues Java Explanation Easy
☐ 226 Invert Binary Tree Java Explanation Easy
☐ 227 Basic Calculator II Java Explanation Medium
☐ 228 Summary Ranges Java Explanation Medium
☐ 229 Majority Element II Java Explanation Medium
☐ 230 Kth Smallest Element in a BST Java Explanation Medium
☐ 231 Power of Two Java Explanation Easy
☐ 232 Implement Queue using Stacks Java Explanation Easy
☐ 233 Number of Digit One Java Explanation Hard
☐ 234 Palindrome Linked List Java Explanation Easy
☐ 235 Lowest Common Ancestor of a Binary Search Tree Java Explanation Easy
☐ 236 Lowest Common Ancestor of a Binary Tree Java Explanation Medium
☐ 237 Delete Node in a Linked List Java Explanation Easy
☐ 238 Product of Array Except Self Java Explanation Medium
☐ 239 Sliding Window Maximum Java Explanation Hard
☐ 240 Search a 2D Matrix II Java Explanation Medium
☐ 241 Different Ways to Add Parentheses Java Explanation Medium
☐ 242 Valid Anagram Java Explanation Easy
☐ 243 Shortest Word Distance Java Explanation Easy
☐ 244 Shortest Word Distance II Java Explanation Medium
☐ 245 Shortest Word Distance III Java Explanation Medium
☐ 246 Strobogrammatic Number Java Explanation Easy
☐ 247 Strobogrammatic Number II Java Explanation Medium
☐ 248 Strobogrammatic Number III Java Explanation Hard
☐ 249 Group Shifted Strings Java Explanation Medium
☐ 250 Count Univalue Subtrees Java Explanation Medium
☐ 251 Flatten 2D Vector Java Explanation Medium
☐ 252 Meeting Rooms Java Explanation Easy
☐ 253 Meeting Rooms II Java Explanation Medium
☐ 254 Factor Combinations Java Explanation Medium
☐ 255 Verify Preorder Sequence in Binary Search Tree Java Explanation Medium
☐ 256 Paint House Java Explanation Easy
☐ 257 Binary Tree Paths Java Explanation Easy
☐ 258 Add Digits Java Explanation Easy
☐ 259 3Sum Smaller Java Explanation Medium
☐ 260 Single Number III Java Explanation Medium
☐ 261 Graph Valid Tree Java Explanation Medium
☐ 263 Ugly Number Java Explanation Easy
☐ 264 Ugly Number II Java Explanation Medium
☐ 265 Paint House II Java Explanation Hard
☐ 266 Palindrome Permutation Java Explanation Easy
☐ 267 Palindrome Permutation II Java Explanation Medium
☐ 268 Missing Number Java Explanation Easy
☐ 269 Alien Dictionary Java Explanation Hard
☐ 270 Closest Binary Search Tree Value Java Explanation Easy
☐ 271 Encode and Decode Strings Java Explanation Medium
☐ 272 Closest Binary Search Tree Value II Java Explanation Hard
☐ 273 Integer to English Words Java Explanation Hard
☐ 274 H-Index Java Explanation Medium
☐ 275 H-Index II Java Explanation Medium
☐ 276 Paint Fence Java Explanation Easy
☐ 277 Find the Celebrity Java Explanation Medium
☐ 278 First Bad Version Java Explanation Easy
☐ 279 Perfect Squares Java Explanation Medium
☐ 280 Wiggle Sort Java Explanation Medium
☐ 281 Zigzag Iterator Java Explanation Medium
☐ 282 Expression Add Operators Java Explanation Hard
☐ 283 Move Zeroes Java Explanation Easy
☐ 284 Peeking Iterator Java Explanation Medium
☐ 285 Inorder Successor in BST Java Explanation Medium
☐ 286 Walls and Gates Java Explanation Medium
☐ 287 Find the Duplicate Number Java Explanation Medium
☐ 288 Unique Word Abbreviation Java Explanation Medium
☐ 289 Game of Life Java Explanation Medium
☐ 290 Word Pattern Java Explanation Easy
☐ 291 Word Pattern II Java Explanation Hard
☐ 292 Nim Game Java Explanation Easy
☐ 293 Flip Game Java Explanation Easy
☐ 294 Flip Game II Java Explanation Medium
☐ 295 Find Median from Data Stream Java Explanation Hard
☐ 296 Best Meeting Point Java Explanation Hard
☐ 297 Serialize and Deserialize Binary Tree Java Explanation Hard
☐ 298 Binary Tree Longest Consecutive Sequence Java Explanation Medium
☐ 299 Bulls and Cows Java Explanation Easy
☐ 300 Longest Increasing Subsequence Java Explanation Medium
☐ 301 Remove Invalid Parentheses Java Explanation Hard
☐ 302 Smallest Rectangle Enclosing Black Pixels Java Explanation Hard
☐ 303 Range Sum Query - Immutable Java Explanation Easy
☐ 304 Range Sum Query 2D - Immutable Java Explanation Medium
☐ 305 Number of Islands II Java Explanation Hard
☐ 306 Additive Number Java Explanation Medium
☐ 307 Range Sum Query - Mutable Java Explanation Medium
☐ 308 Range Sum Query 2D - Mutable Java Explanation Hard
☐ 309 Best Time to Buy and Sell Stock with Cooldown Java Explanation Medium
☐ 310 Minimum Height Trees Java Explanation Medium
☐ 311 Sparse Matrix Multiplication Java Explanation Medium
☐ 312 Burst Balloons Java Explanation Hard
☐ 313 Super Ugly Number Java Explanation Medium
☐ 314 Binary Tree Vertical Order Traversal Java Explanation Medium
☐ 315 Count of Smaller Numbers After Self Java Explanation Hard
☐ 316 Remove Duplicate Letters Java Explanation Hard
☐ 317 Shortest Distance from All Buildings Java Explanation Hard
☐ 318 Maximum Product of Word Lengths Java Explanation Medium
☐ 319 Bulb Switcher Java Explanation Medium
☐ 320 Generalized Abbreviation Java Explanation Medium
☐ 321 Create Maximum Number Java Explanation Hard
☐ 322 Coin Change Java Explanation Medium
☐ 323 Number of Connected Components in an Undirected Graph Java Explanation Medium
☐ 324 Wiggle Sort II Java Explanation Medium
☐ 325 Maximum Size Subarray Sum Equals k Java Explanation Medium
☐ 326 Power of Three Java Explanation Easy
☐ 327 Count of Range Sum Java Explanation Hard
☐ 328 Odd Even Linked List Java Explanation Medium
☐ 329 Longest Increasing Path in a Matrix Java Explanation Hard
☐ 330 Patching Array Java Explanation Hard
☐ 331 Verify Preorder Serialization of a Binary Tree Java Explanation Medium
☐ 332 Reconstruct Itinerary Java Explanation Medium
☐ 333 Largest BST Subtree Java Explanation Medium
☐ 334 Increasing Triplet Subsequence Java Explanation Medium
☐ 335 Self Crossing Java Explanation Hard
☐ 336 Palindrome Pairs Java Explanation Hard
☐ 337 House Robber III Java Explanation Medium
☐ 338 Counting Bits Java Explanation Medium
☐ 339 Nested List Weight Sum Java Explanation Easy
☐ 340 Longest Substring with At Most K Distinct Characters Java Explanation Hard
☐ 341 Flatten Nested List Iterator Java Explanation Medium
☐ 342 Power of Four Java Explanation Easy
☐ 343 Integer Break Java Explanation Medium
☐ 344 Reverse String Java Explanation Easy
☐ 345 Reverse Vowels of a String Java Explanation Easy
☐ 346 Moving Average from Data Stream Java Explanation Easy
☐ 347 Top K Frequent Elements Java Explanation Medium
☐ 348 Design Tic-Tac-Toe Java Explanation Medium
☐ 349 Intersection of Two Arrays Java Explanation Easy
☐ 350 Intersection of Two Arrays II Java Explanation Easy
☐ 351 Android Unlock Patterns Java Explanation Medium
☐ 352 Data Stream as Disjoint Intervals Java Explanation Hard
☐ 353 Design Snake Game Java Explanation Medium
☐ 354 Russian Doll Envelopes Java Explanation Hard
☐ 355 Design Twitter Java Explanation Medium
☐ 356 Line Reflection Java Explanation Medium
☐ 357 Count Numbers with Unique Digits Java Explanation Medium
☐ 358 Rearrange String k Distance Apart Java Explanation Hard
☐ 359 Logger Rate Limiter Java Explanation Easy
☐ 360 Sort Transformed Array Java Explanation Medium
☐ 361 Bomb Enemy Java Explanation Medium
☐ 362 Design Hit Counter Java Explanation Medium
☐ 363 Max Sum of Rectangle No Larger Than K Java Explanation Hard
☐ 364 Nested List Weight Sum II Java Explanation Medium
☐ 365 Water and Jug Problem Java Explanation Medium
☐ 366 Find Leaves of Binary Tree Java Explanation Medium
☐ 367 Valid Perfect Square Java Explanation Easy
☐ 368 Largest Divisible Subset Java Explanation Medium
☐ 369 Plus One Linked List Java Explanation Medium
☐ 370 Range Addition Java Explanation Medium
☐ 371 Sum of Two Integers Java Explanation Easy
☐ 372 Super Pow Java Explanation Medium
☐ 373 Find K Pairs with Smallest Sums Java Explanation Medium
☐ 374 Guess Number Higher or Lower Java Explanation Easy
☐ 375 Guess Number Higher or Lower II Java Explanation Medium
☐ 376 Wiggle Subsequence Java Explanation Medium
☐ 377 Combination Sum IV Java Explanation Medium
☐ 378 Kth Smallest Element in a Sorted Matrix Java Explanation Medium
☐ 379 Design Phone Directory Java Explanation Medium
☐ 380 Insert Delete GetRandom O(1) Java Explanation Medium
☐ 381 Insert Delete GetRandom O(1) - Duplicates allowed Java Explanation Hard
☐ 382 Linked List Random Node Java Explanation Medium
☐ 383 Ransom Note Java Explanation Easy
☐ 384 Shuffle an Array Java Explanation Medium
☐ 385 Mini Parser Java Explanation Medium
☐ 386 Lexicographical Numbers Java Explanation Medium
☐ 387 First Unique Character in a String Java Explanation Easy
☐ 388 Longest Absolute File Path Java Explanation Medium
☐ 389 Find the Difference Java Explanation Easy
☐ 390 Elimination Game Java Explanation Medium
☐ 391 Perfect Rectangle Java Explanation Hard
☐ 392 Is Subsequence Java Explanation Easy
☐ 393 UTF-8 Validation Java Explanation Medium
☐ 394 Decode String Java Explanation Medium
☐ 395 Longest Substring with At Least K Repeating Characters Java Explanation Medium
☐ 396 Rotate Function Java Explanation Medium
☐ 397 Integer Replacement Java Explanation Medium
☐ 398 Random Pick Index Java Explanation Medium
☐ 399 Evaluate Division Java Explanation Medium
☐ 400 Nth Digit Java Explanation Medium
☐ 401 Binary Watch Java Explanation Easy
☐ 402 Remove K Digits Java Explanation Medium
☐ 403 Frog Jump Java Explanation Hard
☐ 404 Sum of Left Leaves Java Explanation Easy
☐ 405 Convert a Number to Hexadecimal Java Explanation Easy
☐ 406 Queue Reconstruction by Height Java Explanation Medium
☐ 407 Trapping Rain Water II Java Explanation Hard
☐ 408 Valid Word Abbreviation Java Explanation Easy
☐ 409 Longest Palindrome Java Explanation Easy
☐ 410 Split Array Largest Sum Java Explanation Hard
☐ 411 Minimum Unique Word Abbreviation Java Explanation Hard
☐ 412 Fizz Buzz Java Explanation Easy
☐ 413 Arithmetic Slices Java Explanation Medium
☐ 414 Third Maximum Number Java Explanation Easy
☐ 415 Add Strings Java Explanation Easy
☐ 416 Partition Equal Subset Sum Java Explanation Medium
☐ 417 Pacific Atlantic Water Flow Java Explanation Medium
☐ 418 Sentence Screen Fitting Java Explanation Medium
☐ 419 Battleships in a Board Java Explanation Medium
☐ 420 Strong Password Checker Java Explanation Hard
☐ 421 Maximum XOR of Two Numbers in an Array Java Explanation Medium
☐ 422 Valid Word Square Java Explanation Easy
☐ 423 Reconstruct Original Digits from English Java Explanation Medium
☐ 424 Longest Repeating Character Replacement Java Explanation Medium
☐ 425 Word Squares Java Explanation Hard
☐ 426 Convert Binary Search Tree to Sorted Doubly Linked List Java Explanation Medium
☐ 427 Construct Quad Tree Java Explanation Medium
☐ 428 Serialize and Deserialize N-ary Tree Java Explanation Hard
☐ 429 N-ary Tree Level Order Traversal Java Explanation Easy
☐ 430 Flatten a Multilevel Doubly Linked List Java Explanation Medium
☐ 431 Encode N-ary Tree to Binary Tree Java Explanation Hard
☐ 432 All O`one Data Structure Java Explanation Hard
☐ 433 Minimum Genetic Mutation Java Explanation Medium
☐ 434 Number of Segments in a String Java Explanation Easy
☐ 435 Non-overlapping Intervals Java Explanation Medium
☐ 436 Find Right Interval Java Explanation Medium
☐ 437 Path Sum III Java Explanation Easy
☐ 438 Find All Anagrams in a String Java Explanation Medium
☐ 439 Ternary Expression Parser Java Explanation Medium
☐ 440 K-th Smallest in Lexicographical Order Java Explanation Hard
☐ 441 Arranging Coins Java Explanation Easy
☐ 442 Find All Duplicates in an Array Java Explanation Medium
☐ 443 String Compression Java Explanation Easy
☐ 444 Sequence Reconstruction Java Explanation Medium
☐ 445 Add Two Numbers II Java Explanation Medium
☐ 446 Arithmetic Slices II - Subsequence Java Explanation Hard
☐ 447 Number of Boomerangs Java Explanation Easy
☐ 448 Find All Numbers Disappeared in an Array Java Explanation Easy
☐ 449 Serialize and Deserialize BST Java Explanation Medium
☐ 450 Delete Node in a BST Java Explanation Medium
☐ 451 Sort Characters By Frequency Java Explanation Medium
☐ 452 Minimum Number of Arrows to Burst Balloons Java Explanation Medium
☐ 453 Minimum Moves to Equal Array Elements Java Explanation Easy
☐ 454 4Sum II Java Explanation Medium
☐ 455 Assign Cookies Java Explanation Easy
☐ 456 132 Pattern Java Explanation Medium
☐ 457 Circular Array Loop Java Explanation Medium
☐ 458 Poor Pigs Java Explanation Hard
☐ 459 Repeated Substring Pattern Java Explanation Easy
☐ 460 LFU Cache Java Explanation Hard
☐ 461 Hamming Distance Java Explanation Easy
☐ 462 Minimum Moves to Equal Array Elements II Java Explanation Medium
☐ 463 Island Perimeter Java Explanation Easy
☐ 464 Can I Win Java Explanation Medium
☐ 465 Optimal Account Balancing Java Explanation Hard
☐ 466 Count The Repetitions Java Explanation Hard
☐ 467 Unique Substrings in Wraparound String Java Explanation Medium
☐ 468 Validate IP Address Java Explanation Medium
☐ 469 Convex Polygon Java Explanation Medium
☐ 470 Implement Rand10() Using Rand7() Java Explanation Medium
☐ 471 Encode String with Shortest Length Java Explanation Hard
☐ 472 Concatenated Words Java Explanation Hard
☐ 473 Matchsticks to Square Java Explanation Medium
☐ 474 Ones and Zeroes Java Explanation Medium
☐ 475 Heaters Java Explanation Easy
☐ 476 Number Complement Java Explanation Easy
☐ 477 Total Hamming Distance Java Explanation Medium
☐ 478 Generate Random Point in a Circle Java Explanation Medium
☐ 479 Largest Palindrome Product Java Explanation Hard
☐ 480 Sliding Window Median Java Explanation Hard
☐ 481 Magical String Java Explanation Medium
☐ 482 License Key Formatting Java Explanation Easy
☐ 483 Smallest Good Base Java Explanation Hard
☐ 484 Find Permutation Java Explanation Medium
☐ 485 Max Consecutive Ones Java Explanation Easy
☐ 486 Predict the Winner Java Explanation Medium
☐ 487 Max Consecutive Ones II Java Explanation Medium
☐ 488 Zuma Game Java Explanation Hard
☐ 489 Robot Room Cleaner Java Explanation Hard
☐ 490 The Maze Java Explanation Medium
☐ 491 Increasing Subsequences Java Explanation Medium
☐ 492 Construct the Rectangle Java Explanation Easy
☐ 493 Reverse Pairs Java Explanation Hard
☐ 494 Target Sum Java Explanation Medium
☐ 495 Teemo Attacking Java Explanation Medium
☐ 496 Next Greater Element I Java Explanation Easy
☐ 497 Random Point in Non-overlapping Rectangles Java Explanation Medium
☐ 498 Diagonal Traverse Java Explanation Medium
☐ 499 The Maze III Java Explanation Hard
☐ 500 Keyboard Row Java Explanation Easy
☐ 501 Find Mode in Binary Search Tree Java Explanation Easy
☐ 502 IPO Java Explanation Hard
☐ 503 Next Greater Element II Java Explanation Medium
☐ 504 Base 7 Java Explanation Easy
☐ 505 The Maze II Java Explanation Medium
☐ 506 Relative Ranks Java Explanation Easy
☐ 507 Perfect Number Java Explanation Easy
☐ 508 Most Frequent Subtree Sum Java Explanation Medium
☐ 509 Fibonacci Number Java Explanation Easy
☐ 510 Inorder Successor in BST II Java Explanation Medium
☐ 513 Find Bottom Left Tree Value Java Explanation Medium
☐ 514 Freedom Trail Java Explanation Hard
☐ 515 Find Largest Value in Each Tree Row Java Explanation Medium
☐ 516 Longest Palindromic Subsequence Java Explanation Medium
☐ 517 Super Washing Machines Java Explanation Hard
☐ 518 Coin Change 2 Java Explanation Medium
☐ 519 Random Flip Matrix Java Explanation Medium
☐ 520 Detect Capital Java Explanation Easy
☐ 521 Longest Uncommon Subsequence I Java Explanation Easy
☐ 522 Longest Uncommon Subsequence II Java Explanation Medium
☐ 523 Continuous Subarray Sum Java Explanation Medium
☐ 524 Longest Word in Dictionary through Deleting Java Explanation Medium
☐ 525 Contiguous Array Java Explanation Medium
☐ 526 Beautiful Arrangement Java Explanation Medium
☐ 527 Word Abbreviation Java Explanation Hard
☐ 528 Random Pick with Weight Java Explanation Medium
☐ 529 Minesweeper Java Explanation Medium
☐ 530 Minimum Absolute Difference in BST Java Explanation Easy
☐ 531 Lonely Pixel I Java Explanation Medium
☐ 532 K-diff Pairs in an Array Java Explanation Easy
☐ 533 Lonely Pixel II Java Explanation Medium
☐ 535 Encode and Decode TinyURL Java Explanation Medium
☐ 536 Construct Binary Tree from String Java Explanation Medium
☐ 537 Complex Number Multiplication Java Explanation Medium
☐ 538 Convert BST to Greater Tree Java Explanation Easy
☐ 539 Minimum Time Difference Java Explanation Medium
☐ 540 Single Element in a Sorted Array Java Explanation Medium
☐ 541 Reverse String II Java Explanation Easy
☐ 542 01 Matrix Java Explanation Medium
☐ 543 Diameter of Binary Tree Java Explanation Easy
☐ 544 Output Contest Matches Java Explanation Medium
☐ 545 Boundary of Binary Tree Java Explanation Medium
☐ 546 Remove Boxes Java Explanation Hard
☐ 547 Friend Circles Java Explanation Medium
☐ 548 Split Array with Equal Sum Java Explanation Medium
☐ 549 Binary Tree Longest Consecutive Sequence II Java Explanation Medium
☐ 551 Student Attendance Record I Java Explanation Easy
☐ 552 Student Attendance Record II Java Explanation Hard
☐ 553 Optimal Division Java Explanation Medium
☐ 554 Brick Wall Java Explanation Medium
☐ 555 Split Concatenated Strings Java Explanation Medium
☐ 556 Next Greater Element III Java Explanation Medium
☐ 557 Reverse Words in a String III Java Explanation Easy
☐ 558 Quad Tree Intersection Java Explanation Easy
☐ 559 Maximum Depth of N-ary Tree Java Explanation Easy
☐ 560 Subarray Sum Equals K Java Explanation Medium
☐ 561 Array Partition I Java Explanation Easy
☐ 562 Longest Line of Consecutive One in Matrix Java Explanation Medium
☐ 563 Binary Tree Tilt Java Explanation Easy
☐ 564 Find the Closest Palindrome Java Explanation Hard
☐ 565 Array Nesting Java Explanation Medium
☐ 566 Reshape the Matrix Java Explanation Easy
☐ 567 Permutation in String Java Explanation Medium
☐ 568 Maximum Vacation Days Java Explanation Hard
☑ 572 Subtree of Another Tree Java Explanation Easy
☐ 573 Squirrel Simulation Java Explanation Medium
☐ 575 Distribute Candies Java Explanation Easy
☐ 576 Out of Boundary Paths Java Explanation Medium
☐ 581 Shortest Unsorted Continuous Subarray Java Explanation Easy
☐ 582 Kill Process Java Explanation Medium
☐ 583 Delete Operation for Two Strings Java Explanation Medium
☐ 587 Erect the Fence Java Explanation Hard
☐ 588 Design In-Memory File System Java Explanation Hard
☐ 589 N-ary Tree Preorder Traversal Java Explanation Easy
☐ 590 N-ary Tree Postorder Traversal Java Explanation Easy
☐ 591 Tag Validator Java Explanation Hard
☐ 592 Fraction Addition and Subtraction Java Explanation Medium
☐ 593 Valid Square Java Explanation Medium
☐ 594 Longest Harmonious Subsequence Java Explanation Easy
☐ 598 Range Addition II Java Explanation Easy
☐ 599 Minimum Index Sum of Two Lists Java Explanation Easy
☐ 600 Non-negative Integers without Consecutive Ones Java Explanation Hard
☐ 604 Design Compressed String Iterator Java Explanation Easy
☐ 605 Can Place Flowers Java Explanation Easy
☐ 606 Construct String from Binary Tree Java Explanation Easy
☐ 609 Find Duplicate File in System Java Explanation Medium
☐ 611 Valid Triangle Number Java Explanation Medium
☐ 616 Add Bold Tag in String Java Explanation Medium
☐ 617 Merge Two Binary Trees Java Explanation Easy
☐ 621 Task Scheduler Java Explanation Medium
☐ 622 Design Circular Queue Java Explanation Medium
☐ 623 Add One Row to Tree Java Explanation Medium
☐ 624 Maximum Distance in Arrays Java Explanation Easy
☐ 625 Minimum Factorization Java Explanation Medium
☐ 628 Maximum Product of Three Numbers Java Explanation Easy
☐ 629 K Inverse Pairs Array Java Explanation Hard
☐ 630 Course Schedule III Java Explanation Hard
☐ 631 Design Excel Sum Formula Java Explanation Hard
☐ 632 Smallest Range Covering Elements from K Lists Java Explanation Hard
☐ 633 Sum of Square Numbers Java Explanation Easy
☐ 634 Find the Derangement of An Array Java Explanation Medium
☐ 635 Design Log Storage System Java Explanation Medium
☐ 636 Exclusive Time of Functions Java Explanation Medium
☐ 637 Average of Levels in Binary Tree Java Explanation Easy
☐ 638 Shopping Offers Java Explanation Medium
☐ 639 Decode Ways II Java Explanation Hard
☐ 640 Solve the Equation Java Explanation Medium
☐ 641 Design Circular Deque Java Explanation Medium
☐ 642 Design Search Autocomplete System Java Explanation Hard
☐ 643 Maximum Average Subarray I Java Explanation Easy
☐ 644 Maximum Average Subarray II Java Explanation Hard
☐ 645 Set Mismatch Java Explanation Easy
☐ 646 Maximum Length of Pair Chain Java Explanation Medium
☐ 647 Palindromic Substrings Java Explanation Medium
☐ 648 Replace Words Java Explanation Medium
☐ 649 Dota2 Senate Java Explanation Medium
☐ 650 2 Keys Keyboard Java Explanation Medium
☐ 651 4 Keys Keyboard Java Explanation Medium
☐ 652 Find Duplicate Subtrees Java Explanation Medium
☐ 653 Two Sum IV - Input is a BST Java Explanation Easy
☐ 654 Maximum Binary Tree Java Explanation Medium
☐ 655 Print Binary Tree Java Explanation Medium
☐ 656 Coin Path Java Explanation Hard
☐ 657 Robot Return to Origin Java Explanation Easy
☐ 658 Find K Closest Elements Java Explanation Medium
☐ 659 Split Array into Consecutive Subsequences Java Explanation Medium
☐ 660 Remove 9 Java Explanation Hard
☐ 661 Image Smoother Java Explanation Easy
☐ 662 Maximum Width of Binary Tree Java Explanation Medium
☐ 663 Equal Tree Partition Java Explanation Medium
☐ 664 Strange Printer Java Explanation Hard
☐ 665 Non-decreasing Array Java Explanation Easy
☐ 666 Path Sum IV Java Explanation Medium
☐ 667 Beautiful Arrangement II Java Explanation Medium
☐ 668 Kth Smallest Number in Multiplication Table Java Explanation Hard
☐ 669 Trim a Binary Search Tree Java Explanation Easy
☐ 670 Maximum Swap Java Explanation Medium
☐ 671 Second Minimum Node In a Binary Tree Java Explanation Easy
☐ 672 Bulb Switcher II Java Explanation Medium
☐ 673 Number of Longest Increasing Subsequence Java Explanation Medium
☐ 674 Longest Continuous Increasing Subsequence Java Explanation Easy
☐ 675 Cut Off Trees for Golf Event Java Explanation Hard
☐ 676 Implement Magic Dictionary Java Explanation Medium
☐ 677 Map Sum Pairs Java Explanation Medium
☐ 678 Valid Parenthesis String Java Explanation Medium
☐ 679 24 Game Java Explanation Hard
☐ 680 Valid Palindrome II Java Explanation Easy
☐ 681 Next Closest Time Java Explanation Medium
☐ 682 Baseball Game Java Explanation Easy
☐ 683 K Empty Slots Java Explanation Hard
☐ 684 Redundant Connection Java Explanation Medium
☐ 685 Redundant Connection II Java Explanation Hard
☐ 686 Repeated String Match Java Explanation Easy
☐ 687 Longest Univalue Path Java Explanation Easy
☐ 688 Knight Probability in Chessboard Java Explanation Medium
☐ 689 Maximum Sum of 3 Non-Overlapping Subarrays Java Explanation Hard
☐ 690 Employee Importance Java Explanation Easy
☐ 691 Stickers to Spell Word Java Explanation Hard
☐ 692 Top K Frequent Words Java Explanation Medium
☐ 693 Binary Number with Alternating Bits Java Explanation Easy
☐ 694 Number of Distinct Islands Java Explanation Medium
☐ 695 Max Area of Island Java Explanation Medium
☐ 696 Count Binary Substrings Java Explanation Easy
☐ 697 Degree of an Array Java Explanation Easy
☐ 698 Partition to K Equal Sum Subsets Java Explanation Medium
☐ 699 Falling Squares Java Explanation Hard
☐ 700 Search in a Binary Search Tree Java Explanation Easy
☐ 701 Insert into a Binary Search Tree Java Explanation Medium
☐ 702 Search in a Sorted Array of Unknown Size Java Explanation Medium
☐ 703 Kth Largest Element in a Stream Java Explanation Easy
☐ 704 Binary Search Java Explanation Easy
☐ 705 Design HashSet Java Explanation Easy
☐ 706 Design HashMap Java Explanation Easy
☐ 707 Design Linked List Java Explanation Easy
☐ 708 Insert into a Cyclic Sorted List Java Explanation Medium
☐ 709 To Lower Case Java Explanation Easy
☐ 710 Random Pick with Blacklist Java Explanation Hard
☐ 711 Number of Distinct Islands II Java Explanation Hard
☐ 712 Minimum ASCII Delete Sum for Two Strings Java Explanation Medium
☐ 713 Subarray Product Less Than K Java Explanation Medium
☐ 714 Best Time to Buy and Sell Stock with Transaction Fee Java Explanation Medium
☐ 715 Range Module Java Explanation Hard
☐ 716 Max Stack Java Explanation Easy
☐ 717 1-bit and 2-bit Characters Java Explanation Easy
☐ 718 Maximum Length of Repeated Subarray Java Explanation Medium
☐ 719 Find K-th Smallest Pair Distance Java Explanation Hard
☐ 720 Longest Word in Dictionary Java Explanation Easy
☐ 721 Accounts Merge Java Explanation Medium
☐ 722 Remove Comments Java Explanation Medium
☐ 723 Candy Crush Java Explanation Medium
☐ 724 Find Pivot Index Java Explanation Easy
☐ 725 Split Linked List in Parts Java Explanation Medium
☐ 726 Number of Atoms Java Explanation Hard
☐ 727 Minimum Window Subsequence Java Explanation Hard
☐ 728 Self Dividing Numbers Java Explanation Easy
☐ 729 My Calendar I Java Explanation Medium
☐ 730 Count Different Palindromic Subsequences Java Explanation Hard
☐ 731 My Calendar II Java Explanation Medium
☐ 732 My Calendar III Java Explanation Hard
☐ 733 Flood Fill Java Explanation Easy
☐ 734 Sentence Similarity Java Explanation Easy
☐ 735 Asteroid Collision Java Explanation Medium
☐ 736 Parse Lisp Expression Java Explanation Hard
☐ 737 Sentence Similarity II Java Explanation Medium
☐ 738 Monotone Increasing Digits Java Explanation Medium
☐ 739 Daily Temperatures Java Explanation Medium
☐ 740 Delete and Earn Java Explanation Medium
☐ 741 Cherry Pickup Java Explanation Hard
☐ 742 Closest Leaf in a Binary Tree Java Explanation Medium
☐ 743 Network Delay Time Java Explanation Medium
☐ 744 Find Smallest Letter Greater Than Target Java Explanation Easy
☐ 745 Prefix and Suffix Search Java Explanation Hard
☐ 746 Min Cost Climbing Stairs Java Explanation Easy
☐ 747 Largest Number At Least Twice of Others Java Explanation Easy
☐ 748 Shortest Completing Word Java Explanation Easy
☐ 749 Contain Virus Java Explanation Hard
☐ 750 Number Of Corner Rectangles Java Explanation Medium
☐ 751 IP to CIDR Java Explanation Easy
☐ 752 Open the Lock Java Explanation Medium
☐ 753 Cracking the Safe Java Explanation Hard
☐ 754 Reach a Number Java Explanation Easy
☐ 755 Pour Water Java Explanation Medium
☐ 756 Pyramid Transition Matrix Java Explanation Medium
☐ 757 Set Intersection Size At Least Two Java Explanation Hard
☐ 758 Bold Words in String Java Explanation Easy
☐ 759 Employee Free Time Java Explanation Hard
☐ 760 Find Anagram Mappings Java Explanation Easy
☐ 761 Special Binary String Java Explanation Hard
☐ 762 Prime Number of Set Bits in Binary Representation Java Explanation Easy
☐ 763 Partition Labels Java Explanation Medium
☐ 764 Largest Plus Sign Java Explanation Medium
☐ 765 Couples Holding Hands Java Explanation Hard
☐ 766 Toeplitz Matrix Java Explanation Easy
☐ 767 Reorganize String Java Explanation Medium
☐ 768 Max Chunks To Make Sorted II Java Explanation Hard
☐ 769 Max Chunks To Make Sorted Java Explanation Medium
☐ 770 Basic Calculator IV Java Explanation Hard
☐ 771 Jewels and Stones Java Explanation Easy
☐ 772 Basic Calculator III Java Explanation Hard
☐ 773 Sliding Puzzle Java Explanation Hard
☐ 774 Minimize Max Distance to Gas Station Java Explanation Hard
☐ 775 Global and Local Inversions Java Explanation Medium
☐ 776 Split BST Java Explanation Medium
☐ 777 Swap Adjacent in LR String Java Explanation Medium
☐ 778 Swim in Rising Water Java Explanation Hard
☐ 779 K-th Symbol in Grammar Java Explanation Medium
☐ 780 Reaching Points Java Explanation Hard
☐ 781 Rabbits in Forest Java Explanation Medium
☐ 782 Transform to Chessboard Java Explanation Hard
☐ 783 Minimum Distance Between BST Nodes Java Explanation Easy
☐ 784 Letter Case Permutation Java Explanation Easy
☐ 785 Is Graph Bipartite? Java Explanation Medium
☐ 786 K-th Smallest Prime Fraction Java Explanation Hard
☐ 787 Cheapest Flights Within K Stops Java Explanation Medium
☐ 788 Rotated Digits Java Explanation Easy
☐ 789 Escape The Ghosts Java Explanation Medium
☐ 790 Domino and Tromino Tiling Java Explanation Medium
☐ 791 Custom Sort String Java Explanation Medium
☐ 792 Number of Matching Subsequences Java Explanation Medium
☐ 793 Preimage Size of Factorial Zeroes Function Java Explanation Hard
☐ 794 Valid Tic-Tac-Toe State Java Explanation Medium
☐ 795 Number of Subarrays with Bounded Maximum Java Explanation Medium
☐ 796 Rotate String Java Explanation Easy
☐ 797 All Paths From Source to Target Java Explanation Medium
☐ 798 Smallest Rotation with Highest Score Java Explanation Hard
☐ 799 Champagne Tower Java Explanation Medium
☐ 800 Similar RGB Color Java Explanation Easy
☐ 801 Minimum Swaps To Make Sequences Increasing Java Explanation Medium
☐ 802 Find Eventual Safe States Java Explanation Medium
☐ 803 Bricks Falling When Hit Java Explanation Hard
☐ 804 Unique Morse Code Words Java Explanation Easy
☐ 805 Split Array With Same Average Java Explanation Hard
☐ 806 Number of Lines To Write String Java Explanation Easy
☐ 807 Max Increase to Keep City Skyline Java Explanation Medium
☐ 808 Soup Servings Java Explanation Medium
☐ 809 Expressive Words Java Explanation Medium
☐ 810 Chalkboard XOR Game Java Explanation Hard
☐ 811 Subdomain Visit Count Java Explanation Easy
☐ 812 Largest Triangle Area Java Explanation Easy
☐ 813 Largest Sum of Averages Java Explanation Medium
☐ 814 Binary Tree Pruning Java Explanation Medium
☐ 815 Bus Routes Java Explanation Hard
☐ 816 Ambiguous Coordinates Java Explanation Medium
☐ 817 Linked List Components Java Explanation Medium
☐ 818 Race Car Java Explanation Hard
☐ 819 Most Common Word Java Explanation Easy
☐ 820 Short Encoding of Words Java Explanation Medium
☐ 821 Shortest Distance to a Character Java Explanation Easy
☐ 822 Card Flipping Game Java Explanation Medium
☐ 823 Binary Trees With Factors Java Explanation Medium
☐ 824 Goat Latin Java Explanation Easy
☐ 825 Friends Of Appropriate Ages Java Explanation Medium
☐ 826 Most Profit Assigning Work Java Explanation Medium
☐ 827 Making A Large Island Java Explanation Hard
☐ 828 Unique Letter String Java Explanation Hard
☐ 829 Consecutive Numbers Sum Java Explanation Hard
☐ 830 Positions of Large Groups Java Explanation Easy
☐ 831 Masking Personal Information Java Explanation Medium
☐ 832 Flipping an Image Java Explanation Easy
☐ 833 Find And Replace in String Java Explanation Medium
☐ 834 Sum of Distances in Tree Java Explanation Hard
☐ 835 Image Overlap Java Explanation Medium
☐ 836 Rectangle Overlap Java Explanation Easy
☐ 837 New 21 Game Java Explanation Medium
☐ 838 Push Dominoes Java Explanation Medium
☐ 839 Similar String Groups Java Explanation Hard
☐ 840 Magic Squares In Grid Java Explanation Easy
☐ 841 Keys and Rooms Java Explanation Medium
☐ 842 Split Array into Fibonacci Sequence Java Explanation Medium
☐ 843 Guess the Word Java Explanation Hard
☐ 844 Backspace String Compare Java Explanation Easy
☐ 845 Longest Mountain in Array Java Explanation Medium
☐ 846 Hand of Straights Java Explanation Medium
☐ 847 Shortest Path Visiting All Nodes Java Explanation Hard
☐ 848 Shifting Letters Java Explanation Medium
☐ 849 Maximize Distance to Closest Person Java Explanation Easy
☐ 850 Rectangle Area II Java Explanation Hard
☐ 851 Loud and Rich Java Explanation Medium
☐ 852 Peak Index in a Mountain Array Java Explanation Easy
☐ 853 Car Fleet Java Explanation Medium
☐ 854 K-Similar Strings Java Explanation Hard
☐ 855 Exam Room Java Explanation Medium
☐ 856 Score of Parentheses Java Explanation Medium
☐ 857 Minimum Cost to Hire K Workers Java Explanation Hard
☐ 858 Mirror Reflection Java Explanation Medium
☐ 859 Buddy Strings Java Explanation Easy
☐ 860 Lemonade Change Java Explanation Easy
☐ 861 Score After Flipping Matrix Java Explanation Medium
☐ 862 Shortest Subarray with Sum at Least K Java Explanation Hard
☐ 863 All Nodes Distance K in Binary Tree Java Explanation Medium
☐ 864 Shortest Path to Get All Keys Java Explanation Hard
☐ 865 Smallest Subtree with all the Deepest Nodes Java Explanation Medium
☐ 866 Prime Palindrome Java Explanation Medium
☐ 867 Transpose Matrix Java Explanation Easy
☐ 868 Binary Gap Java Explanation Easy
☐ 869 Reordered Power of 2 Java Explanation Medium
☐ 870 Advantage Shuffle Java Explanation Medium
☐ 871 Minimum Number of Refueling Stops Java Explanation Hard
☐ 872 Leaf-Similar Trees Java Explanation Easy
☐ 873 Length of Longest Fibonacci Subsequence Java Explanation Medium
☐ 874 Walking Robot Simulation Java Explanation Easy
☐ 875 Koko Eating Bananas Java Explanation Medium
☐ 876 Middle of the Linked List Java Explanation Easy
☐ 877 Stone Game Java Explanation Medium
☐ 878 Nth Magical Number Java Explanation Hard
☐ 879 Profitable Schemes Java Explanation Hard
☐ 880 Decoded String at Index Java Explanation Medium
☐ 881 Boats to Save People Java Explanation Medium
☐ 882 Reachable Nodes In Subdivided Graph Java Explanation Hard
☐ 883 Projection Area of 3D Shapes Java Explanation Easy
☐ 884 Uncommon Words from Two Sentences Java Explanation Easy
☐ 885 Spiral Matrix III Java Explanation Medium
☐ 886 Possible Bipartition Java Explanation Medium
☐ 887 Super Egg Drop Java Explanation Hard
☐ 888 Fair Candy Swap Java Explanation Easy
☐ 889 Construct Binary Tree from Preorder and Postorder Traversal Java Explanation Medium
☐ 890 Find and Replace Pattern Java Explanation Medium
☐ 891 Sum of Subsequence Widths Java Explanation Hard
☐ 892 Surface Area of 3D Shapes Java Explanation Easy
☐ 893 Groups of Special-Equivalent Strings Java Explanation Easy
☐ 894 All Possible Full Binary Trees Java Explanation Medium
☐ 895 Maximum Frequency Stack Java Explanation Hard
☐ 896 Monotonic Array Java Explanation Easy
☐ 897 Increasing Order Search Tree Java Explanation Easy
☐ 898 Bitwise ORs of Subarrays Java Explanation Medium
☐ 899 Orderly Queue Java Explanation Hard
☐ 900 RLE Iterator Java Explanation Medium
☐ 901 Online Stock Span Java Explanation Medium
☐ 902 Numbers At Most N Given Digit Set Java Explanation Hard
☐ 903 Valid Permutations for DI Sequence Java Explanation Hard
☐ 904 Fruit Into Baskets Java Explanation Medium
☐ 905 Sort Array By Parity Java Explanation Easy
☐ 906 Super Palindromes Java Explanation Hard
☐ 907 Sum of Subarray Minimums Java Explanation Medium
☐ 908 Smallest Range I Java Explanation Easy
☐ 909 Snakes and Ladders Java Explanation Medium
☐ 910 Smallest Range II Java Explanation Medium
☐ 911 Online Election Java Explanation Medium
☐ 912 Sort an Array Java Explanation Medium
☐ 913 Cat and Mouse Java Explanation Hard
☐ 914 X of a Kind in a Deck of Cards Java Explanation Easy
☐ 915 Partition Array into Disjoint Intervals Java Explanation Medium
☐ 916 Word Subsets Java Explanation Medium
☐ 917 Reverse Only Letters Java Explanation Easy
☐ 918 Maximum Sum Circular Subarray Java Explanation Medium
☐ 919 Complete Binary Tree Inserter Java Explanation Medium
☐ 920 Number of Music Playlists Java Explanation Hard
☐ 921 Minimum Add to Make Parentheses Valid Java Explanation Medium
☐ 922 Sort Array By Parity II Java Explanation Easy
☐ 923 3Sum With Multiplicity Java Explanation Medium
☐ 924 Minimize Malware Spread Java Explanation Hard
☐ 925 Long Pressed Name Java Explanation Easy
☐ 926 Flip String to Monotone Increasing Java Explanation Medium
☐ 927 Three Equal Parts Java Explanation Hard
☐ 928 Minimize Malware Spread II Java Explanation Hard
☐ 929 Unique Email Addresses Java Explanation Easy
☐ 930 Binary Subarrays With Sum Java Explanation Medium
☐ 931 Minimum Falling Path Sum Java Explanation Medium
☐ 932 Beautiful Array Java Explanation Medium
☐ 933 Number of Recent Calls Java Explanation Easy
☐ 934 Shortest Bridge Java Explanation Medium
☐ 935 Knight Dialer Java Explanation Medium
☐ 936 Stamping The Sequence Java Explanation Hard
☐ 937 Reorder Data in Log Files Java Explanation Easy
☐ 938 Range Sum of BST Java Explanation Easy
☐ 939 Minimum Area Rectangle Java Explanation Medium
☐ 940 Distinct Subsequences II Java Explanation Hard
☐ 941 Valid Mountain Array Java Explanation Easy
☐ 942 DI String Match Java Explanation Easy
☐ 943 Find the Shortest Superstring Java Explanation Hard
☐ 944 Delete Columns to Make Sorted Java Explanation Easy
☐ 945 Minimum Increment to Make Array Unique Java Explanation Medium
☐ 946 Validate Stack Sequences Java Explanation Medium
☐ 947 Most Stones Removed with Same Row or Column Java Explanation Medium
☐ 948 Bag of Tokens Java Explanation Medium
☐ 949 Largest Time for Given Digits Java Explanation Easy
☐ 950 Reveal Cards In Increasing Order Java Explanation Medium
☐ 951 Flip Equivalent Binary Trees Java Explanation Medium
☐ 952 Largest Component Size by Common Factor Java Explanation Hard
☐ 953 Verifying an Alien Dictionary Java Explanation Easy
☐ 954 Array of Doubled Pairs Java Explanation Medium
☐ 955 Delete Columns to Make Sorted II Java Explanation Medium
☐ 956 Tallest Billboard Java Explanation Hard
☐ 957 Prison Cells After N Days Java Explanation Medium
☐ 958 Check Completeness of a Binary Tree Java Explanation Medium
☐ 959 Regions Cut By Slashes Java Explanation Medium
☐ 960 Delete Columns to Make Sorted III Java Explanation Hard
☐ 961 N-Repeated Element in Size 2N Array Java Explanation Easy
☐ 962 Maximum Width Ramp Java Explanation Medium
☐ 963 Minimum Area Rectangle II Java Explanation Medium
☐ 964 Least Operators to Express Number Java Explanation Hard
☐ 965 Univalued Binary Tree Java Explanation Easy
☐ 966 Vowel Spellchecker Java Explanation Medium
☐ 967 Numbers With Same Consecutive Differences Java Explanation Medium
☐ 968 Binary Tree Cameras Java Explanation Hard
☐ 969 Pancake Sorting Java Explanation Medium
☐ 970 Powerful Integers Java Explanation Easy
☐ 971 Flip Binary Tree To Match Preorder Traversal Java Explanation Medium
☐ 972 Equal Rational Numbers Java Explanation Hard
☐ 973 K Closest Points to Origin Java Explanation Medium
☐ 974 Subarray Sums Divisible by K Java Explanation Medium
☐ 975 Odd Even Jump Java Explanation Hard
☐ 976 Largest Perimeter Triangle Java Explanation Easy
☐ 977 Squares of a Sorted Array Java Explanation Easy
☐ 978 Longest Turbulent Subarray Java Explanation Medium
☐ 979 Distribute Coins in Binary Tree Java Explanation Medium
☐ 980 Unique Paths III Java Explanation Hard
☐ 981 Time Based Key-Value Store Java Explanation Medium
☐ 982 Triples with Bitwise AND Equal To Zero Java Explanation Hard
☐ 983 Minimum Cost For Tickets Java Explanation Medium
☐ 984 String Without AAA or BBB Java Explanation Medium
☐ 985 Sum of Even Numbers After Queries Java Explanation Easy
☐ 986 Interval List Intersections Java Explanation Medium
☐ 987 Vertical Order Traversal of a Binary Tree Java Explanation Medium
☐ 988 Smallest String Starting From Leaf Java Explanation Medium
☐ 989 Add to Array-Form of Integer Java Explanation Easy
☐ 990 Satisfiability of Equality Equations Java Explanation Medium
☐ 991 Broken Calculator Java Explanation Medium
☐ 992 Subarrays with K Different Integers Java Explanation Hard
☐ 993 Cousins in Binary Tree Java Explanation Easy
☐ 994 Rotting Oranges Java Explanation Easy
☐ 995 Minimum Number of K Consecutive Bit Flips Java Explanation Hard
☐ 996 Number of Squareful Arrays Java Explanation Hard
☐ 997 Find the Town Judge Java Explanation Easy
☐ 998 Maximum Binary Tree II Java Explanation Medium
☐ 999 Available Captures for Rook Java Explanation Easy
☐ 1000 Minimum Cost to Merge Stones Java Explanation Hard
☐ 1001 Grid Illumination Java Explanation Hard
☐ 1002 Find Common Characters Java Explanation Easy
☐ 1003 Check If Word Is Valid After Substitutions Java Explanation Medium
☐ 1004 Max Consecutive Ones III Java Explanation Medium
☐ 1005 Maximize Sum Of Array After K Negations Java Explanation Easy
☐ 1006 Clumsy Factorial Java Explanation Medium
☐ 1007 Minimum Domino Rotations For Equal Row Java Explanation Medium
☐ 1008 Construct Binary Search Tree from Preorder Traversal Java Explanation Medium
☐ 1009 Complement of Base 10 Integer Java Explanation Easy
☐ 1010 Pairs of Songs With Total Durations Divisible by 60 Java Explanation Easy
☐ 1011 Capacity To Ship Packages Within D Days Java Explanation Medium
☐ 1012 Numbers With Repeated Digits Java Explanation Hard
☐ 1013 Partition Array Into Three Parts With Equal Sum Java Explanation Easy
☐ 1014 Best Sightseeing Pair Java Explanation Medium
☐ 1015 Smallest Integer Divisible by K Java Explanation Medium
☐ 1016 Binary String With Substrings Representing 1 To N Java Explanation Medium
☐ 1017 Convert to Base -2 Java Explanation Medium
☐ 1018 Binary Prefix Divisible By 5 Java Explanation Easy
☐ 1019 Next Greater Node In Linked List Java Explanation Medium
☐ 1020 Number of Enclaves Java Explanation Medium
☐ 1021 Remove Outermost Parentheses Java Explanation Easy
☐ 1022 Sum of Root To Leaf Binary Numbers Java Explanation Easy
☐ 1023 Camelcase Matching Java Explanation Medium
☐ 1024 Video Stitching Java Explanation Medium
☐ 1025 Divisor Game Java Explanation Easy
☐ 1026 Maximum Difference Between Node and Ancestor Java Explanation Medium
☐ 1027 Longest Arithmetic Sequence Java Explanation Medium
☐ 1028 Recover a Tree From Preorder Traversal Java Explanation Hard
☐ 1029 Two City Scheduling Java Explanation Easy
☐ 1030 Matrix Cells in Distance Order Java Explanation Easy
☐ 1031 Maximum Sum of Two Non-Overlapping Subarrays Java Explanation Medium
☐ 1032 Stream of Characters Java Explanation Hard
☐ 1033 Moving Stones Until Consecutive Java Explanation Easy
☐ 1034 Coloring A Border Java Explanation Medium
☐ 1035 Uncrossed Lines Java Explanation Medium
☐ 1036 Escape a Large Maze Java Explanation Hard
☐ 1037 Valid Boomerang Java Explanation Easy
☐ 1038 Binary Search Tree to Greater Sum Tree Java Explanation Medium
☐ 1039 Minimum Score Triangulation of Polygon Java Explanation Medium
☐ 1040 Moving Stones Until Consecutive II Java Explanation Medium
☐ 1041 Robot Bounded In Circle Java Explanation Medium
☐ 1042 Flower Planting With No Adjacent Java Explanation Easy
☐ 1043 Partition Array for Maximum Sum Java Explanation Medium
☐ 1044 Longest Duplicate Substring Java Explanation Hard
☐ 1046 Last Stone Weight Java Explanation Easy
☐ 1047 Remove All Adjacent Duplicates In String Java Explanation Easy
☐ 1048 Longest String Chain Java Explanation Medium
☐ 1049 Last Stone Weight II Java Explanation Medium
☐ 1051 Height Checker Java Explanation Easy
☐ 1052 Grumpy Bookstore Owner Java Explanation Medium
☐ 1053 Previous Permutation With One Swap Java Explanation Medium
☐ 1054 Distant Barcodes Java Explanation Medium
☐ 1055 Shortest Way to Form String Java Explanation Medium
☐ 1056 Confusing Number Java Explanation Easy
☐ 1057 Campus Bikes Java Explanation Medium
☐ 1058 Minimize Rounding Error to Meet Target Java Explanation Medium
☐ 1059 All Paths from Source Lead to Destination Java Explanation Medium
☐ 1060 Missing Element in Sorted Array Java Explanation Medium
☐ 1061 Lexicographically Smallest Equivalent String Java Explanation Medium
☐ 1062 Longest Repeating Substring Java Explanation Medium
☐ 1063 Number of Valid Subarrays Java Explanation Hard
☐ 1064 Fixed Point Java Explanation Easy
☐ 1065 Index Pairs of a String Java Explanation Easy
☐ 1066 Campus Bikes II Java Explanation Medium
☐ 1067 Digit Count in Range Java Explanation Hard
☐ 1071 Greatest Common Divisor of Strings Java Explanation Easy
☐ 1072 Flip Columns For Maximum Number of Equal Rows Java Explanation Medium
☐ 1073 Adding Two Negabinary Numbers Java Explanation Medium
☐ 1074 Number of Submatrices That Sum to Target Java Explanation Hard
☐ 1078 Occurrences After Bigram Java Explanation Easy
☐ 1079 Letter Tile Possibilities Java Explanation Medium
☐ 1080 Insufficient Nodes in Root to Leaf Paths Java Explanation Medium
☐ 1081 Smallest Subsequence of Distinct Characters Java Explanation Medium
☐ 1085 Sum of Digits in the Minimum Number Java Explanation Easy
☐ 1086 High Five Java Explanation Easy
☐ 1087 Brace Expansion Java Explanation Medium
☐ 1088 Confusing Number II Java Explanation Hard
☐ 1089 Duplicate Zeros Java Explanation Easy
☐ 1090 Largest Values From Labels Java Explanation Medium
☐ 1091 Shortest Path in Binary Matrix Java Explanation Medium
☐ 1092 Shortest Common Supersequence Java Explanation Hard
☐ 1093 Statistics from a Large Sample Java Explanation Medium
☐ 1094 Car Pooling Java Explanation Medium
☐ 1095 Find in Mountain Array Java Explanation Hard
☐ 1096 Brace Expansion II Java Explanation Hard
☐ 1099 Two Sum Less Than K Java Explanation Easy
☐ 1100 Find K-Length Substrings With No Repeated Characters Java Explanation Medium
☐ 1101 The Earliest Moment When Everyone Become Friends Java Explanation Medium
☐ 1102 Path With Maximum Minimum Value Java Explanation Medium
☐ 1103 Distribute Candies to People Java Explanation Easy
☐ 1104 Path In Zigzag Labelled Binary Tree Java Explanation Medium
☐ 1105 Filling Bookcase Shelves Java Explanation Medium
☐ 1106 Parsing A Boolean Expression Java Explanation Hard
☐ 1108 Defanging an IP Address Java Explanation Easy
☐ 1109 Corporate Flight Bookings Java Explanation Medium
☐ 1110 Delete Nodes And Return Forest Java Explanation Medium
☐ 1111 Maximum Nesting Depth of Two Valid Parentheses Strings Java Explanation Medium
☐ 1118 Number of Days in a Month Java Explanation Easy
☐ 1119 Remove Vowels from a String Java Explanation Easy
☐ 1120 Maximum Average Subtree Java Explanation Medium
☐ 1121 Divide Array Into Increasing Sequences Java Explanation Hard
☐ 1122 Relative Sort Array Java Explanation Easy
☐ 1123 Lowest Common Ancestor of Deepest Leaves Java Explanation Medium
☐ 1124 Longest Well-Performing Interval Java Explanation Medium
☐ 1125 Smallest Sufficient Team Java Explanation Hard
☐ 1128 Number of Equivalent Domino Pairs Java Explanation Easy
☐ 1129 Shortest Path with Alternating Colors Java Explanation Medium
☐ 1130 Minimum Cost Tree From Leaf Values Java Explanation Medium
☐ 1131 Maximum of Absolute Value Expression Java Explanation Medium
☐ 1133 Largest Unique Number Java Explanation Easy
☐ 1134 Armstrong Number Java Explanation Easy
☐ 1135 Connecting Cities With Minimum Cost Java Explanation Medium
☐ 1136 Parallel Courses Java Explanation Hard
☐ 1137 N-th Tribonacci Number Java Explanation Easy
☐ 1138 Alphabet Board Path Java Explanation Medium
☐ 1139 Largest 1-Bordered Square Java Explanation Medium
☐ 1140 Stone Game II Java Explanation Medium
☐ 1143 Longest Common Subsequence Java Explanation Medium
☐ 1144 Decrease Elements To Make Array Zigzag Java Explanation Medium
☐ 1145 Binary Tree Coloring Game Java Explanation Medium
☐ 1146 Snapshot Array Java Explanation Medium
☐ 1147 Longest Chunked Palindrome Decomposition Java Explanation Hard
☐ 1150 Check If a Number Is Majority Element in a Sorted Array Java Explanation Easy
☐ 1151 Minimum Swaps to Group All 1’s Together Java Explanation Medium
☐ 1152 Analyze User Website Visit Pattern Java Explanation Medium
☐ 1153 String Transforms Into Another String Java Explanation Hard
☐ 1154 Day of the Year Java Explanation Easy
☐ 1155 Number of Dice Rolls With Target Sum Java Explanation Medium
☐ 1156 Swap For Longest Repeated Character Substring Java Explanation Medium
☐ 1157 Online Majority Element In Subarray Java Explanation Hard
☐ 1160 Find Words That Can Be Formed by Characters Java Explanation Easy
☐ 1161 Maximum Level Sum of a Binary Tree Java Explanation Medium
☐ 1162 As Far from Land as Possible Java Explanation Medium
☐ 1163 Last Substring in Lexicographical Order Java Explanation Hard
☐ 1165 Single-Row Keyboard Java Explanation Easy
☐ 1166 Design File System Java Explanation Medium
☐ 1167 Minimum Cost to Connect Sticks Java Explanation Medium
☐ 1168 Optimize Water Distribution in a Village Java Explanation Hard
☐ 1169 Invalid Transactions Java Explanation Medium
☐ 1170 Compare Strings by Frequency of the Smallest Character Java Explanation Easy
☐ 1171 Remove Zero Sum Consecutive Nodes from Linked List Java Explanation Medium
☐ 1172 Dinner Plate Stacks Java Explanation Hard
☐ 1175 Prime Arrangements Java Explanation Easy
☐ 1176 Diet Plan Performance Java Explanation Easy
☐ 1177 Can Make Palindrome from Substring Java Explanation Medium
☐ 1178 Number of Valid Words for Each Puzzle Java Explanation Hard
☐ 1180 Count Substrings with Only One Distinct Letter Java Explanation Easy
☐ 1181 Before and After Puzzle Java Explanation Medium
☐ 1182 Shortest Distance to Target Color Java Explanation Medium
☐ 1183 Maximum Number of Ones Java Explanation Hard
☐ 1184 Distance Between Bus Stops Java Explanation Easy
☐ 1185 Day of the Week Java Explanation Easy
☐ 1186 Maximum Subarray Sum with One Deletion Java Explanation Medium
☐ 1187 Make Array Strictly Increasing Java Explanation Hard
☐ 1189 Maximum Number of Balloons Java Explanation Easy
☐ 1190 Reverse Substrings Between Each Pair of Parentheses Java Explanation Medium
☐ 1191 K-Concatenation Maximum Sum Java Explanation Medium
☐ 1192 Critical Connections in a Network Java Explanation Hard
☐ 1196 How Many Apples Can You Put into the Basket Java Explanation Easy
☐ 1197 Minimum Knight Moves Java Explanation Medium
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Do you have a better solution? Do you have a better explanation? Can you write the code cleaner?
If so, please email me at kidpiano.cs@gmail.com! If not, feel free to email me anyways 😊