QUESTIONS.md

List of Questions :

• 1 Two Sum (EASY)
• 2 Add Two Numbers (MEDIUM)
• 3 Longest Substring Without Repeating Characters (MEDIUM)
• 4 Median of Two Sorted Arrays (HARD)
• 5 Longest Palindromic Substring (MEDIUM)
• 6 ZigZag Conversion (MEDIUM)
• 7 Reverse Integer (EASY)
• 8 String to Integer (atoi) (MEDIUM)
• 9 Palindrome Number (EASY)
• 10 Regular Expression Matching (HARD)
• 11 Container With Most Water (MEDIUM)
• 12 Integer to Roman (MEDIUM)
• 13 Roman to Integer (EASY)
• 14 Longest Common Prefix (EASY)
• 15 3Sum (MEDIUM)
• 16 3Sum Closest (MEDIUM)
• 17 Letter Combinations of a Phone Number (MEDIUM)
• 18 4Sum (MEDIUM)
• 19 Remove Nth Node From End of List (MEDIUM)
• 20 Valid Parentheses (EASY)
• 21 Merge Two Sorted Lists (EASY)
• 22 Generate Parentheses (MEDIUM)
• 23 Merge k Sorted Lists (HARD)
• 24 Swap Nodes in Pairs (MEDIUM)
• 25 Reverse Nodes in k-Group (HARD)
• 26 Remove Duplicates from Sorted Array (EASY)
• 27 Remove Element (EASY)
• 28 Implement strStr() (EASY)
• 29 Divide Two Integers (MEDIUM)
• 30 Substring with Concatenation of All Words (HARD)
• 31 Next Permutation (MEDIUM)
• 32 Longest Valid Parentheses (HARD)
• 33 Search in Rotated Sorted Array (MEDIUM)
• 34 Find First and Last Position of Element in Sorted Array (MEDIUM)
• 35 Search Insert Position (EASY)
• 36 Valid Sudoku (MEDIUM)
• 37 Sudoku Solver (HARD)
• 38 Count and Say (MEDIUM)
• 39 Combination Sum (MEDIUM)
• 40 Combination Sum II (MEDIUM)
• 41 First Missing Positive (HARD)
• 42 Trapping Rain Water (HARD)
• 43 Multiply Strings (MEDIUM)
• 44 Wildcard Matching (HARD)
• 45 Jump Game II (MEDIUM)
• 46 Permutations (MEDIUM)
• 47 Permutations II (MEDIUM)
• 48 Rotate Image (MEDIUM)
• 49 Group Anagrams (MEDIUM)
• 50 Pow(x, n) (MEDIUM)
• 51 N-Queens (HARD)
• 52 N-Queens II (HARD)
• 53 Maximum Subarray (EASY)
• 54 Spiral Matrix (MEDIUM)
• 55 Jump Game (MEDIUM)
• 56 Merge Intervals (MEDIUM)
• 57 Insert Interval (MEDIUM)
• 58 Length of Last Word (EASY)
• 59 Spiral Matrix II (MEDIUM)
• 60 Permutation Sequence (HARD)
• 61 Rotate List (MEDIUM)
• 62 Unique Paths (MEDIUM)
• 63 Unique Paths II (MEDIUM)
• 64 Minimum Path Sum (MEDIUM)
• 65 Valid Number (HARD)
• 66 Plus One (EASY)
• 67 Add Binary (EASY)
• 68 Text Justification (HARD)
• 69 Sqrt(x) (EASY)
• 70 Climbing Stairs (EASY)
• 71 Simplify Path (MEDIUM)
• 72 Edit Distance (HARD)
• 73 Set Matrix Zeroes (MEDIUM)
• 74 Search a 2D Matrix (MEDIUM)
• 75 Sort Colors (MEDIUM)
• 76 Minimum Window Substring (HARD)
• 77 Combinations (MEDIUM)
• 78 Subsets (MEDIUM)
• 79 Word Search (MEDIUM)
• 80 Remove Duplicates from Sorted Array II (MEDIUM)
• 81 Search in Rotated Sorted Array II (MEDIUM)
• 82 Remove Duplicates from Sorted List II (MEDIUM)
• 83 Remove Duplicates from Sorted List (EASY)
• 84 Largest Rectangle in Histogram (HARD)
• 85 Maximal Rectangle (HARD)
• 86 Partition List (MEDIUM)
• 87 Scramble String (HARD)
• 88 Merge Sorted Array (EASY)
• 89 Gray Code (MEDIUM)
• 90 Subsets II (MEDIUM)
• 91 Decode Ways (MEDIUM)
• 92 Reverse Linked List II (MEDIUM)
• 93 Restore IP Addresses (MEDIUM)
• 94 Binary Tree Inorder Traversal (EASY)
• 95 Unique Binary Search Trees II (MEDIUM)
• 96 Unique Binary Search Trees (MEDIUM)
• 97 Interleaving String (MEDIUM)
• 98 Validate Binary Search Tree (MEDIUM)
• 99 Recover Binary Search Tree (MEDIUM)
• 100 Same Tree (EASY)
• 101 Symmetric Tree (EASY)
• 102 Binary Tree Level Order Traversal (MEDIUM)
• 103 Binary Tree Zigzag Level Order Traversal (MEDIUM)
• 104 Maximum Depth of Binary Tree (EASY)
• 105 Construct Binary Tree from Preorder and Inorder Traversal (MEDIUM)
• 106 Construct Binary Tree from Inorder and Postorder Traversal (MEDIUM)
• 107 Binary Tree Level Order Traversal II (MEDIUM)
• 108 Convert Sorted Array to Binary Search Tree (EASY)
• 109 Convert Sorted List to Binary Search Tree (MEDIUM)
• 110 Balanced Binary Tree (EASY)
• 111 Minimum Depth of Binary Tree (EASY)
• 112 Path Sum (EASY)
• 113 Path Sum II (MEDIUM)
• 114 Flatten Binary Tree to Linked List (MEDIUM)
• 115 Distinct Subsequences (HARD)
• 116 Populating Next Right Pointers in Each Node (MEDIUM)
• 117 Populating Next Right Pointers in Each Node II (MEDIUM)
• 118 Pascal's Triangle (EASY)
• 119 Pascal's Triangle II (EASY)
• 120 Triangle (MEDIUM)
• 121 Best Time to Buy and Sell Stock (EASY)
• 122 Best Time to Buy and Sell Stock II (MEDIUM)
• 123 Best Time to Buy and Sell Stock III (HARD)
• 124 Binary Tree Maximum Path Sum (HARD)
• 125 Valid Palindrome (EASY)
• 126 Word Ladder II (HARD)
• 127 Word Ladder (HARD)
• 128 Longest Consecutive Sequence (MEDIUM)
• 129 Sum Root to Leaf Numbers (MEDIUM)
• 130 Surrounded Regions (MEDIUM)
• 131 Palindrome Partitioning (MEDIUM)
• 132 Palindrome Partitioning II (HARD)
• 133 Clone Graph (MEDIUM)
• 134 Gas Station (MEDIUM)
• 135 Candy (HARD)
• 136 Single Number (EASY)
• 137 Single Number II (MEDIUM)
• 138 Copy List with Random Pointer (MEDIUM)
• 139 Word Break (MEDIUM)
• 140 Word Break II (HARD)
• 141 Linked List Cycle (EASY)
• 142 Linked List Cycle II (MEDIUM)
• 143 Reorder List (MEDIUM)
• 144 Binary Tree Preorder Traversal (EASY)
• 145 Binary Tree Postorder Traversal (EASY)
• 146 LRU Cache (MEDIUM)
• 147 Insertion Sort List (MEDIUM)
• 148 Sort List (MEDIUM)
• 149 Max Points on a Line (HARD)
• 150 Evaluate Reverse Polish Notation (MEDIUM)
• 151 Reverse Words in a String (MEDIUM)
• 152 Maximum Product Subarray (MEDIUM)
• 153 Find Minimum in Rotated Sorted Array (MEDIUM)
• 154 Find Minimum in Rotated Sorted Array II (HARD)
• 155 Min Stack (EASY)
• 156 Binary Tree Upside Down (MEDIUM) PREMIUM ONLY
• 157 Read N Characters Given Read4 (EASY) PREMIUM ONLY
• 158 Read N Characters Given Read4 II - Call multiple times (HARD) PREMIUM ONLY
• 159 Longest Substring with At Most Two Distinct Characters (MEDIUM) PREMIUM ONLY
• 160 Intersection of Two Linked Lists (EASY)
• 161 One Edit Distance (MEDIUM) PREMIUM ONLY
• 162 Find Peak Element (MEDIUM)
• 163 Missing Ranges (EASY) PREMIUM ONLY
• 164 Maximum Gap (HARD)
• 165 Compare Version Numbers (MEDIUM)
• 166 Fraction to Recurring Decimal (MEDIUM)
• 167 Two Sum II - Input array is sorted (EASY)
• 168 Excel Sheet Column Title (EASY)
• 169 Majority Element (EASY)
• 170 Two Sum III - Data structure design (EASY) PREMIUM ONLY
• 171 Excel Sheet Column Number (EASY)
• 172 Factorial Trailing Zeroes (EASY)
• 173 Binary Search Tree Iterator (MEDIUM)
• 174 Dungeon Game (HARD)
• 179 Largest Number (MEDIUM)
• 186 Reverse Words in a String II (MEDIUM) PREMIUM ONLY
• 187 Repeated DNA Sequences (MEDIUM)
• 188 Best Time to Buy and Sell Stock IV (HARD)
• 189 Rotate Array (MEDIUM)
• 190 Reverse Bits (EASY)
• 191 Number of 1 Bits (EASY)
• 198 House Robber (MEDIUM)
• 199 Binary Tree Right Side View (MEDIUM)
• 200 Number of Islands (MEDIUM)
• 201 Bitwise AND of Numbers Range (MEDIUM)
• 202 Happy Number (EASY)
• 203 Remove Linked List Elements (EASY)
• 204 Count Primes (MEDIUM)
• 205 Isomorphic Strings (EASY)
• 206 Reverse Linked List (EASY)
• 207 Course Schedule (MEDIUM)
• 208 Implement Trie (Prefix Tree) (MEDIUM)
• 209 Minimum Size Subarray Sum (MEDIUM)
• 210 Course Schedule II (MEDIUM)
• 211 Design Add and Search Words Data Structure (MEDIUM)
• 212 Word Search II (HARD)
• 213 House Robber II (MEDIUM)
• 214 Shortest Palindrome (HARD)
• 215 Kth Largest Element in an Array (MEDIUM)
• 216 Combination Sum III (MEDIUM)
• 217 Contains Duplicate (EASY)
• 218 The Skyline Problem (HARD)
• 219 Contains Duplicate II (EASY)
• 220 Contains Duplicate III (MEDIUM)
• 221 Maximal Square (MEDIUM)
• 222 Count Complete Tree Nodes (MEDIUM)
• 223 Rectangle Area (MEDIUM)
• 224 Basic Calculator (HARD)
• 225 Implement Stack using Queues (EASY)
• 226 Invert Binary Tree (EASY)
• 227 Basic Calculator II (MEDIUM)
• 228 Summary Ranges (EASY)
• 229 Majority Element II (MEDIUM)
• 230 Kth Smallest Element in a BST (MEDIUM)
• 231 Power of Two (EASY)
• 232 Implement Queue using Stacks (EASY)
• 233 Number of Digit One (HARD)
• 234 Palindrome Linked List (EASY)
• 235 Lowest Common Ancestor of a Binary Search Tree (EASY)
• 236 Lowest Common Ancestor of a Binary Tree (MEDIUM)
• 237 Delete Node in a Linked List (EASY)
• 238 Product of Array Except Self (MEDIUM)
• 239 Sliding Window Maximum (HARD)
• 240 Search a 2D Matrix II (MEDIUM)
• 241 Different Ways to Add Parentheses (MEDIUM)
• 242 Valid Anagram (EASY)
• 243 Shortest Word Distance (EASY) PREMIUM ONLY
• 244 Shortest Word Distance II (MEDIUM) PREMIUM ONLY
• 245 Shortest Word Distance III (MEDIUM) PREMIUM ONLY
• 246 Strobogrammatic Number (EASY) PREMIUM ONLY
• 247 Strobogrammatic Number II (MEDIUM) PREMIUM ONLY
• 248 Strobogrammatic Number III (HARD) PREMIUM ONLY
• 249 Group Shifted Strings (MEDIUM) PREMIUM ONLY
• 250 Count Univalue Subtrees (MEDIUM) PREMIUM ONLY
• 251 Flatten 2D Vector (MEDIUM) PREMIUM ONLY
• 252 Meeting Rooms (EASY) PREMIUM ONLY
• 253 Meeting Rooms II (MEDIUM) PREMIUM ONLY
• 254 Factor Combinations (MEDIUM) PREMIUM ONLY
• 255 Verify Preorder Sequence in Binary Search Tree (MEDIUM) PREMIUM ONLY
• 256 Paint House (MEDIUM) PREMIUM ONLY
• 257 Binary Tree Paths (EASY)
• 258 Add Digits (EASY)
• 259 3Sum Smaller (MEDIUM) PREMIUM ONLY
• 260 Single Number III (MEDIUM)
• 261 Graph Valid Tree (MEDIUM) PREMIUM ONLY
• 263 Ugly Number (EASY)
• 264 Ugly Number II (MEDIUM)
• 265 Paint House II (HARD) PREMIUM ONLY
• 266 Palindrome Permutation (EASY) PREMIUM ONLY
• 267 Palindrome Permutation II (MEDIUM) PREMIUM ONLY
• 268 Missing Number (EASY)
• 269 Alien Dictionary (HARD) PREMIUM ONLY
• 270 Closest Binary Search Tree Value (EASY) PREMIUM ONLY
• 271 Encode and Decode Strings (MEDIUM) PREMIUM ONLY
• 272 Closest Binary Search Tree Value II (HARD) PREMIUM ONLY
• 273 Integer to English Words (HARD)
• 274 H-Index (MEDIUM)
• 275 H-Index II (MEDIUM)
• 276 Paint Fence (MEDIUM) PREMIUM ONLY
• 277 Find the Celebrity (MEDIUM) PREMIUM ONLY
• 278 First Bad Version (EASY)
• 279 Perfect Squares (MEDIUM)
• 280 Wiggle Sort (MEDIUM) PREMIUM ONLY
• 281 Zigzag Iterator (MEDIUM) PREMIUM ONLY
• 282 Expression Add Operators (HARD)
• 283 Move Zeroes (EASY)
• 284 Peeking Iterator (MEDIUM)
• 285 Inorder Successor in BST (MEDIUM) PREMIUM ONLY
• 286 Walls and Gates (MEDIUM) PREMIUM ONLY
• 287 Find the Duplicate Number (MEDIUM)
• 288 Unique Word Abbreviation (MEDIUM) PREMIUM ONLY
• 289 Game of Life (MEDIUM)
• 290 Word Pattern (EASY)
• 291 Word Pattern II (MEDIUM) PREMIUM ONLY
• 292 Nim Game (EASY)
• 293 Flip Game (EASY) PREMIUM ONLY
• 294 Flip Game II (MEDIUM) PREMIUM ONLY
• 295 Find Median from Data Stream (HARD)
• 296 Best Meeting Point (HARD) PREMIUM ONLY
• 297 Serialize and Deserialize Binary Tree (HARD)
• 298 Binary Tree Longest Consecutive Sequence (MEDIUM) PREMIUM ONLY
• 299 Bulls and Cows (MEDIUM)
• 300 Longest Increasing Subsequence (MEDIUM)
• 301 Remove Invalid Parentheses (HARD)
• 302 Smallest Rectangle Enclosing Black Pixels (HARD) PREMIUM ONLY
• 303 Range Sum Query - Immutable (EASY)
• 304 Range Sum Query 2D - Immutable (MEDIUM)
• 305 Number of Islands II (HARD) PREMIUM ONLY
• 306 Additive Number (MEDIUM)
• 307 Range Sum Query - Mutable (MEDIUM)
• 308 Range Sum Query 2D - Mutable (HARD) PREMIUM ONLY
• 309 Best Time to Buy and Sell Stock with Cooldown (MEDIUM)
• 310 Minimum Height Trees (MEDIUM)
• 311 Sparse Matrix Multiplication (MEDIUM) PREMIUM ONLY
• 312 Burst Balloons (HARD)
• 313 Super Ugly Number (MEDIUM)
• 314 Binary Tree Vertical Order Traversal (MEDIUM) PREMIUM ONLY
• 315 Count of Smaller Numbers After Self (HARD)
• 316 Remove Duplicate Letters (MEDIUM)
• 317 Shortest Distance from All Buildings (HARD) PREMIUM ONLY
• 318 Maximum Product of Word Lengths (MEDIUM)
• 319 Bulb Switcher (MEDIUM)
• 320 Generalized Abbreviation (MEDIUM) PREMIUM ONLY
• 321 Create Maximum Number (HARD)
• 322 Coin Change (MEDIUM)
• 323 Number of Connected Components in an Undirected Graph (MEDIUM) PREMIUM ONLY
• 324 Wiggle Sort II (MEDIUM)
• 325 Maximum Size Subarray Sum Equals k (MEDIUM) PREMIUM ONLY
• 326 Power of Three (EASY)
• 327 Count of Range Sum (HARD)
• 328 Odd Even Linked List (MEDIUM)
• 329 Longest Increasing Path in a Matrix (HARD)
• 330 Patching Array (HARD)
• 331 Verify Preorder Serialization of a Binary Tree (MEDIUM)
• 332 Reconstruct Itinerary (MEDIUM)
• 333 Largest BST Subtree (MEDIUM) PREMIUM ONLY
• 334 Increasing Triplet Subsequence (MEDIUM)
• 335 Self Crossing (HARD)
• 336 Palindrome Pairs (HARD)
• 337 House Robber III (MEDIUM)
• 338 Counting Bits (EASY)
• 339 Nested List Weight Sum (MEDIUM) PREMIUM ONLY
• 340 Longest Substring with At Most K Distinct Characters (MEDIUM) PREMIUM ONLY
• 341 Flatten Nested List Iterator (MEDIUM)
• 342 Power of Four (EASY)
• 343 Integer Break (MEDIUM)
• 344 Reverse String (EASY)
• 345 Reverse Vowels of a String (EASY)
• 346 Moving Average from Data Stream (EASY) PREMIUM ONLY
• 347 Top K Frequent Elements (MEDIUM)
• 348 Design Tic-Tac-Toe (MEDIUM) PREMIUM ONLY
• 349 Intersection of Two Arrays (EASY)
• 350 Intersection of Two Arrays II (EASY)
• 351 Android Unlock Patterns (MEDIUM) PREMIUM ONLY
• 352 Data Stream as Disjoint Intervals (HARD)
• 353 Design Snake Game (MEDIUM) PREMIUM ONLY
• 354 Russian Doll Envelopes (HARD)
• 355 Design Twitter (MEDIUM)
• 356 Line Reflection (MEDIUM) PREMIUM ONLY
• 357 Count Numbers with Unique Digits (MEDIUM)
• 358 Rearrange String k Distance Apart (HARD) PREMIUM ONLY
• 359 Logger Rate Limiter (EASY) PREMIUM ONLY
• 360 Sort Transformed Array (MEDIUM) PREMIUM ONLY
• 361 Bomb Enemy (MEDIUM) PREMIUM ONLY
• 362 Design Hit Counter (MEDIUM) PREMIUM ONLY
• 363 Max Sum of Rectangle No Larger Than K (HARD)
• 364 Nested List Weight Sum II (MEDIUM) PREMIUM ONLY
• 365 Water and Jug Problem (MEDIUM)
• 366 Find Leaves of Binary Tree (MEDIUM) PREMIUM ONLY
• 367 Valid Perfect Square (EASY)
• 368 Largest Divisible Subset (MEDIUM)
• 369 Plus One Linked List (MEDIUM) PREMIUM ONLY
• 370 Range Addition (MEDIUM) PREMIUM ONLY
• 371 Sum of Two Integers (MEDIUM)
• 372 Super Pow (MEDIUM)
• 373 Find K Pairs with Smallest Sums (MEDIUM)
• 374 Guess Number Higher or Lower (EASY)
• 375 Guess Number Higher or Lower II (MEDIUM)
• 376 Wiggle Subsequence (MEDIUM)
• 377 Combination Sum IV (MEDIUM)
• 378 Kth Smallest Element in a Sorted Matrix (MEDIUM)
• 379 Design Phone Directory (MEDIUM) PREMIUM ONLY
• 380 Insert Delete GetRandom O(1) (MEDIUM)
• 381 Insert Delete GetRandom O(1) - Duplicates allowed (HARD)
• 382 Linked List Random Node (MEDIUM)
• 383 Ransom Note (EASY)
• 384 Shuffle an Array (MEDIUM)
• 385 Mini Parser (MEDIUM)
• 386 Lexicographical Numbers (MEDIUM)
• 387 First Unique Character in a String (EASY)
• 388 Longest Absolute File Path (MEDIUM)
• 389 Find the Difference (EASY)
• 390 Elimination Game (MEDIUM)
• 391 Perfect Rectangle (HARD)
• 392 Is Subsequence (EASY)
• 393 UTF-8 Validation (MEDIUM)
• 394 Decode String (MEDIUM)
• 395 Longest Substring with At Least K Repeating Characters (MEDIUM)
• 396 Rotate Function (MEDIUM)
• 397 Integer Replacement (MEDIUM)
• 398 Random Pick Index (MEDIUM)
• 399 Evaluate Division (MEDIUM)
• 400 Nth Digit (MEDIUM)
• 401 Binary Watch (EASY)
• 402 Remove K Digits (MEDIUM)
• 403 Frog Jump (HARD)
• 404 Sum of Left Leaves (EASY)
• 405 Convert a Number to Hexadecimal (EASY)
• 406 Queue Reconstruction by Height (MEDIUM)
• 407 Trapping Rain Water II (HARD)
• 408 Valid Word Abbreviation (EASY) PREMIUM ONLY
• 409 Longest Palindrome (EASY)
• 410 Split Array Largest Sum (HARD)
• 411 Minimum Unique Word Abbreviation (HARD) PREMIUM ONLY
• 412 Fizz Buzz (EASY)
• 413 Arithmetic Slices (MEDIUM)
• 414 Third Maximum Number (EASY)
• 415 Add Strings (EASY)
• 416 Partition Equal Subset Sum (MEDIUM)
• 417 Pacific Atlantic Water Flow (MEDIUM)
• 418 Sentence Screen Fitting (MEDIUM) PREMIUM ONLY
• 419 Battleships in a Board (MEDIUM)
• 420 Strong Password Checker (HARD)
• 421 Maximum XOR of Two Numbers in an Array (MEDIUM)
• 422 Valid Word Square (EASY) PREMIUM ONLY
• 423 Reconstruct Original Digits from English (MEDIUM)
• 424 Longest Repeating Character Replacement (MEDIUM)
• 425 Word Squares (HARD) PREMIUM ONLY
• 426 Convert Binary Search Tree to Sorted Doubly Linked List (MEDIUM) PREMIUM ONLY
• 427 Construct Quad Tree (MEDIUM)
• 428 Serialize and Deserialize N-ary Tree (HARD) PREMIUM ONLY
• 429 N-ary Tree Level Order Traversal (MEDIUM)
• 430 Flatten a Multilevel Doubly Linked List (MEDIUM)
• 431 Encode N-ary Tree to Binary Tree (HARD) PREMIUM ONLY
• 432 All O`one Data Structure (HARD)
• 433 Minimum Genetic Mutation (MEDIUM)
• 434 Number of Segments in a String (EASY)
• 435 Non-overlapping Intervals (MEDIUM)
• 436 Find Right Interval (MEDIUM)
• 437 Path Sum III (MEDIUM)
• 438 Find All Anagrams in a String (MEDIUM)
• 439 Ternary Expression Parser (MEDIUM) PREMIUM ONLY
• 440 K-th Smallest in Lexicographical Order (HARD)
• 441 Arranging Coins (EASY)
• 442 Find All Duplicates in an Array (MEDIUM)
• 443 String Compression (MEDIUM)
• 444 Sequence Reconstruction (MEDIUM) PREMIUM ONLY
• 445 Add Two Numbers II (MEDIUM)
• 446 Arithmetic Slices II - Subsequence (HARD)
• 447 Number of Boomerangs (MEDIUM)
• 448 Find All Numbers Disappeared in an Array (EASY)
• 449 Serialize and Deserialize BST (MEDIUM)
• 450 Delete Node in a BST (MEDIUM)
• 451 Sort Characters By Frequency (MEDIUM)
• 452 Minimum Number of Arrows to Burst Balloons (MEDIUM)
• 453 Minimum Moves to Equal Array Elements (EASY)
• 454 4Sum II (MEDIUM)
• 455 Assign Cookies (EASY)
• 456 132 Pattern (MEDIUM)
• 457 Circular Array Loop (MEDIUM)
• 458 Poor Pigs (HARD)
• 459 Repeated Substring Pattern (EASY)
• 460 LFU Cache (HARD)
• 461 Hamming Distance (EASY)
• 462 Minimum Moves to Equal Array Elements II (MEDIUM)
• 463 Island Perimeter (EASY)
• 464 Can I Win (MEDIUM)
• 465 Optimal Account Balancing (HARD) PREMIUM ONLY
• 466 Count The Repetitions (HARD)
• 467 Unique Substrings in Wraparound String (MEDIUM)
• 468 Validate IP Address (MEDIUM)
• 469 Convex Polygon (MEDIUM) PREMIUM ONLY
• 470 Implement Rand10() Using Rand7() (MEDIUM)
• 471 Encode String with Shortest Length (HARD) PREMIUM ONLY
• 472 Concatenated Words (HARD)
• 473 Matchsticks to Square (MEDIUM)
• 474 Ones and Zeroes (MEDIUM)
• 475 Heaters (MEDIUM)
• 476 Number Complement (EASY)
• 477 Total Hamming Distance (MEDIUM)
• 478 Generate Random Point in a Circle (MEDIUM)
• 479 Largest Palindrome Product (HARD)
• 480 Sliding Window Median (HARD)
• 481 Magical String (MEDIUM)
• 482 License Key Formatting (EASY)
• 483 Smallest Good Base (HARD)
• 484 Find Permutation (MEDIUM) PREMIUM ONLY
• 485 Max Consecutive Ones (EASY)
• 486 Predict the Winner (MEDIUM)
• 487 Max Consecutive Ones II (MEDIUM) PREMIUM ONLY
• 488 Zuma Game (HARD)
• 489 Robot Room Cleaner (HARD) PREMIUM ONLY
• 490 The Maze (MEDIUM) PREMIUM ONLY
• 491 Increasing Subsequences (MEDIUM)
• 492 Construct the Rectangle (EASY)
• 493 Reverse Pairs (HARD)
• 494 Target Sum (MEDIUM)
• 495 Teemo Attacking (EASY)
• 496 Next Greater Element I (EASY)
• 497 Random Point in Non-overlapping Rectangles (MEDIUM)
• 498 Diagonal Traverse (MEDIUM)
• 499 The Maze III (HARD) PREMIUM ONLY
• 500 Keyboard Row (EASY)
• 501 Find Mode in Binary Search Tree (EASY)
• 502 IPO (HARD)
• 503 Next Greater Element II (MEDIUM)
• 504 Base 7 (EASY)
• 505 The Maze II (MEDIUM) PREMIUM ONLY
• 506 Relative Ranks (EASY)
• 507 Perfect Number (EASY)
• 508 Most Frequent Subtree Sum (MEDIUM)
• 509 Fibonacci Number (EASY)
• 510 Inorder Successor in BST II (MEDIUM) PREMIUM ONLY
• 513 Find Bottom Left Tree Value (MEDIUM)
• 514 Freedom Trail (HARD)
• 515 Find Largest Value in Each Tree Row (MEDIUM)
• 516 Longest Palindromic Subsequence (MEDIUM)
• 517 Super Washing Machines (HARD)
• 518 Coin Change 2 (MEDIUM)
• 519 Random Flip Matrix (MEDIUM)
• 520 Detect Capital (EASY)
• 521 Longest Uncommon Subsequence I (EASY)
• 522 Longest Uncommon Subsequence II (MEDIUM)
• 523 Continuous Subarray Sum (MEDIUM)
• 524 Longest Word in Dictionary through Deleting (MEDIUM)
• 525 Contiguous Array (MEDIUM)
• 526 Beautiful Arrangement (MEDIUM)
• 527 Word Abbreviation (HARD) PREMIUM ONLY
• 528 Random Pick with Weight (MEDIUM)
• 529 Minesweeper (MEDIUM)
• 530 Minimum Absolute Difference in BST (EASY)
• 531 Lonely Pixel I (MEDIUM) PREMIUM ONLY
• 532 K-diff Pairs in an Array (MEDIUM)
• 533 Lonely Pixel II (MEDIUM) PREMIUM ONLY
• 535 Encode and Decode TinyURL (MEDIUM)
• 536 Construct Binary Tree from String (MEDIUM) PREMIUM ONLY
• 537 Complex Number Multiplication (MEDIUM)
• 538 Convert BST to Greater Tree (MEDIUM)
• 539 Minimum Time Difference (MEDIUM)
• 540 Single Element in a Sorted Array (MEDIUM)
• 541 Reverse String II (EASY)
• 542 01 Matrix (MEDIUM)
• 543 Diameter of Binary Tree (EASY)
• 544 Output Contest Matches (MEDIUM) PREMIUM ONLY
• 545 Boundary of Binary Tree (MEDIUM) PREMIUM ONLY
• 546 Remove Boxes (HARD)
• 547 Number of Provinces (MEDIUM)
• 548 Split Array with Equal Sum (HARD) PREMIUM ONLY
• 549 Binary Tree Longest Consecutive Sequence II (MEDIUM) PREMIUM ONLY
• 551 Student Attendance Record I (EASY)
• 552 Student Attendance Record II (HARD)
• 553 Optimal Division (MEDIUM)
• 554 Brick Wall (MEDIUM)
• 555 Split Concatenated Strings (MEDIUM) PREMIUM ONLY
• 556 Next Greater Element III (MEDIUM)
• 557 Reverse Words in a String III (EASY)
• 558 Logical OR of Two Binary Grids Represented as Quad-Trees (MEDIUM)
• 559 Maximum Depth of N-ary Tree (EASY)
• 560 Subarray Sum Equals K (MEDIUM)
• 561 Array Partition I (EASY)
• 562 Longest Line of Consecutive One in Matrix (MEDIUM) PREMIUM ONLY
• 563 Binary Tree Tilt (EASY)
• 564 Find the Closest Palindrome (HARD)
• 565 Array Nesting (MEDIUM)
• 566 Reshape the Matrix (EASY)
• 567 Permutation in String (MEDIUM)
• 568 Maximum Vacation Days (HARD) PREMIUM ONLY
• 572 Subtree of Another Tree (EASY)
• 573 Squirrel Simulation (MEDIUM) PREMIUM ONLY
• 575 Distribute Candies (EASY)
• 576 Out of Boundary Paths (MEDIUM)
• 581 Shortest Unsorted Continuous Subarray (MEDIUM)
• 582 Kill Process (MEDIUM) PREMIUM ONLY
• 583 Delete Operation for Two Strings (MEDIUM)
• 587 Erect the Fence (HARD)
• 588 Design In-Memory File System (HARD) PREMIUM ONLY
• 589 N-ary Tree Preorder Traversal (EASY)
• 590 N-ary Tree Postorder Traversal (EASY)
• 591 Tag Validator (HARD)
• 592 Fraction Addition and Subtraction (MEDIUM)
• 593 Valid Square (MEDIUM)
• 594 Longest Harmonious Subsequence (EASY)
• 598 Range Addition II (EASY)
• 599 Minimum Index Sum of Two Lists (EASY)
• 600 Non-negative Integers without Consecutive Ones (HARD)
• 604 Design Compressed String Iterator (EASY) PREMIUM ONLY
• 605 Can Place Flowers (EASY)
• 606 Construct String from Binary Tree (EASY)
• 609 Find Duplicate File in System (MEDIUM)
• 611 Valid Triangle Number (MEDIUM)
• 616 Add Bold Tag in String (MEDIUM) PREMIUM ONLY
• 617 Merge Two Binary Trees (EASY)
• 621 Task Scheduler (MEDIUM)
• 622 Design Circular Queue (MEDIUM)
• 623 Add One Row to Tree (MEDIUM)
• 624 Maximum Distance in Arrays (MEDIUM) PREMIUM ONLY
• 625 Minimum Factorization (MEDIUM) PREMIUM ONLY
• 628 Maximum Product of Three Numbers (EASY)
• 629 K Inverse Pairs Array (HARD)
• 630 Course Schedule III (HARD)
• 631 Design Excel Sum Formula (HARD) PREMIUM ONLY
• 632 Smallest Range Covering Elements from K Lists (HARD)
• 633 Sum of Square Numbers (MEDIUM)
• 634 Find the Derangement of An Array (MEDIUM) PREMIUM ONLY
• 635 Design Log Storage System (MEDIUM) PREMIUM ONLY
• 636 Exclusive Time of Functions (MEDIUM)
• 637 Average of Levels in Binary Tree (EASY)
• 638 Shopping Offers (MEDIUM)
• 639 Decode Ways II (HARD)
• 640 Solve the Equation (MEDIUM)
• 641 Design Circular Deque (MEDIUM)
• 642 Design Search Autocomplete System (HARD) PREMIUM ONLY
• 643 Maximum Average Subarray I (EASY)
• 644 Maximum Average Subarray II (HARD) PREMIUM ONLY
• 645 Set Mismatch (EASY)
• 646 Maximum Length of Pair Chain (MEDIUM)
• 647 Palindromic Substrings (MEDIUM)
• 648 Replace Words (MEDIUM)
• 649 Dota2 Senate (MEDIUM)
• 650 2 Keys Keyboard (MEDIUM)
• 651 4 Keys Keyboard (MEDIUM) PREMIUM ONLY
• 652 Find Duplicate Subtrees (MEDIUM)
• 653 Two Sum IV - Input is a BST (EASY)
• 654 Maximum Binary Tree (MEDIUM)
• 655 Print Binary Tree (MEDIUM)
• 656 Coin Path (HARD) PREMIUM ONLY
• 657 Robot Return to Origin (EASY)
• 658 Find K Closest Elements (MEDIUM)
• 659 Split Array into Consecutive Subsequences (MEDIUM)
• 660 Remove 9 (HARD) PREMIUM ONLY
• 661 Image Smoother (EASY)
• 662 Maximum Width of Binary Tree (MEDIUM)
• 663 Equal Tree Partition (MEDIUM) PREMIUM ONLY
• 664 Strange Printer (HARD)
• 665 Non-decreasing Array (MEDIUM)
• 666 Path Sum IV (MEDIUM) PREMIUM ONLY
• 667 Beautiful Arrangement II (MEDIUM)
• 668 Kth Smallest Number in Multiplication Table (HARD)
• 669 Trim a Binary Search Tree (MEDIUM)
• 670 Maximum Swap (MEDIUM)
• 671 Second Minimum Node In a Binary Tree (EASY)
• 672 Bulb Switcher II (MEDIUM)
• 673 Number of Longest Increasing Subsequence (MEDIUM)
• 674 Longest Continuous Increasing Subsequence (EASY)
• 675 Cut Off Trees for Golf Event (HARD)
• 676 Implement Magic Dictionary (MEDIUM)
• 677 Map Sum Pairs (MEDIUM)
• 678 Valid Parenthesis String (MEDIUM)
• 679 24 Game (HARD)
• 680 Valid Palindrome II (EASY)
• 681 Next Closest Time (MEDIUM) PREMIUM ONLY
• 682 Baseball Game (EASY)
• 683 K Empty Slots (HARD) PREMIUM ONLY
• 684 Redundant Connection (MEDIUM)
• 685 Redundant Connection II (HARD)
• 686 Repeated String Match (MEDIUM)
• 687 Longest Univalue Path (MEDIUM)
• 688 Knight Probability in Chessboard (MEDIUM)
• 689 Maximum Sum of 3 Non-Overlapping Subarrays (HARD)
• 690 Employee Importance (EASY)
• 691 Stickers to Spell Word (HARD)
• 692 Top K Frequent Words (MEDIUM)
• 693 Binary Number with Alternating Bits (EASY)
• 694 Number of Distinct Islands (MEDIUM) PREMIUM ONLY
• 695 Max Area of Island (MEDIUM)
• 696 Count Binary Substrings (EASY)
• 697 Degree of an Array (EASY)
• 698 Partition to K Equal Sum Subsets (MEDIUM)
• 699 Falling Squares (HARD)
• 700 Search in a Binary Search Tree (EASY)
• 701 Insert into a Binary Search Tree (MEDIUM)
• 702 Search in a Sorted Array of Unknown Size (MEDIUM) PREMIUM ONLY
• 703 Kth Largest Element in a Stream (EASY)
• 704 Binary Search (EASY)
• 705 Design HashSet (EASY)
• 706 Design HashMap (EASY)
• 707 Design Linked List (MEDIUM)
• 708 Insert into a Sorted Circular Linked List (MEDIUM) PREMIUM ONLY
• 709 To Lower Case (EASY)
• 710 Random Pick with Blacklist (HARD)
• 711 Number of Distinct Islands II (HARD) PREMIUM ONLY
• 712 Minimum ASCII Delete Sum for Two Strings (MEDIUM)
• 713 Subarray Product Less Than K (MEDIUM)
• 714 Best Time to Buy and Sell Stock with Transaction Fee (MEDIUM)
• 715 Range Module (HARD)
• 716 Max Stack (EASY) PREMIUM ONLY
• 717 1-bit and 2-bit Characters (EASY)
• 718 Maximum Length of Repeated Subarray (MEDIUM)
• 719 Find K-th Smallest Pair Distance (HARD)
• 720 Longest Word in Dictionary (MEDIUM)
• 721 Accounts Merge (MEDIUM)
• 722 Remove Comments (MEDIUM)
• 723 Candy Crush (MEDIUM) PREMIUM ONLY
• 724 Find Pivot Index (EASY)
• 725 Split Linked List in Parts (MEDIUM)
• 726 Number of Atoms (HARD)
• 727 Minimum Window Subsequence (HARD) PREMIUM ONLY
• 728 Self Dividing Numbers (EASY)
• 729 My Calendar I (MEDIUM)
• 730 Count Different Palindromic Subsequences (HARD)
• 731 My Calendar II (MEDIUM)
• 732 My Calendar III (HARD)
• 733 Flood Fill (EASY)
• 734 Sentence Similarity (EASY) PREMIUM ONLY
• 735 Asteroid Collision (MEDIUM)
• 736 Parse Lisp Expression (HARD)
• 737 Sentence Similarity II (MEDIUM) PREMIUM ONLY
• 738 Monotone Increasing Digits (MEDIUM)
• 739 Daily Temperatures (MEDIUM)
• 740 Delete and Earn (MEDIUM)
• 741 Cherry Pickup (HARD)
• 742 Closest Leaf in a Binary Tree (MEDIUM) PREMIUM ONLY
• 743 Network Delay Time (MEDIUM)
• 744 Find Smallest Letter Greater Than Target (EASY)
• 745 Prefix and Suffix Search (HARD)
• 746 Min Cost Climbing Stairs (EASY)
• 747 Largest Number At Least Twice of Others (EASY)
• 748 Shortest Completing Word (EASY)
• 749 Contain Virus (HARD)
• 750 Number Of Corner Rectangles (MEDIUM) PREMIUM ONLY
• 751 IP to CIDR (MEDIUM) PREMIUM ONLY
• 752 Open the Lock (MEDIUM)
• 753 Cracking the Safe (HARD)
• 754 Reach a Number (MEDIUM)
• 755 Pour Water (MEDIUM) PREMIUM ONLY
• 756 Pyramid Transition Matrix (MEDIUM)
• 757 Set Intersection Size At Least Two (HARD)
• 758 Bold Words in String (MEDIUM) PREMIUM ONLY
• 759 Employee Free Time (HARD) PREMIUM ONLY
• 760 Find Anagram Mappings (EASY) PREMIUM ONLY
• 761 Special Binary String (HARD)
• 762 Prime Number of Set Bits in Binary Representation (EASY)
• 763 Partition Labels (MEDIUM)
• 764 Largest Plus Sign (MEDIUM)
• 765 Couples Holding Hands (HARD)
• 766 Toeplitz Matrix (EASY)
• 767 Reorganize String (MEDIUM)
• 768 Max Chunks To Make Sorted II (HARD)
• 769 Max Chunks To Make Sorted (MEDIUM)
• 770 Basic Calculator IV (HARD)
• 771 Jewels and Stones (EASY)
• 772 Basic Calculator III (HARD) PREMIUM ONLY
• 773 Sliding Puzzle (HARD)
• 774 Minimize Max Distance to Gas Station (HARD) PREMIUM ONLY
• 775 Global and Local Inversions (MEDIUM)
• 776 Split BST (MEDIUM) PREMIUM ONLY
• 777 Swap Adjacent in LR String (MEDIUM)
• 778 Swim in Rising Water (HARD)
• 779 K-th Symbol in Grammar (MEDIUM)
• 780 Reaching Points (HARD)
• 781 Rabbits in Forest (MEDIUM)
• 782 Transform to Chessboard (HARD)
• 783 Minimum Distance Between BST Nodes (EASY)
• 784 Letter Case Permutation (MEDIUM)
• 785 Is Graph Bipartite? (MEDIUM)
• 786 K-th Smallest Prime Fraction (HARD)
• 787 Cheapest Flights Within K Stops (MEDIUM)
• 788 Rotated Digits (MEDIUM)
• 789 Escape The Ghosts (MEDIUM)
• 790 Domino and Tromino Tiling (MEDIUM)
• 791 Custom Sort String (MEDIUM)
• 792 Number of Matching Subsequences (MEDIUM)
• 793 Preimage Size of Factorial Zeroes Function (HARD)
• 794 Valid Tic-Tac-Toe State (MEDIUM)
• 795 Number of Subarrays with Bounded Maximum (MEDIUM)
• 796 Rotate String (EASY)
• 797 All Paths From Source to Target (MEDIUM)
• 798 Smallest Rotation with Highest Score (HARD)
• 799 Champagne Tower (MEDIUM)
• 800 Similar RGB Color (EASY) PREMIUM ONLY
• 801 Minimum Swaps To Make Sequences Increasing (HARD)
• 802 Find Eventual Safe States (MEDIUM)
• 803 Bricks Falling When Hit (HARD)
• 804 Unique Morse Code Words (EASY)
• 805 Split Array With Same Average (HARD)
• 806 Number of Lines To Write String (EASY)
• 807 Max Increase to Keep City Skyline (MEDIUM)
• 808 Soup Servings (MEDIUM)
• 809 Expressive Words (MEDIUM)
• 810 Chalkboard XOR Game (HARD)
• 811 Subdomain Visit Count (MEDIUM)
• 812 Largest Triangle Area (EASY)
• 813 Largest Sum of Averages (MEDIUM)
• 814 Binary Tree Pruning (MEDIUM)
• 815 Bus Routes (HARD)
• 816 Ambiguous Coordinates (MEDIUM)
• 817 Linked List Components (MEDIUM)
• 818 Race Car (HARD)
• 819 Most Common Word (EASY)
• 820 Short Encoding of Words (MEDIUM)
• 821 Shortest Distance to a Character (EASY)
• 822 Card Flipping Game (MEDIUM)
• 823 Binary Trees With Factors (MEDIUM)
• 824 Goat Latin (EASY)
• 825 Friends Of Appropriate Ages (MEDIUM)
• 826 Most Profit Assigning Work (MEDIUM)
• 827 Making A Large Island (HARD)
• 828 Count Unique Characters of All Substrings of a Given String (HARD)
• 829 Consecutive Numbers Sum (HARD)
• 830 Positions of Large Groups (EASY)
• 831 Masking Personal Information (MEDIUM)
• 832 Flipping an Image (EASY)
• 833 Find And Replace in String (MEDIUM)
• 834 Sum of Distances in Tree (HARD)
• 835 Image Overlap (MEDIUM)
• 836 Rectangle Overlap (EASY)
• 837 New 21 Game (MEDIUM)
• 838 Push Dominoes (MEDIUM)
• 839 Similar String Groups (HARD)
• 840 Magic Squares In Grid (MEDIUM)
• 841 Keys and Rooms (MEDIUM)
• 842 Split Array into Fibonacci Sequence (MEDIUM)
• 843 Guess the Word (HARD)
• 844 Backspace String Compare (EASY)
• 845 Longest Mountain in Array (MEDIUM)
• 846 Hand of Straights (MEDIUM)
• 847 Shortest Path Visiting All Nodes (HARD)
• 848 Shifting Letters (MEDIUM)
• 849 Maximize Distance to Closest Person (MEDIUM)
• 850 Rectangle Area II (HARD)
• 851 Loud and Rich (MEDIUM)
• 852 Peak Index in a Mountain Array (EASY)
• 853 Car Fleet (MEDIUM)
• 854 K-Similar Strings (HARD)
• 855 Exam Room (MEDIUM)
• 856 Score of Parentheses (MEDIUM)
• 857 Minimum Cost to Hire K Workers (HARD)
• 858 Mirror Reflection (MEDIUM)
• 859 Buddy Strings (EASY)
• 860 Lemonade Change (EASY)
• 861 Score After Flipping Matrix (MEDIUM)
• 862 Shortest Subarray with Sum at Least K (HARD)
• 863 All Nodes Distance K in Binary Tree (MEDIUM)
• 864 Shortest Path to Get All Keys (HARD)
• 865 Smallest Subtree with all the Deepest Nodes (MEDIUM)
• 866 Prime Palindrome (MEDIUM)
• 867 Transpose Matrix (EASY)
• 868 Binary Gap (EASY)
• 869 Reordered Power of 2 (MEDIUM)
• 870 Advantage Shuffle (MEDIUM)
• 871 Minimum Number of Refueling Stops (HARD)
• 872 Leaf-Similar Trees (EASY)
• 873 Length of Longest Fibonacci Subsequence (MEDIUM)
• 874 Walking Robot Simulation (EASY)
• 875 Koko Eating Bananas (MEDIUM)
• 876 Middle of the Linked List (EASY)
• 877 Stone Game (MEDIUM)
• 878 Nth Magical Number (HARD)
• 879 Profitable Schemes (HARD)
• 880 Decoded String at Index (MEDIUM)
• 881 Boats to Save People (MEDIUM)
• 882 Reachable Nodes In Subdivided Graph (HARD)
• 883 Projection Area of 3D Shapes (EASY)
• 884 Uncommon Words from Two Sentences (EASY)
• 885 Spiral Matrix III (MEDIUM)
• 886 Possible Bipartition (MEDIUM)
• 887 Super Egg Drop (HARD)
• 888 Fair Candy Swap (EASY)
• 889 Construct Binary Tree from Preorder and Postorder Traversal (MEDIUM)
• 890 Find and Replace Pattern (MEDIUM)
• 891 Sum of Subsequence Widths (HARD)
• 892 Surface Area of 3D Shapes (EASY)
• 893 Groups of Special-Equivalent Strings (MEDIUM)
• 894 All Possible Full Binary Trees (MEDIUM)
• 895 Maximum Frequency Stack (HARD)
• 896 Monotonic Array (EASY)
• 897 Increasing Order Search Tree (EASY)
• 898 Bitwise ORs of Subarrays (MEDIUM)
• 899 Orderly Queue (HARD)
• 900 RLE Iterator (MEDIUM)
• 901 Online Stock Span (MEDIUM)
• 902 Numbers At Most N Given Digit Set (HARD)
• 903 Valid Permutations for DI Sequence (HARD)
• 904 Fruit Into Baskets (MEDIUM)
• 905 Sort Array By Parity (EASY)
• 906 Super Palindromes (HARD)
• 907 Sum of Subarray Minimums (MEDIUM)
• 908 Smallest Range I (EASY)
• 909 Snakes and Ladders (MEDIUM)
• 910 Smallest Range II (MEDIUM)
• 911 Online Election (MEDIUM)
• 912 Sort an Array (MEDIUM)
• 913 Cat and Mouse (HARD)
• 914 X of a Kind in a Deck of Cards (EASY)
• 915 Partition Array into Disjoint Intervals (MEDIUM)
• 916 Word Subsets (MEDIUM)
• 917 Reverse Only Letters (EASY)
• 918 Maximum Sum Circular Subarray (MEDIUM)
• 919 Complete Binary Tree Inserter (MEDIUM)
• 920 Number of Music Playlists (HARD)
• 921 Minimum Add to Make Parentheses Valid (MEDIUM)
• 922 Sort Array By Parity II (EASY)
• 923 3Sum With Multiplicity (MEDIUM)
• 924 Minimize Malware Spread (HARD)
• 925 Long Pressed Name (EASY)
• 926 Flip String to Monotone Increasing (MEDIUM)
• 927 Three Equal Parts (HARD)
• 928 Minimize Malware Spread II (HARD)
• 929 Unique Email Addresses (EASY)
• 930 Binary Subarrays With Sum (MEDIUM)
• 931 Minimum Falling Path Sum (MEDIUM)
• 932 Beautiful Array (MEDIUM)
• 933 Number of Recent Calls (EASY)
• 934 Shortest Bridge (MEDIUM)
• 935 Knight Dialer (MEDIUM)
• 936 Stamping The Sequence (HARD)
• 937 Reorder Data in Log Files (EASY)
• 938 Range Sum of BST (EASY)
• 939 Minimum Area Rectangle (MEDIUM)
• 940 Distinct Subsequences II (HARD)
• 941 Valid Mountain Array (EASY)
• 942 DI String Match (EASY)
• 943 Find the Shortest Superstring (HARD)
• 944 Delete Columns to Make Sorted (EASY)
• 945 Minimum Increment to Make Array Unique (MEDIUM)
• 946 Validate Stack Sequences (MEDIUM)
• 947 Most Stones Removed with Same Row or Column (MEDIUM)
• 948 Bag of Tokens (MEDIUM)
• 949 Largest Time for Given Digits (MEDIUM)
• 950 Reveal Cards In Increasing Order (MEDIUM)
• 951 Flip Equivalent Binary Trees (MEDIUM)
• 952 Largest Component Size by Common Factor (HARD)
• 953 Verifying an Alien Dictionary (EASY)
• 954 Array of Doubled Pairs (MEDIUM)
• 955 Delete Columns to Make Sorted II (MEDIUM)
• 956 Tallest Billboard (HARD)
• 957 Prison Cells After N Days (MEDIUM)
• 958 Check Completeness of a Binary Tree (MEDIUM)
• 959 Regions Cut By Slashes (MEDIUM)
• 960 Delete Columns to Make Sorted III (HARD)
• 961 N-Repeated Element in Size 2N Array (EASY)
• 962 Maximum Width Ramp (MEDIUM)
• 963 Minimum Area Rectangle II (MEDIUM)
• 964 Least Operators to Express Number (HARD)
• 965 Univalued Binary Tree (EASY)
• 966 Vowel Spellchecker (MEDIUM)
• 967 Numbers With Same Consecutive Differences (MEDIUM)
• 968 Binary Tree Cameras (HARD)
• 969 Pancake Sorting (MEDIUM)
• 970 Powerful Integers (MEDIUM)
• 971 Flip Binary Tree To Match Preorder Traversal (MEDIUM)
• 972 Equal Rational Numbers (HARD)
• 973 K Closest Points to Origin (MEDIUM)
• 974 Subarray Sums Divisible by K (MEDIUM)
• 975 Odd Even Jump (HARD)
• 976 Largest Perimeter Triangle (EASY)
• 977 Squares of a Sorted Array (EASY)
• 978 Longest Turbulent Subarray (MEDIUM)
• 979 Distribute Coins in Binary Tree (MEDIUM)
• 980 Unique Paths III (HARD)
• 981 Time Based Key-Value Store (MEDIUM)
• 982 Triples with Bitwise AND Equal To Zero (HARD)
• 983 Minimum Cost For Tickets (MEDIUM)
• 984 String Without AAA or BBB (MEDIUM)
• 985 Sum of Even Numbers After Queries (MEDIUM)
• 986 Interval List Intersections (MEDIUM)
• 987 Vertical Order Traversal of a Binary Tree (HARD)
• 988 Smallest String Starting From Leaf (MEDIUM)
• 989 Add to Array-Form of Integer (EASY)
• 990 Satisfiability of Equality Equations (MEDIUM)
• 991 Broken Calculator (MEDIUM)
• 992 Subarrays with K Different Integers (HARD)
• 993 Cousins in Binary Tree (EASY)
• 994 Rotting Oranges (MEDIUM)
• 995 Minimum Number of K Consecutive Bit Flips (HARD)
• 996 Number of Squareful Arrays (HARD)
• 997 Find the Town Judge (EASY)
• 998 Maximum Binary Tree II (MEDIUM)
• 999 Available Captures for Rook (EASY)
• 1000 Minimum Cost to Merge Stones (HARD)
• 1001 Grid Illumination (HARD)
• 1002 Find Common Characters (EASY)
• 1003 Check If Word Is Valid After Substitutions (MEDIUM)
• 1004 Max Consecutive Ones III (MEDIUM)
• 1005 Maximize Sum Of Array After K Negations (EASY)
• 1006 Clumsy Factorial (MEDIUM)
• 1007 Minimum Domino Rotations For Equal Row (MEDIUM)
• 1008 Construct Binary Search Tree from Preorder Traversal (MEDIUM)
• 1009 Complement of Base 10 Integer (EASY)
• 1010 Pairs of Songs With Total Durations Divisible by 60 (MEDIUM)
• 1011 Capacity To Ship Packages Within D Days (MEDIUM)
• 1012 Numbers With Repeated Digits (HARD)
• 1013 Partition Array Into Three Parts With Equal Sum (EASY)
• 1014 Best Sightseeing Pair (MEDIUM)
• 1015 Smallest Integer Divisible by K (MEDIUM)
• 1016 Binary String With Substrings Representing 1 To N (MEDIUM)
• 1017 Convert to Base -2 (MEDIUM)
• 1018 Binary Prefix Divisible By 5 (EASY)
• 1019 Next Greater Node In Linked List (MEDIUM)
• 1020 Number of Enclaves (MEDIUM)
• 1021 Remove Outermost Parentheses (EASY)
• 1022 Sum of Root To Leaf Binary Numbers (EASY)
• 1023 Camelcase Matching (MEDIUM)
• 1024 Video Stitching (MEDIUM)
• 1025 Divisor Game (EASY)
• 1026 Maximum Difference Between Node and Ancestor (MEDIUM)
• 1027 Longest Arithmetic Subsequence (MEDIUM)
• 1028 Recover a Tree From Preorder Traversal (HARD)
• 1029 Two City Scheduling (MEDIUM)
• 1030 Matrix Cells in Distance Order (EASY)
• 1031 Maximum Sum of Two Non-Overlapping Subarrays (MEDIUM)
• 1032 Stream of Characters (HARD)
• 1033 Moving Stones Until Consecutive (MEDIUM)
• 1034 Coloring A Border (MEDIUM)
• 1035 Uncrossed Lines (MEDIUM)
• 1036 Escape a Large Maze (HARD)
• 1037 Valid Boomerang (EASY)
• 1038 Binary Search Tree to Greater Sum Tree (MEDIUM)
• 1039 Minimum Score Triangulation of Polygon (MEDIUM)
• 1040 Moving Stones Until Consecutive II (MEDIUM)
• 1041 Robot Bounded In Circle (MEDIUM)
• 1042 Flower Planting With No Adjacent (MEDIUM)
• 1043 Partition Array for Maximum Sum (MEDIUM)
• 1044 Longest Duplicate Substring (HARD)
• 1046 Last Stone Weight (EASY)
• 1047 Remove All Adjacent Duplicates In String (EASY)
• 1048 Longest String Chain (MEDIUM)
• 1049 Last Stone Weight II (MEDIUM)
• 1051 Height Checker (EASY)
• 1052 Grumpy Bookstore Owner (MEDIUM)
• 1053 Previous Permutation With One Swap (MEDIUM)
• 1054 Distant Barcodes (MEDIUM)
• 1055 Shortest Way to Form String (MEDIUM) PREMIUM ONLY
• 1056 Confusing Number (EASY) PREMIUM ONLY
• 1057 Campus Bikes (MEDIUM) PREMIUM ONLY
• 1058 Minimize Rounding Error to Meet Target (MEDIUM) PREMIUM ONLY
• 1059 All Paths from Source Lead to Destination (MEDIUM) PREMIUM ONLY
• 1060 Missing Element in Sorted Array (MEDIUM) PREMIUM ONLY
• 1061 Lexicographically Smallest Equivalent String (MEDIUM) PREMIUM ONLY
• 1062 Longest Repeating Substring (MEDIUM) PREMIUM ONLY
• 1063 Number of Valid Subarrays (HARD) PREMIUM ONLY
• 1064 Fixed Point (EASY) PREMIUM ONLY
• 1065 Index Pairs of a String (EASY) PREMIUM ONLY
• 1066 Campus Bikes II (MEDIUM) PREMIUM ONLY
• 1067 Digit Count in Range (HARD) PREMIUM ONLY
• 1071 Greatest Common Divisor of Strings (EASY)
• 1072 Flip Columns For Maximum Number of Equal Rows (MEDIUM)
• 1073 Adding Two Negabinary Numbers (MEDIUM)
• 1074 Number of Submatrices That Sum to Target (HARD)
• 1078 Occurrences After Bigram (EASY)
• 1079 Letter Tile Possibilities (MEDIUM)
• 1080 Insufficient Nodes in Root to Leaf Paths (MEDIUM)
• 1081 Smallest Subsequence of Distinct Characters (MEDIUM)
• 1085 Sum of Digits in the Minimum Number (EASY) PREMIUM ONLY
• 1086 High Five (EASY) PREMIUM ONLY
• 1087 Brace Expansion (MEDIUM) PREMIUM ONLY
• 1088 Confusing Number II (HARD) PREMIUM ONLY
• 1089 Duplicate Zeros (EASY)
• 1090 Largest Values From Labels (MEDIUM)
• 1091 Shortest Path in Binary Matrix (MEDIUM)
• 1092 Shortest Common Supersequence (HARD)
• 1093 Statistics from a Large Sample (MEDIUM)
• 1094 Car Pooling (MEDIUM)
• 1095 Find in Mountain Array (HARD)
• 1096 Brace Expansion II (HARD)
• 1099 Two Sum Less Than K (EASY) PREMIUM ONLY
• 1100 Find K-Length Substrings With No Repeated Characters (MEDIUM) PREMIUM ONLY
• 1101 The Earliest Moment When Everyone Become Friends (MEDIUM) PREMIUM ONLY
• 1102 Path With Maximum Minimum Value (MEDIUM) PREMIUM ONLY
• 1103 Distribute Candies to People (EASY)
• 1104 Path In Zigzag Labelled Binary Tree (MEDIUM)
• 1105 Filling Bookcase Shelves (MEDIUM)
• 1106 Parsing A Boolean Expression (HARD)
• 1108 Defanging an IP Address (EASY)
• 1109 Corporate Flight Bookings (MEDIUM)
• 1110 Delete Nodes And Return Forest (MEDIUM)
• 1111 Maximum Nesting Depth of Two Valid Parentheses Strings (MEDIUM)
• 1118 Number of Days in a Month (EASY) PREMIUM ONLY
• 1119 Remove Vowels from a String (EASY) PREMIUM ONLY
• 1120 Maximum Average Subtree (MEDIUM) PREMIUM ONLY
• 1121 Divide Array Into Increasing Sequences (HARD) PREMIUM ONLY
• 1122 Relative Sort Array (EASY)
• 1123 Lowest Common Ancestor of Deepest Leaves (MEDIUM)
• 1124 Longest Well-Performing Interval (MEDIUM)
• 1125 Smallest Sufficient Team (HARD)
• 1128 Number of Equivalent Domino Pairs (EASY)
• 1129 Shortest Path with Alternating Colors (MEDIUM)
• 1130 Minimum Cost Tree From Leaf Values (MEDIUM)
• 1131 Maximum of Absolute Value Expression (MEDIUM)
• 1133 Largest Unique Number (EASY) PREMIUM ONLY
• 1134 Armstrong Number (EASY) PREMIUM ONLY
• 1135 Connecting Cities With Minimum Cost (MEDIUM) PREMIUM ONLY
• 1136 Parallel Courses (MEDIUM) PREMIUM ONLY
• 1137 N-th Tribonacci Number (EASY)
• 1138 Alphabet Board Path (MEDIUM)
• 1139 Largest 1-Bordered Square (MEDIUM)
• 1140 Stone Game II (MEDIUM)
• 1143 Longest Common Subsequence (MEDIUM)
• 1144 Decrease Elements To Make Array Zigzag (MEDIUM)
• 1145 Binary Tree Coloring Game (MEDIUM)
• 1146 Snapshot Array (MEDIUM)
• 1147 Longest Chunked Palindrome Decomposition (HARD)
• 1150 Check If a Number Is Majority Element in a Sorted Array (EASY) PREMIUM ONLY
• 1151 Minimum Swaps to Group All 1's Together (MEDIUM) PREMIUM ONLY
• 1152 Analyze User Website Visit Pattern (MEDIUM) PREMIUM ONLY
• 1153 String Transforms Into Another String (HARD) PREMIUM ONLY
• 1154 Day of the Year (EASY)
• 1155 Number of Dice Rolls With Target Sum (MEDIUM)
• 1156 Swap For Longest Repeated Character Substring (MEDIUM)
• 1157 Online Majority Element In Subarray (HARD)
• 1160 Find Words That Can Be Formed by Characters (EASY)
• 1161 Maximum Level Sum of a Binary Tree (MEDIUM)
• 1162 As Far from Land as Possible (MEDIUM)
• 1163 Last Substring in Lexicographical Order (HARD)
• 1165 Single-Row Keyboard (EASY) PREMIUM ONLY
• 1166 Design File System (MEDIUM) PREMIUM ONLY
• 1167 Minimum Cost to Connect Sticks (MEDIUM) PREMIUM ONLY
• 1168 Optimize Water Distribution in a Village (HARD) PREMIUM ONLY
• 1169 Invalid Transactions (MEDIUM)
• 1170 Compare Strings by Frequency of the Smallest Character (MEDIUM)
• 1171 Remove Zero Sum Consecutive Nodes from Linked List (MEDIUM)
• 1172 Dinner Plate Stacks (HARD)
• 1175 Prime Arrangements (EASY)
• 1176 Diet Plan Performance (EASY) PREMIUM ONLY
• 1177 Can Make Palindrome from Substring (MEDIUM)
• 1178 Number of Valid Words for Each Puzzle (HARD)
• 1180 Count Substrings with Only One Distinct Letter (EASY) PREMIUM ONLY
• 1181 Before and After Puzzle (MEDIUM) PREMIUM ONLY
• 1182 Shortest Distance to Target Color (MEDIUM) PREMIUM ONLY
• 1183 Maximum Number of Ones (HARD) PREMIUM ONLY
• 1184 Distance Between Bus Stops (EASY)
• 1185 Day of the Week (EASY)
• 1186 Maximum Subarray Sum with One Deletion (MEDIUM)
• 1187 Make Array Strictly Increasing (HARD)
• 1189 Maximum Number of Balloons (EASY)
• 1190 Reverse Substrings Between Each Pair of Parentheses (MEDIUM)
• 1191 K-Concatenation Maximum Sum (MEDIUM)
• 1192 Critical Connections in a Network (HARD)
• 1196 How Many Apples Can You Put into the Basket (EASY) PREMIUM ONLY
• 1197 Minimum Knight Moves (MEDIUM) PREMIUM ONLY
• 1198 Find Smallest Common Element in All Rows (MEDIUM) PREMIUM ONLY
• 1199 Minimum Time to Build Blocks (HARD) PREMIUM ONLY
• 1200 Minimum Absolute Difference (EASY)
• 1201 Ugly Number III (MEDIUM)
• 1202 Smallest String With Swaps (MEDIUM)
• 1203 Sort Items by Groups Respecting Dependencies (HARD)
• 1206 Design Skiplist (HARD)
• 1207 Unique Number of Occurrences (EASY)
• 1208 Get Equal Substrings Within Budget (MEDIUM)
• 1209 Remove All Adjacent Duplicates in String II (MEDIUM)
• 1210 Minimum Moves to Reach Target with Rotations (HARD)
• 1213 Intersection of Three Sorted Arrays (EASY) PREMIUM ONLY
• 1214 Two Sum BSTs (MEDIUM) PREMIUM ONLY
• 1215 Stepping Numbers (MEDIUM) PREMIUM ONLY
• 1216 Valid Palindrome III (HARD) PREMIUM ONLY
• 1217 Minimum Cost to Move Chips to The Same Position (EASY)
• 1218 Longest Arithmetic Subsequence of Given Difference (MEDIUM)
• 1219 Path with Maximum Gold (MEDIUM)
• 1220 Count Vowels Permutation (HARD)
• 1221 Split a String in Balanced Strings (EASY)
• 1222 Queens That Can Attack the King (MEDIUM)
• 1223 Dice Roll Simulation (HARD)
• 1224 Maximum Equal Frequency (HARD)
• 1227 Airplane Seat Assignment Probability (MEDIUM)
• 1228 Missing Number In Arithmetic Progression (EASY) PREMIUM ONLY
• 1229 Meeting Scheduler (MEDIUM) PREMIUM ONLY
• 1230 Toss Strange Coins (MEDIUM) PREMIUM ONLY
• 1231 Divide Chocolate (HARD) PREMIUM ONLY
• 1232 Check If It Is a Straight Line (EASY)
• 1233 Remove Sub-Folders from the Filesystem (MEDIUM)
• 1234 Replace the Substring for Balanced String (MEDIUM)
• 1235 Maximum Profit in Job Scheduling (HARD)
• 1236 Web Crawler (MEDIUM) PREMIUM ONLY
• 1237 Find Positive Integer Solution for a Given Equation (MEDIUM)
• 1238 Circular Permutation in Binary Representation (MEDIUM)
• 1239 Maximum Length of a Concatenated String with Unique Characters (MEDIUM)
• 1240 Tiling a Rectangle with the Fewest Squares (HARD)
• 1243 Array Transformation (EASY) PREMIUM ONLY
• 1244 Design A Leaderboard (MEDIUM) PREMIUM ONLY
• 1245 Tree Diameter (MEDIUM) PREMIUM ONLY
• 1246 Palindrome Removal (HARD) PREMIUM ONLY
• 1247 Minimum Swaps to Make Strings Equal (MEDIUM)
• 1248 Count Number of Nice Subarrays (MEDIUM)
• 1249 Minimum Remove to Make Valid Parentheses (MEDIUM)
• 1250 Check If It Is a Good Array (HARD)
• 1252 Cells with Odd Values in a Matrix (EASY)
• 1253 Reconstruct a 2-Row Binary Matrix (MEDIUM)
• 1254 Number of Closed Islands (MEDIUM)
• 1255 Maximum Score Words Formed by Letters (HARD)
• 1256 Encode Number (MEDIUM) PREMIUM ONLY
• 1257 Smallest Common Region (MEDIUM) PREMIUM ONLY
• 1258 Synonymous Sentences (MEDIUM) PREMIUM ONLY
• 1259 Handshakes That Don't Cross (HARD) PREMIUM ONLY
• 1260 Shift 2D Grid (EASY)
• 1261 Find Elements in a Contaminated Binary Tree (MEDIUM)
• 1262 Greatest Sum Divisible by Three (MEDIUM)
• 1263 Minimum Moves to Move a Box to Their Target Location (HARD)
• 1265 Print Immutable Linked List in Reverse (MEDIUM) PREMIUM ONLY
• 1266 Minimum Time Visiting All Points (EASY)
• 1267 Count Servers that Communicate (MEDIUM)
• 1268 Search Suggestions System (MEDIUM)
• 1269 Number of Ways to Stay in the Same Place After Some Steps (HARD)
• 1271 Hexspeak (EASY) PREMIUM ONLY
• 1272 Remove Interval (MEDIUM) PREMIUM ONLY
• 1273 Delete Tree Nodes (MEDIUM) PREMIUM ONLY
• 1274 Number of Ships in a Rectangle (HARD) PREMIUM ONLY
• 1275 Find Winner on a Tic Tac Toe Game (EASY)
• 1276 Number of Burgers with No Waste of Ingredients (MEDIUM)
• 1277 Count Square Submatrices with All Ones (MEDIUM)
• 1278 Palindrome Partitioning III (HARD)
• 1281 Subtract the Product and Sum of Digits of an Integer (EASY)
• 1282 Group the People Given the Group Size They Belong To (MEDIUM)
• 1283 Find the Smallest Divisor Given a Threshold (MEDIUM)
• 1284 Minimum Number of Flips to Convert Binary Matrix to Zero Matrix (HARD)
• 1286 Iterator for Combination (MEDIUM)
• 1287 Element Appearing More Than 25% In Sorted Array (EASY)
• 1288 Remove Covered Intervals (MEDIUM)
• 1289 Minimum Falling Path Sum II (HARD)
• 1290 Convert Binary Number in a Linked List to Integer (EASY)
• 1291 Sequential Digits (MEDIUM)
• 1292 Maximum Side Length of a Square with Sum Less than or Equal to Threshold (MEDIUM)
• 1293 Shortest Path in a Grid with Obstacles Elimination (HARD)
• 1295 Find Numbers with Even Number of Digits (EASY)
• 1296 Divide Array in Sets of K Consecutive Numbers (MEDIUM)
• 1297 Maximum Number of Occurrences of a Substring (MEDIUM)
• 1298 Maximum Candies You Can Get from Boxes (HARD)
• 1299 Replace Elements with Greatest Element on Right Side (EASY)
• 1300 Sum of Mutated Array Closest to Target (MEDIUM)
• 1301 Number of Paths with Max Score (HARD)
• 1302 Deepest Leaves Sum (MEDIUM)
• 1304 Find N Unique Integers Sum up to Zero (EASY)
• 1305 All Elements in Two Binary Search Trees (MEDIUM)
• 1306 Jump Game III (MEDIUM)
• 1307 Verbal Arithmetic Puzzle (HARD)
• 1309 Decrypt String from Alphabet to Integer Mapping (EASY)
• 1310 XOR Queries of a Subarray (MEDIUM)
• 1311 Get Watched Videos by Your Friends (MEDIUM)
• 1312 Minimum Insertion Steps to Make a String Palindrome (HARD)
• 1313 Decompress Run-Length Encoded List (EASY)
• 1314 Matrix Block Sum (MEDIUM)
• 1315 Sum of Nodes with Even-Valued Grandparent (MEDIUM)
• 1316 Distinct Echo Substrings (HARD)
• 1317 Convert Integer to the Sum of Two No-Zero Integers (EASY)
• 1318 Minimum Flips to Make a OR b Equal to c (MEDIUM)
• 1319 Number of Operations to Make Network Connected (MEDIUM)
• 1320 Minimum Distance to Type a Word Using Two Fingers (HARD)
• 1323 Maximum 69 Number (EASY)
• 1324 Print Words Vertically (MEDIUM)
• 1325 Delete Leaves With a Given Value (MEDIUM)
• 1326 Minimum Number of Taps to Open to Water a Garden (HARD)
• 1328 Break a Palindrome (MEDIUM)
• 1329 Sort the Matrix Diagonally (MEDIUM)
• 1330 Reverse Subarray To Maximize Array Value (HARD)
• 1331 Rank Transform of an Array (EASY)
• 1332 Remove Palindromic Subsequences (EASY)
• 1333 Filter Restaurants by Vegan-Friendly, Price and Distance (MEDIUM)
• 1334 Find the City With the Smallest Number of Neighbors at a Threshold Distance (MEDIUM)
• 1335 Minimum Difficulty of a Job Schedule (HARD)
• 1337 The K Weakest Rows in a Matrix (EASY)
• 1338 Reduce Array Size to The Half (MEDIUM)
• 1339 Maximum Product of Splitted Binary Tree (MEDIUM)
• 1340 Jump Game V (HARD)
• 1342 Number of Steps to Reduce a Number to Zero (EASY)
• 1343 Number of Sub-arrays of Size K and Average Greater than or Equal to Threshold (MEDIUM)
• 1344 Angle Between Hands of a Clock (MEDIUM)
• 1345 Jump Game IV (HARD)
• 1346 Check If N and Its Double Exist (EASY)
• 1347 Minimum Number of Steps to Make Two Strings Anagram (MEDIUM)
• 1348 Tweet Counts Per Frequency (MEDIUM)
• 1349 Maximum Students Taking Exam (HARD)
• 1351 Count Negative Numbers in a Sorted Matrix (EASY)
• 1352 Product of the Last K Numbers (MEDIUM)
• 1353 Maximum Number of Events That Can Be Attended (MEDIUM)
• 1354 Construct Target Array With Multiple Sums (HARD)
• 1356 Sort Integers by The Number of 1 Bits (EASY)
• 1357 Apply Discount Every n Orders (MEDIUM)
• 1358 Number of Substrings Containing All Three Characters (MEDIUM)
• 1359 Count All Valid Pickup and Delivery Options (HARD)
• 1360 Number of Days Between Two Dates (EASY)
• 1361 Validate Binary Tree Nodes (MEDIUM)
• 1362 Closest Divisors (MEDIUM)
• 1363 Largest Multiple of Three (HARD)
• 1365 How Many Numbers Are Smaller Than the Current Number (EASY)
• 1366 Rank Teams by Votes (MEDIUM)
• 1367 Linked List in Binary Tree (MEDIUM)
• 1368 Minimum Cost to Make at Least One Valid Path in a Grid (HARD)
• 1370 Increasing Decreasing String (EASY)
• 1371 Find the Longest Substring Containing Vowels in Even Counts (MEDIUM)
• 1372 Longest ZigZag Path in a Binary Tree (MEDIUM)
• 1373 Maximum Sum BST in Binary Tree (HARD)
• 1374 Generate a String With Characters That Have Odd Counts (EASY)
• 1375 Bulb Switcher III (MEDIUM)
• 1376 Time Needed to Inform All Employees (MEDIUM)
• 1377 Frog Position After T Seconds (HARD)
• 1379 Find a Corresponding Node of a Binary Tree in a Clone of That Tree (MEDIUM)
• 1380 Lucky Numbers in a Matrix (EASY)
• 1381 Design a Stack With Increment Operation (MEDIUM)
• 1382 Balance a Binary Search Tree (MEDIUM)
• 1383 Maximum Performance of a Team (HARD)
• 1385 Find the Distance Value Between Two Arrays (EASY)
• 1386 Cinema Seat Allocation (MEDIUM)
• 1387 Sort Integers by The Power Value (MEDIUM)
• 1388 Pizza With 3n Slices (HARD)
• 1389 Create Target Array in the Given Order (EASY)
• 1390 Four Divisors (MEDIUM)
• 1391 Check if There is a Valid Path in a Grid (MEDIUM)
• 1392 Longest Happy Prefix (HARD)
• 1394 Find Lucky Integer in an Array (EASY)
• 1395 Count Number of Teams (MEDIUM)
• 1396 Design Underground System (MEDIUM)
• 1397 Find All Good Strings (HARD)
• 1399 Count Largest Group (EASY)
• 1400 Construct K Palindrome Strings (MEDIUM)
• 1401 Circle and Rectangle Overlapping (MEDIUM)
• 1402 Reducing Dishes (HARD)
• 1403 Minimum Subsequence in Non-Increasing Order (EASY)
• 1404 Number of Steps to Reduce a Number in Binary Representation to One (MEDIUM)
• 1405 Longest Happy String (MEDIUM)
• 1406 Stone Game III (HARD)
• 1408 String Matching in an Array (EASY)
• 1409 Queries on a Permutation With Key (MEDIUM)
• 1410 HTML Entity Parser (MEDIUM)
• 1411 Number of Ways to Paint N × 3 Grid (HARD)
• 1413 Minimum Value to Get Positive Step by Step Sum (EASY)
• 1414 Find the Minimum Number of Fibonacci Numbers Whose Sum Is K (MEDIUM)
• 1415 The k-th Lexicographical String of All Happy Strings of Length n (MEDIUM)
• 1416 Restore The Array (HARD)
• 1417 Reformat The String (EASY)
• 1418 Display Table of Food Orders in a Restaurant (MEDIUM)
• 1419 Minimum Number of Frogs Croaking (MEDIUM)
• 1420 Build Array Where You Can Find The Maximum Exactly K Comparisons (HARD)
• 1422 Maximum Score After Splitting a String (EASY)
• 1423 Maximum Points You Can Obtain from Cards (MEDIUM)
• 1424 Diagonal Traverse II (MEDIUM)
• 1425 Constrained Subsequence Sum (HARD)
• 1426 Counting Elements (EASY) PREMIUM ONLY
• 1427 Perform String Shifts (EASY) PREMIUM ONLY
• 1428 Leftmost Column with at Least a One (MEDIUM) PREMIUM ONLY
• 1429 First Unique Number (MEDIUM) PREMIUM ONLY
• 1430 Check If a String Is a Valid Sequence from Root to Leaves Path in a Binary Tree (MEDIUM) PREMIUM ONLY
• 1431 Kids With the Greatest Number of Candies (EASY)
• 1432 Max Difference You Can Get From Changing an Integer (MEDIUM)
• 1433 Check If a String Can Break Another String (MEDIUM)
• 1434 Number of Ways to Wear Different Hats to Each Other (HARD)
• 1436 Destination City (EASY)
• 1437 Check If All 1's Are at Least Length K Places Away (EASY)
• 1438 Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit (MEDIUM)
• 1439 Find the Kth Smallest Sum of a Matrix With Sorted Rows (HARD)
• 1441 Build an Array With Stack Operations (EASY)
• 1442 Count Triplets That Can Form Two Arrays of Equal XOR (MEDIUM)
• 1443 Minimum Time to Collect All Apples in a Tree (MEDIUM)
• 1444 Number of Ways of Cutting a Pizza (HARD)
• 1446 Consecutive Characters (EASY)
• 1447 Simplified Fractions (MEDIUM)
• 1448 Count Good Nodes in Binary Tree (MEDIUM)
• 1449 Form Largest Integer With Digits That Add up to Target (HARD)
• 1450 Number of Students Doing Homework at a Given Time (EASY)
• 1451 Rearrange Words in a Sentence (MEDIUM)
• 1452 People Whose List of Favorite Companies Is Not a Subset of Another List (MEDIUM)
• 1453 Maximum Number of Darts Inside of a Circular Dartboard (HARD)
• 1455 Check If a Word Occurs As a Prefix of Any Word in a Sentence (EASY)
• 1456 Maximum Number of Vowels in a Substring of Given Length (MEDIUM)
• 1457 Pseudo-Palindromic Paths in a Binary Tree (MEDIUM)
• 1458 Max Dot Product of Two Subsequences (HARD)
• 1460 Make Two Arrays Equal by Reversing Sub-arrays (EASY)
• 1461 Check If a String Contains All Binary Codes of Size K (MEDIUM)
• 1462 Course Schedule IV (MEDIUM)
• 1463 Cherry Pickup II (HARD)
• 1464 Maximum Product of Two Elements in an Array (EASY)
• 1465 Maximum Area of a Piece of Cake After Horizontal and Vertical Cuts (MEDIUM)
• 1466 Reorder Routes to Make All Paths Lead to the City Zero (MEDIUM)
• 1467 Probability of a Two Boxes Having The Same Number of Distinct Balls (HARD)
• 1469 Find All The Lonely Nodes (EASY) PREMIUM ONLY
• 1470 Shuffle the Array (EASY)
• 1471 The k Strongest Values in an Array (MEDIUM)
• 1472 Design Browser History (MEDIUM)
• 1473 Paint House III (HARD)
• 1474 Delete N Nodes After M Nodes of a Linked List (EASY) PREMIUM ONLY
• 1475 Final Prices With a Special Discount in a Shop (EASY)
• 1476 Subrectangle Queries (MEDIUM)
• 1477 Find Two Non-overlapping Sub-arrays Each With Target Sum (MEDIUM)
• 1478 Allocate Mailboxes (HARD)
• 1480 Running Sum of 1d Array (EASY)
• 1481 Least Number of Unique Integers after K Removals (MEDIUM)
• 1482 Minimum Number of Days to Make m Bouquets (MEDIUM)
• 1483 Kth Ancestor of a Tree Node (HARD)
• 1485 Clone Binary Tree With Random Pointer (MEDIUM) PREMIUM ONLY
• 1486 XOR Operation in an Array (EASY)
• 1487 Making File Names Unique (MEDIUM)
• 1488 Avoid Flood in The City (MEDIUM)
• 1489 Find Critical and Pseudo-Critical Edges in Minimum Spanning Tree (HARD)
• 1490 Clone N-ary Tree (MEDIUM) PREMIUM ONLY
• 1491 Average Salary Excluding the Minimum and Maximum Salary (EASY)
• 1492 The kth Factor of n (MEDIUM)
• 1493 Longest Subarray of 1's After Deleting One Element (MEDIUM)
• 1494 Parallel Courses II (HARD)
• 1496 Path Crossing (EASY)
• 1497 Check If Array Pairs Are Divisible by k (MEDIUM)
• 1498 Number of Subsequences That Satisfy the Given Sum Condition (MEDIUM)
• 1499 Max Value of Equation (HARD)
• 1500 Design a File Sharing System (MEDIUM) PREMIUM ONLY
• 1502 Can Make Arithmetic Progression From Sequence (EASY)
• 1503 Last Moment Before All Ants Fall Out of a Plank (MEDIUM)
• 1504 Count Submatrices With All Ones (MEDIUM)
• 1505 Minimum Possible Integer After at Most K Adjacent Swaps On Digits (HARD)
• 1506 Find Root of N-Ary Tree (MEDIUM) PREMIUM ONLY
• 1507 Reformat Date (EASY)
• 1508 Range Sum of Sorted Subarray Sums (MEDIUM)
• 1509 Minimum Difference Between Largest and Smallest Value in Three Moves (MEDIUM)
• 1510 Stone Game IV (HARD)
• 1512 Number of Good Pairs (EASY)
• 1513 Number of Substrings With Only 1s (MEDIUM)
• 1514 Path with Maximum Probability (MEDIUM)
• 1515 Best Position for a Service Centre (HARD)
• 1516 Move Sub-Tree of N-Ary Tree (HARD) PREMIUM ONLY
• 1518 Water Bottles (EASY)
• 1519 Number of Nodes in the Sub-Tree With the Same Label (MEDIUM)
• 1520 Maximum Number of Non-Overlapping Substrings (HARD)
• 1521 Find a Value of a Mysterious Function Closest to Target (HARD)
• 1522 Diameter of N-Ary Tree (MEDIUM) PREMIUM ONLY
• 1523 Count Odd Numbers in an Interval Range (EASY)
• 1524 Number of Sub-arrays With Odd Sum (MEDIUM)
• 1525 Number of Good Ways to Split a String (MEDIUM)
• 1526 Minimum Number of Increments on Subarrays to Form a Target Array (HARD)
• 1528 Shuffle String (EASY)
• 1529 Bulb Switcher IV (MEDIUM)
• 1530 Number of Good Leaf Nodes Pairs (MEDIUM)
• 1531 String Compression II (HARD)
• 1533 Find the Index of the Large Integer (MEDIUM) PREMIUM ONLY
• 1534 Count Good Triplets (EASY)
• 1535 Find the Winner of an Array Game (MEDIUM)
• 1536 Minimum Swaps to Arrange a Binary Grid (MEDIUM)
• 1537 Get the Maximum Score (HARD)
• 1538 Guess the Majority in a Hidden Array (MEDIUM) PREMIUM ONLY
• 1539 Kth Missing Positive Number (EASY)
• 1540 Can Convert String in K Moves (MEDIUM)
• 1541 Minimum Insertions to Balance a Parentheses String (MEDIUM)
• 1542 Find Longest Awesome Substring (HARD)
• 1544 Make The String Great (EASY)
• 1545 Find Kth Bit in Nth Binary String (MEDIUM)
• 1546 Maximum Number of Non-Overlapping Subarrays With Sum Equals Target (MEDIUM)
• 1547 Minimum Cost to Cut a Stick (HARD)
• 1548 The Most Similar Path in a Graph (HARD) PREMIUM ONLY
• 1550 Three Consecutive Odds (EASY)
• 1551 Minimum Operations to Make Array Equal (MEDIUM)
• 1552 Magnetic Force Between Two Balls (MEDIUM)
• 1553 Minimum Number of Days to Eat N Oranges (HARD)
• 1554 Strings Differ by One Character (MEDIUM) PREMIUM ONLY
• 1556 Thousand Separator (EASY)
• 1557 Minimum Number of Vertices to Reach All Nodes (MEDIUM)
• 1558 Minimum Numbers of Function Calls to Make Target Array (MEDIUM)
• 1559 Detect Cycles in 2D Grid (MEDIUM)
• 1560 Most Visited Sector in a Circular Track (EASY)
• 1561 Maximum Number of Coins You Can Get (MEDIUM)
• 1562 Find Latest Group of Size M (MEDIUM)
• 1563 Stone Game V (HARD)
• 1564 Put Boxes Into the Warehouse I (MEDIUM) PREMIUM ONLY
• 1566 Detect Pattern of Length M Repeated K or More Times (EASY)
• 1567 Maximum Length of Subarray With Positive Product (MEDIUM)
• 1568 Minimum Number of Days to Disconnect Island (HARD)
• 1569 Number of Ways to Reorder Array to Get Same BST (HARD)
• 1570 Dot Product of Two Sparse Vectors (MEDIUM) PREMIUM ONLY
• 1572 Matrix Diagonal Sum (EASY)
• 1573 Number of Ways to Split a String (MEDIUM)
• 1574 Shortest Subarray to be Removed to Make Array Sorted (MEDIUM)
• 1575 Count All Possible Routes (HARD)
• 1576 Replace All ?'s to Avoid Consecutive Repeating Characters (EASY)
• 1577 Number of Ways Where Square of Number Is Equal to Product of Two Numbers (MEDIUM)
• 1578 Minimum Deletion Cost to Avoid Repeating Letters (MEDIUM)
• 1579 Remove Max Number of Edges to Keep Graph Fully Traversable (HARD)
• 1580 Put Boxes Into the Warehouse II (MEDIUM) PREMIUM ONLY
• 1582 Special Positions in a Binary Matrix (EASY)
• 1583 Count Unhappy Friends (MEDIUM)
• 1584 Min Cost to Connect All Points (MEDIUM)
• 1585 Check If String Is Transformable With Substring Sort Operations (HARD)
• 1586 Binary Search Tree Iterator II (MEDIUM) PREMIUM ONLY
• 1588 Sum of All Odd Length Subarrays (EASY)
• 1589 Maximum Sum Obtained of Any Permutation (MEDIUM)
• 1590 Make Sum Divisible by P (MEDIUM)
• 1591 Strange Printer II (HARD)
• 1592 Rearrange Spaces Between Words (EASY)
• 1593 Split a String Into the Max Number of Unique Substrings (MEDIUM)
• 1594 Maximum Non Negative Product in a Matrix (MEDIUM)
• 1595 Minimum Cost to Connect Two Groups of Points (HARD)
• 1597 Build Binary Expression Tree From Infix Expression (HARD) PREMIUM ONLY
• 1598 Crawler Log Folder (EASY)
• 1599 Maximum Profit of Operating a Centennial Wheel (MEDIUM)
• 1600 Throne Inheritance (MEDIUM)
• 1601 Maximum Number of Achievable Transfer Requests (HARD)
• 1602 Find Nearest Right Node in Binary Tree (MEDIUM) PREMIUM ONLY
• 1603 Design Parking System (EASY)
• 1604 Alert Using Same Key-Card Three or More Times in a One Hour Period (MEDIUM)
• 1605 Find Valid Matrix Given Row and Column Sums (MEDIUM)
• 1606 Find Servers That Handled Most Number of Requests (HARD)
• 1608 Special Array With X Elements Greater Than or Equal X (EASY)
• 1609 Even Odd Tree (MEDIUM)
• 1610 Maximum Number of Visible Points (HARD)
• 1611 Minimum One Bit Operations to Make Integers Zero (HARD)
• 1612 Check If Two Expression Trees are Equivalent (MEDIUM) PREMIUM ONLY
• 1614 Maximum Nesting Depth of the Parentheses (EASY)
• 1615 Maximal Network Rank (MEDIUM)
• 1616 Split Two Strings to Make Palindrome (MEDIUM)
• 1617 Count Subtrees With Max Distance Between Cities (HARD)
• 1618 Maximum Font to Fit a Sentence in a Screen (MEDIUM) PREMIUM ONLY
• 1619 Mean of Array After Removing Some Elements (EASY)
• 1620 Coordinate With Maximum Network Quality (MEDIUM)
• 1621 Number of Sets of K Non-Overlapping Line Segments (MEDIUM)
• 1622 Fancy Sequence (HARD)
• 1624 Largest Substring Between Two Equal Characters (EASY)
• 1625 Lexicographically Smallest String After Applying Operations (MEDIUM)
• 1626 Best Team With No Conflicts (MEDIUM)
• 1627 Graph Connectivity With Threshold (HARD)
• 1628 Design an Expression Tree With Evaluate Function (MEDIUM) PREMIUM ONLY
• 1629 Slowest Key (EASY)
• 1630 Arithmetic Subarrays (MEDIUM)
• 1631 Path With Minimum Effort (MEDIUM)
• 1632 Rank Transform of a Matrix (HARD)
• 1634 Add Two Polynomials Represented as Linked Lists (MEDIUM) PREMIUM ONLY
• 1636 Sort Array by Increasing Frequency (EASY)
• 1637 Widest Vertical Area Between Two Points Containing No Points (MEDIUM)
• 1638 Count Substrings That Differ by One Character (MEDIUM)
• 1639 Number of Ways to Form a Target String Given a Dictionary (HARD)
• 1640 Check Array Formation Through Concatenation (EASY)
• 1641 Count Sorted Vowel Strings (MEDIUM)
• 1642 Furthest Building You Can Reach (MEDIUM)
• 1643 Kth Smallest Instructions (HARD)
• 1644 Lowest Common Ancestor of a Binary Tree II (MEDIUM) PREMIUM ONLY
• 1646 Get Maximum in Generated Array (EASY)
• 1647 Minimum Deletions to Make Character Frequencies Unique (MEDIUM)
• 1648 Sell Diminishing-Valued Colored Balls (MEDIUM)
• 1649 Create Sorted Array through Instructions (HARD)
• 1650 Lowest Common Ancestor of a Binary Tree III (MEDIUM) PREMIUM ONLY
• 1652 Defuse the Bomb (EASY)
• 1653 Minimum Deletions to Make String Balanced (MEDIUM)
• 1654 Minimum Jumps to Reach Home (MEDIUM)
• 1655 Distribute Repeating Integers (HARD)
• 1656 Design an Ordered Stream (EASY)
• 1657 Determine if Two Strings Are Close (MEDIUM)
• 1658 Minimum Operations to Reduce X to Zero (MEDIUM)
• 1659 Maximize Grid Happiness (HARD)
• 1660 Correct a Binary Tree (MEDIUM) PREMIUM ONLY
• 1662 Check If Two String Arrays are Equivalent (EASY)
• 1663 Smallest String With A Given Numeric Value (MEDIUM)
• 1664 Ways to Make a Fair Array (MEDIUM)
• 1665 Minimum Initial Energy to Finish Tasks (HARD)
• 1666 Change the Root of a Binary Tree (MEDIUM) PREMIUM ONLY
• 1668 Maximum Repeating Substring (EASY)
• 1669 Merge In Between Linked Lists (MEDIUM)
• 1670 Design Front Middle Back Queue (MEDIUM)
• 1671 Minimum Number of Removals to Make Mountain Array (HARD)
• 1672 Richest Customer Wealth (EASY)
• 1673 Find the Most Competitive Subsequence (MEDIUM)
• 1674 Minimum Moves to Make Array Complementary (MEDIUM)
• 1675 Minimize Deviation in Array (HARD)
• 1676 Lowest Common Ancestor of a Binary Tree IV (MEDIUM) PREMIUM ONLY
• 1678 Goal Parser Interpretation (EASY)
• 1679 Max Number of K-Sum Pairs (MEDIUM)
• 1680 Concatenation of Consecutive Binary Numbers (MEDIUM)
• 1681 Minimum Incompatibility (HARD)
• 1682 Longest Palindromic Subsequence II (MEDIUM) PREMIUM ONLY
• 1684 Count the Number of Consistent Strings (EASY)
• 1685 Sum of Absolute Differences in a Sorted Array (MEDIUM)
• 1686 Stone Game VI (MEDIUM)
• 1687 Delivering Boxes from Storage to Ports (HARD)
• 1688 Count of Matches in Tournament (EASY)
• 1689 Partitioning Into Minimum Number Of Deci-Binary Numbers (MEDIUM)
• 1690 Stone Game VII (MEDIUM)
• 1691 Maximum Height by Stacking Cuboids (HARD)
• 1692 Count Ways to Distribute Candies (HARD) PREMIUM ONLY
• 1694 Reformat Phone Number (EASY)
• 1695 Maximum Erasure Value (MEDIUM)
• 1696 Jump Game VI (MEDIUM)
• 1697 Checking Existence of Edge Length Limited Paths (HARD)
• 1698 Number of Distinct Substrings in a String (MEDIUM) PREMIUM ONLY
• 1700 Number of Students Unable to Eat Lunch (EASY)
• 1701 Average Waiting Time (MEDIUM)
• 1702 Maximum Binary String After Change (MEDIUM)
• 1703 Minimum Adjacent Swaps for K Consecutive Ones (HARD)
• 1704 Determine if String Halves Are Alike (EASY)
• 1705 Maximum Number of Eaten Apples (MEDIUM)
• 1706 Where Will the Ball Fall (MEDIUM)
• 1707 Maximum XOR With an Element From Array (HARD)
• 1708 Largest Subarray Length K (EASY) PREMIUM ONLY
• 1710 Maximum Units on a Truck (EASY)
• 1711 Count Good Meals (MEDIUM)
• 1712 Ways to Split Array Into Three Subarrays (MEDIUM)
• 1713 Minimum Operations to Make a Subsequence (HARD)
• 1714 Sum Of Special Evenly-Spaced Elements In Array (HARD) PREMIUM ONLY
• 1716 Calculate Money in Leetcode Bank (EASY)
• 1717 Maximum Score From Removing Substrings (MEDIUM)
• 1718 Construct the Lexicographically Largest Valid Sequence (MEDIUM)
• 1719 Number Of Ways To Reconstruct A Tree (HARD)
• 1720 Decode XORed Array (EASY)
• 1721 Swapping Nodes in a Linked List (MEDIUM)
• 1722 Minimize Hamming Distance After Swap Operations (MEDIUM)
• 1723 Find Minimum Time to Finish All Jobs (HARD)
• 1724 Checking Existence of Edge Length Limited Paths II (HARD) PREMIUM ONLY
• 1725 Number Of Rectangles That Can Form The Largest Square (EASY)
• 1726 Tuple with Same Product (MEDIUM)
• 1727 Largest Submatrix With Rearrangements (MEDIUM)
• 1728 Cat and Mouse II (HARD)
• 1730 Shortest Path to Get Food (MEDIUM) PREMIUM ONLY
• 1732 Find the Highest Altitude (EASY)
• 1733 Minimum Number of People to Teach (MEDIUM)
• 1734 Decode XORed Permutation (MEDIUM)
• 1735 Count Ways to Make Array With Product (HARD)
• 1736 Latest Time by Replacing Hidden Digits (EASY)
• 1737 Change Minimum Characters to Satisfy One of Three Conditions (MEDIUM)
• 1738 Find Kth Largest XOR Coordinate Value (MEDIUM)
• 1739 Building Boxes (HARD)
• 1740 Find Distance in a Binary Tree (MEDIUM) PREMIUM ONLY
• 1742 Maximum Number of Balls in a Box (EASY)
• 1743 Restore the Array From Adjacent Pairs (MEDIUM)
• 1744 Can You Eat Your Favorite Candy on Your Favorite Day? (MEDIUM)
• 1745 Palindrome Partitioning IV (HARD)
• 1746 Maximum Subarray Sum After One Operation (MEDIUM) PREMIUM ONLY
• 1748 Sum of Unique Elements (EASY)
• 1749 Maximum Absolute Sum of Any Subarray (MEDIUM)
• 1750 Minimum Length of String After Deleting Similar Ends (MEDIUM)
• 1751 Maximum Number of Events That Can Be Attended II (HARD)
• 1752 Check if Array Is Sorted and Rotated (EASY)
• 1753 Maximum Score From Removing Stones (MEDIUM)
• 1754 Largest Merge Of Two Strings (MEDIUM)
• 1755 Closest Subsequence Sum (HARD)
• 1756 Design Most Recently Used Queue (MEDIUM) PREMIUM ONLY
• 1758 Minimum Changes To Make Alternating Binary String (EASY)
• 1759 Count Number of Homogenous Substrings (MEDIUM)
• 1760 Minimum Limit of Balls in a Bag (MEDIUM)
• 1761 Minimum Degree of a Connected Trio in a Graph (HARD)
• 1762 Buildings With an Ocean View (MEDIUM) PREMIUM ONLY
• 1763 Longest Nice Substring (EASY)
• 1764 Form Array by Concatenating Subarrays of Another Array (MEDIUM)
• 1765 Map of Highest Peak (MEDIUM)
• 1766 Tree of Coprimes (HARD)
• 1768 Merge Strings Alternately (EASY)
• 1769 Minimum Number of Operations to Move All Balls to Each Box (MEDIUM)
• 1770 Maximum Score from Performing Multiplication Operations (MEDIUM)
• 1771 Maximize Palindrome Length From Subsequences (HARD)
• 1772 Sort Features by Popularity (MEDIUM) PREMIUM ONLY
• 1773 Count Items Matching a Rule (EASY)
• 1774 Closest Dessert Cost (MEDIUM)
• 1775 Equal Sum Arrays With Minimum Number of Operations (MEDIUM)
• 1776 Car Fleet II (HARD)
• 1778 Shortest Path in a Hidden Grid (MEDIUM) PREMIUM ONLY
• 1779 Find Nearest Point That Has the Same X or Y Coordinate (EASY)
• 1780 Check if Number is a Sum of Powers of Three (MEDIUM)
• 1781 Sum of Beauty of All Substrings (MEDIUM)
• 1782 Count Pairs Of Nodes (HARD)
• 1784 Check if Binary String Has at Most One Segment of Ones (EASY)
• 1785 Minimum Elements to Add to Form a Given Sum (MEDIUM)
• 1786 Number of Restricted Paths From First to Last Node (MEDIUM)
• 1787 Make the XOR of All Segments Equal to Zero (HARD)
• 1788 Maximize the Beauty of the Garden (HARD) PREMIUM ONLY
• 1790 Check if One String Swap Can Make Strings Equal (EASY)
• 1791 Find Center of Star Graph (EASY)
• 1792 Maximum Average Pass Ratio (MEDIUM)
• 1793 Maximum Score of a Good Subarray (HARD)
• 1794 Count Pairs of Equal Substrings With Minimum Difference (MEDIUM) PREMIUM ONLY
• 1796 Second Largest Digit in a String (EASY)
• 1797 Design Authentication Manager (MEDIUM)
• 1798 Maximum Number of Consecutive Values You Can Make (MEDIUM)
• 1799 Maximize Score After N Operations (HARD)
• 1800 Maximum Ascending Subarray Sum (EASY)
• 1801 Number of Orders in the Backlog (MEDIUM)
• 1802 Maximum Value at a Given Index in a Bounded Array (MEDIUM)
• 1803 Count Pairs With XOR in a Range (HARD)
• 1804 Implement Trie II (Prefix Tree) (MEDIUM) PREMIUM ONLY
• 1805 Number of Different Integers in a String (EASY)
• 1806 Minimum Number of Operations to Reinitialize a Permutation (MEDIUM)
• 1807 Evaluate the Bracket Pairs of a String (MEDIUM)
• 1808 Maximize Number of Nice Divisors (HARD)
• 1810 Minimum Path Cost in a Hidden Grid (MEDIUM) PREMIUM ONLY
• 1812 Determine Color of a Chessboard Square (EASY)
• 1813 Sentence Similarity III (MEDIUM)
• 1814 Count Nice Pairs in an Array (MEDIUM)
• 1815 Maximum Number of Groups Getting Fresh Donuts (HARD)
• 1816 Truncate Sentence (EASY)
• 1817 Finding the Users Active Minutes (MEDIUM)
• 1818 Minimum Absolute Sum Difference (MEDIUM)
• 1819 Number of Different Subsequences GCDs (HARD)
• 1820 Maximum Number of Accepted Invitations (MEDIUM) PREMIUM ONLY
• 1822 Sign of the Product of an Array (EASY)
• 1823 Find the Winner of the Circular Game (MEDIUM)
• 1824 Minimum Sideway Jumps (MEDIUM)
• 1825 Finding MK Average (HARD)
• 1826 Faulty Sensor (EASY) PREMIUM ONLY
• 1827 Minimum Operations to Make the Array Increasing (EASY)
• 1828 Queries on Number of Points Inside a Circle (MEDIUM)
• 1829 Maximum XOR for Each Query (MEDIUM)
• 1830 Minimum Number of Operations to Make String Sorted (HARD)
• 1832 Check if the Sentence Is Pangram (EASY)
• 1833 Maximum Ice Cream Bars (MEDIUM)
• 1834 Single-Threaded CPU (MEDIUM)
• 1835 Find XOR Sum of All Pairs Bitwise AND (HARD)
• 1836 Remove Duplicates From an Unsorted Linked List (MEDIUM) PREMIUM ONLY
• 1837 Sum of Digits in Base K (EASY)
• 1838 Frequency of the Most Frequent Element (MEDIUM)
• 1839 Longest Substring Of All Vowels in Order (MEDIUM)
• 1840 Maximum Building Height (HARD)
• 1842 Next Palindrome Using Same Digits (HARD) PREMIUM ONLY
• 1844 Replace All Digits with Characters (EASY)
• 1845 Seat Reservation Manager (MEDIUM)
• 1846 Maximum Element After Decreasing and Rearranging (MEDIUM)
• 1847 Closest Room (HARD)
• 1848 Minimum Distance to the Target Element (EASY)
• 1849 Splitting a String Into Descending Consecutive Values (MEDIUM)
• 1850 Minimum Adjacent Swaps to Reach the Kth Smallest Number (MEDIUM)
• 1851 Minimum Interval to Include Each Query (HARD)
• 1852 Distinct Numbers in Each Subarray (MEDIUM) PREMIUM ONLY
• 1854 Maximum Population Year (EASY)
• 1855 Maximum Distance Between a Pair of Values (MEDIUM)
• 1856 Maximum Subarray Min-Product (MEDIUM)
• 1857 Largest Color Value in a Directed Graph (HARD)
• 1858 Longest Word With All Prefixes (MEDIUM) PREMIUM ONLY
• 1859 Sorting the Sentence (EASY)
• 1860 Incremental Memory Leak (MEDIUM)
• 1861 Rotating the Box (MEDIUM)
• 1862 Sum of Floored Pairs (HARD)
• 1863 Sum of All Subset XOR Totals (EASY)
• 1864 Minimum Number of Swaps to Make the Binary String Alternating (MEDIUM)
• 1865 Finding Pairs With a Certain Sum (MEDIUM)
• 1866 Number of Ways to Rearrange Sticks With K Sticks Visible (HARD)
• 1868 Product of Two Run-Length Encoded Arrays (MEDIUM) PREMIUM ONLY
• 1869 Longer Contiguous Segments of Ones than Zeros (EASY)
• 1870 Minimum Speed to Arrive on Time (MEDIUM)
• 1871 Jump Game VII (MEDIUM)
• 1872 Stone Game VIII (HARD)
• 1874 Minimize Product Sum of Two Arrays (MEDIUM) PREMIUM ONLY
• 1876 Substrings of Size Three with Distinct Characters (EASY)
• 1877 Minimize Maximum Pair Sum in Array (MEDIUM)
• 1878 Get Biggest Three Rhombus Sums in a Grid (MEDIUM)
• 1879 Minimum XOR Sum of Two Arrays (HARD)
• 1880 Check if Word Equals Summation of Two Words (EASY)
• 1881 Maximum Value after Insertion (MEDIUM)
• 1882 Process Tasks Using Servers (MEDIUM)
• 1883 Minimum Skips to Arrive at Meeting On Time (HARD)
• 1884 Egg Drop With 2 Eggs and N Floors (MEDIUM)
• 1885 Count Pairs in Two Arrays (MEDIUM) PREMIUM ONLY
• 1886 Determine Whether Matrix Can Be Obtained By Rotation (EASY)
• 1887 Reduction Operations to Make the Array Elements Equal (MEDIUM)
• 1888 Minimum Number of Flips to Make the Binary String Alternating (MEDIUM)
• 1889 Minimum Space Wasted From Packaging (HARD)
• 1891 Cutting Ribbons (MEDIUM) PREMIUM ONLY
• 1893 Check if All the Integers in a Range Are Covered (EASY)
• 1894 Find the Student that Will Replace the Chalk (MEDIUM)
• 1895 Largest Magic Square (MEDIUM)
• 1896 Minimum Cost to Change the Final Value of Expression (HARD)
• 1897 Redistribute Characters to Make All Strings Equal (EASY)
• 1898 Maximum Number of Removable Characters (MEDIUM)
• 1899 Merge Triplets to Form Target Triplet (MEDIUM)
• 1900 The Earliest and Latest Rounds Where Players Compete (HARD)
• 1901 Find a Peak Element II (MEDIUM)
• 1902 Depth of BST Given Insertion Order (MEDIUM) PREMIUM ONLY
• 1903 Largest Odd Number in String (EASY)
• 1904 The Number of Full Rounds You Have Played (MEDIUM)
• 1905 Count Sub Islands (MEDIUM)
• 1906 Minimum Absolute Difference Queries (MEDIUM)
• 1908 Game of Nim (MEDIUM) PREMIUM ONLY
• 1909 Remove One Element to Make the Array Strictly Increasing (EASY)
• 1910 Remove All Occurrences of a Substring (MEDIUM)
• 1911 Maximum Alternating Subsequence Sum (MEDIUM)
• 1912 Design Movie Rental System (HARD)
• 1913 Maximum Product Difference Between Two Pairs (EASY)
• 1914 Cyclically Rotating a Grid (MEDIUM)
• 1915 Number of Wonderful Substrings (MEDIUM)
• 1916 Count Ways to Build Rooms in an Ant Colony (HARD)
• 1918 Kth Smallest Subarray Sum (MEDIUM) PREMIUM ONLY
• 1920 Build Array from Permutation (EASY)
• 1921 Eliminate Maximum Number of Monsters (MEDIUM)
• 1922 Count Good Numbers (MEDIUM)
• 1923 Longest Common Subpath (HARD)
• 1924 Erect the Fence II (HARD) PREMIUM ONLY
• 1925 Count Square Sum Triples (EASY)
• 1926 Nearest Exit from Entrance in Maze (MEDIUM)
• 1927 Sum Game (MEDIUM)
• 1928 Minimum Cost to Reach Destination in Time (HARD)
• 1929 Concatenation of Array (EASY)
• 1930 Unique Length-3 Palindromic Subsequences (MEDIUM)
• 1931 Painting a Grid With Three Different Colors (HARD)
• 1932 Merge BSTs to Create Single BST (HARD)
• 1933 Check if String Is Decomposable Into Value-Equal Substrings (EASY) PREMIUM ONLY
• 1935 Maximum Number of Words You Can Type (EASY)
• 1936 Add Minimum Number of Rungs (MEDIUM)
• 1937 Maximum Number of Points with Cost (MEDIUM)
• 1938 Maximum Genetic Difference Query (HARD)
• 1940 Longest Common Subsequence Between Sorted Arrays (MEDIUM) PREMIUM ONLY
• 1941 Check if All Characters Have Equal Number of Occurrences (EASY)
• 1942 The Number of the Smallest Unoccupied Chair (MEDIUM)
• 1943 Describe the Painting (MEDIUM)
• 1944 Number of Visible People in a Queue (HARD)
• 1945 Sum of Digits of String After Convert (EASY)
• 1946 Largest Number After Mutating Substring (MEDIUM)
• 1947 Maximum Compatibility Score Sum (MEDIUM)
• 1948 Delete Duplicate Folders in System (HARD)
• 1950 Maximum of Minimum Values in All Subarrays (MEDIUM) PREMIUM ONLY
• 1952 Three Divisors (EASY)
• 1953 Maximum Number of Weeks for Which You Can Work (MEDIUM)
• 1954 Minimum Garden Perimeter to Collect Enough Apples (MEDIUM)
• 1955 Count Number of Special Subsequences (HARD)
• 1956 Minimum Time For K Virus Variants to Spread (HARD) PREMIUM ONLY
• 1957 Delete Characters to Make Fancy String (EASY)
• 1958 Check if Move is Legal (MEDIUM)
• 1959 Minimum Total Space Wasted With K Resizing Operations (MEDIUM)
• 1960 Maximum Product of the Length of Two Palindromic Substrings (HARD)
• 1961 Check If String Is a Prefix of Array (EASY)
• 1962 Remove Stones to Minimize the Total (MEDIUM)
• 1963 Minimum Number of Swaps to Make the String Balanced (MEDIUM)
• 1964 Find the Longest Valid Obstacle Course at Each Position (HARD)
• 1966 Binary Searchable Numbers in an Unsorted Array (MEDIUM) PREMIUM ONLY
• 1967 Number of Strings That Appear as Substrings in Word (EASY)
• 1968 Array With Elements Not Equal to Average of Neighbors (MEDIUM)
• 1969 Minimum Non-Zero Product of the Array Elements (MEDIUM)
• 1970 Last Day Where You Can Still Cross (HARD)
• 1971 Find if Path Exists in Graph (EASY)
• 1973 Count Nodes Equal to Sum of Descendants (MEDIUM) PREMIUM ONLY
• 1974 Minimum Time to Type Word Using Special Typewriter (EASY)
• 1975 Maximum Matrix Sum (MEDIUM)
• 1976 Number of Ways to Arrive at Destination (MEDIUM)
• 1977 Number of Ways to Separate Numbers (HARD)
• 1979 Find Greatest Common Divisor of Array (EASY)
• 1980 Find Unique Binary String (MEDIUM)
• 1981 Minimize the Difference Between Target and Chosen Elements (MEDIUM)
• 1982 Find Array Given Subset Sums (HARD)
• 1983 Widest Pair of Indices With Equal Range Sum (MEDIUM) PREMIUM ONLY
• 1984 Minimum Difference Between Highest and Lowest of K Scores (EASY)
• 1985 Find the Kth Largest Integer in the Array (MEDIUM)
• 1986 Minimum Number of Work Sessions to Finish the Tasks (MEDIUM)
• 1987 Number of Unique Good Subsequences (HARD)
• 1989 Maximum Number of People That Can Be Caught in Tag (MEDIUM) PREMIUM ONLY
• 1991 Find the Middle Index in Array (EASY)
• 1992 Find All Groups of Farmland (MEDIUM)
• 1993 Operations on Tree (MEDIUM)
• 1994 The Number of Good Subsets (HARD)
• 1995 Count Special Quadruplets (EASY)
• 1996 The Number of Weak Characters in the Game (MEDIUM)
• 1997 First Day Where You Have Been in All the Rooms (MEDIUM)
• 1998 GCD Sort of an Array (HARD)
• 1999 Smallest Greater Multiple Made of Two Digits (MEDIUM) PREMIUM ONLY
• 2000 Reverse Prefix of Word (EASY)
• 2001 Number of Pairs of Interchangeable Rectangles (MEDIUM)
• 2002 Maximum Product of the Length of Two Palindromic Subsequences (MEDIUM)
• 2003 Smallest Missing Genetic Value in Each Subtree (HARD)
• 2005 Subtree Removal Game with Fibonacci Tree (HARD) PREMIUM ONLY
• 2006 Count Number of Pairs With Absolute Difference K (EASY)
• 2007 Find Original Array From Doubled Array (MEDIUM)
• 2008 Maximum Earnings From Taxi (MEDIUM)
• 2009 Minimum Number of Operations to Make Array Continuous (HARD)
• 2011 Final Value of Variable After Performing Operations (EASY)
• 2012 Sum of Beauty in the Array (MEDIUM)
• 2013 Detect Squares (MEDIUM)
• 2014 Longest Subsequence Repeated k Times (HARD)