LeetCode 04xx
LeetCode problems 400–499
LeetCode 04xx
| # | Problem | Difficulty | Time | Notes |
|---|---|---|---|---|
| 400 | Nth Digit | 🟡 Medium | 1m 15s | The problem asks us to find the digit that appears at position n in… |
| 401 | Binary Watch | 🟢 Easy | 1m 17s | The problem describes a binary watch that uses LEDs to represent ti… |
| 402 | Remove K Digits | 🟡 Medium | 1m 26s | The problem gives us a numeric string num and an integer k. We must… |
| 403 | Frog Jump | 🔴 Hard | 1m 17s | The problem describes a frog trying to cross a river by jumping acr… |
| 404 | Sum of Left Leaves | 🟢 Easy | 1m 4s | The problem gives us the root node of a binary tree and asks us to … |
| 405 | Convert a Number to Hexadecimal | 🟢 Easy | 40s | The problem asks us to convert a given 32-bit integer num into its … |
| 406 | Queue Reconstruction by Height | 🟡 Medium | 1m 5s | This problem gives us a list of people where each person is represe… |
| 407 | Trapping Rain Water II | 🔴 Hard | 1m 22s | This problem is the two dimensional version of the classic "Trappin… |
| 408 | Valid Word Abbreviation | 🟢 Easy | 1m 26s | In this problem, we are given two strings: - word, the original ful… |
| 409 | Longest Palindrome | 🟢 Easy | 38s | The problem asks us to find the length of the longest palindrome th… |
| 410 | Split Array Largest Sum | 🔴 Hard | 1m 22s | The problem gives an integer array nums and an integer k. We must d… |
| 411 | Minimum Unique Word Abbreviation | 🔴 Hard | 1m 10s | This problem asks us to generate the shortest possible abbreviation… |
| 412 | Fizz Buzz | 🟢 Easy | 1m 27s | The problem asks us to generate a list of strings for all integers … |
| 413 | Arithmetic Slices | 🟡 Medium | 1m 24s | The problem asks us to count how many contiguous subarrays of lengt… |
| 414 | Third Maximum Number | 🟢 Easy | 1m 23s | The problem asks us to find the third distinct maximum number in an… |
| 415 | Add Strings | 🟢 Easy | 1m 10s | The problem asks us to add two non-negative integers where each int… |
| 416 | Partition Equal Subset Sum | 🟡 Medium | 1m 4s | The problem asks whether an array of positive integers can be divid… |
| 417 | Pacific Atlantic Water Flow | 🟡 Medium | 1m 24s | The problem gives us a rectangular grid called heights, where each … |
| 418 | Sentence Screen Fitting | 🟡 Medium | 1m 7s | The problem gives us a screen with a fixed number of rows and cols,… |
| 419 | Battleships in a Board | 🟡 Medium | 1m | This problem gives us a two dimensional grid where each cell contai… |
| 420 | Strong Password Checker | 🔴 Hard | 1m 21s | The problem asks us to determine the minimum number of operations r… |
| 421 | Maximum XOR of Two Numbers in an Array | 🟡 Medium | 1m 29s | The problem gives us an array of non-negative integers called nums.… |
| 422 | Valid Word Square | 🟢 Easy | 30s | The problem asks us to determine whether a given list of strings fo… |
| 423 | Reconstruct Original Digits from English | 🟡 Medium | 40s | The problem asks us to reconstruct digits from a jumbled string of … |
| 424 | Longest Repeating Character Replacement | 🟡 Medium | 1m 15s | The problem gives us a string s consisting only of uppercase Englis… |
| 425 | Word Squares | 🔴 Hard | 39s | The problem is asking us to generate all possible word squares from… |
| 426 | Convert Binary Search Tree to Sorted Doubly Linked List | 🟡 Medium | 1m 8s | The problem asks us to transform a Binary Search Tree, abbreviated … |
| 427 | Construct Quad Tree | 🟡 Medium | 1m 23s | The problem asks us to convert a binary matrix into a Quad-Tree rep… |
| 428 | Serialize and Deserialize N-ary Tree | 🔴 Hard | 1m 24s | LeetCode 428, LeetCode Serialize and Deserialize N-ary Tree, asks u… |
| 429 | N-ary Tree Level Order Traversal | 🟡 Medium | 40s | The problem asks us to perform a level order traversal of an n-ary … |
| 430 | Flatten a Multilevel Doubly Linked List | 🟡 Medium | 1m 24s | The problem gives us a special type of doubly linked list where eve… |
| 431 | Encode N-ary Tree to Binary Tree | 🔴 Hard | 1m 29s | This problem asks us to design a reversible transformation between … |
| 432 | All O`one Data Structure | 🔴 Hard | 1m 24s | The problem asks us to design a special data structure that stores … |
| 433 | Minimum Genetic Mutation | 🟡 Medium | 1m 34s | The problem describes a mutation process between genetic sequences.… |
| 434 | Number of Segments in a String | 🟢 Easy | 1m 1s | The problem asks us to count how many separate word-like groups exi… |
| 435 | Non-overlapping Intervals | 🟡 Medium | 1m 28s | The problem gives an array of intervals where each interval is repr… |
| 436 | Find Right Interval | 🟡 Medium | 44s | This problem asks us to find, for each interval in a list, the "rig… |
| 437 | Path Sum III | 🟡 Medium | 1m 11s | The problem gives us the root of a binary tree and an integer targe… |
| 438 | Find All Anagrams in a String | 🟡 Medium | 1m 21s | The problem gives two strings, s and p, both containing only lowerc… |
| 439 | Ternary Expression Parser | 🟡 Medium | 1m 16s | The problem gives us a string representing a nested ternary express… |
| 440 | K-th Smallest in Lexicographical Order | 🔴 Hard | 1m 19s | The problem asks us to find the k-th smallest number in lexicograph… |
| 441 | Arranging Coins | 🟢 Easy | 1m 9s | The problem asks us to determine how many complete rows of a coin s… |
| 442 | Find All Duplicates in an Array | 🟡 Medium | 1m 10s | The problem gives us an integer array nums of length n, where every… |
| 443 | String Compression | 🟡 Medium | 1m 4s | The problem asks us to perform in place string compression on an ar… |
| 444 | Sequence Reconstruction | 🟡 Medium | 1m 21s | This problem asks us to determine whether the given array nums is b… |
| 445 | Add Two Numbers II | 🟡 Medium | 1m 12s | The problem gives us two non-empty singly linked lists where each n… |
| 446 | Arithmetic Slices II - Subsequence | 🔴 Hard | 1m 20s | The problem asks us to count how many arithmetic subsequences exist… |
| 447 | Number of Boomerangs | 🟡 Medium | 1m 20s | The problem asks us to count the number of valid boomerangs among a… |
| 448 | Find All Numbers Disappeared in an Array | 🟢 Easy | 54s | The problem asks us to find all the integers in the range [1, n] th… |
| 449 | Serialize and Deserialize BST | 🟡 Medium | 1m 8s | The problem asks us to design two operations for a Binary Search Tr… |
| 450 | Delete Node in a BST | 🟡 Medium | 1m 29s | The problem asks us to delete a node with a specific value, key, fr… |
| 451 | Sort Characters By Frequency | 🟡 Medium | 54s | The problem asks us to rearrange the characters of a string so that… |
| 452 | Minimum Number of Arrows to Burst Balloons | 🟡 Medium | 41s | This problem is asking us to determine the minimum number of vertic… |
| 453 | Minimum Moves to Equal Array Elements | 🟡 Medium | 44s | The problem gives an integer array nums with n elements. In a singl… |
| 454 | 4Sum II | 🟡 Medium | 1m 13s | The problem gives four integer arrays, nums1, nums2, nums3, and num… |
| 455 | Assign Cookies | 🟢 Easy | 48s | This problem asks us to maximize the number of children who can be … |
| 456 | 132 Pattern | 🟡 Medium | 1m 19s | The problem asks us to determine whether an array contains a specif… |
| 457 | Circular Array Loop | 🟡 Medium | 1m 25s | This problem asks us to determine whether a circular array contains… |
| 458 | Poor Pigs | 🔴 Hard | 57s | The problem gives us a set of buckets where exactly one bucket cont… |
| 459 | Repeated Substring Pattern | 🟢 Easy | 48s | The problem asks us to determine whether a given string can be form… |
| 460 | LFU Cache | 🔴 Hard | 1m 11s | The problem asks us to design a cache that supports two operations:… |
| 461 | Hamming Distance | 🟢 Easy | 46s | The problem asks us to compute the Hamming distance between two int… |
| 462 | Minimum Moves to Equal Array Elements II | 🟡 Medium | 53s | This problem asks us to determine the minimum number of moves requi… |
| 463 | Island Perimeter | 🟢 Easy | 32s | The problem asks us to calculate the perimeter of an island represe… |
| 464 | Can I Win | 🟡 Medium | 56s | This problem describes a two-player turn-based game. Players take t… |
| 465 | Optimal Account Balancing | 🔴 Hard | 1m 33s | The problem gives a list of money transfers between people. Each tr… |
| 466 | Count The Repetitions | 🔴 Hard | 34s | The problem asks us to find the maximum number of times a string st… |
| 467 | Unique Substrings in Wraparound String | 🟡 Medium | 1m 16s | The problem defines an infinite cyclic string built from the lowerc… |
| 468 | Validate IP Address | 🟡 Medium | 1m 19s | The problem asks us to determine whether a given string represents … |
| 469 | Convex Polygon | 🟡 Medium | 1m 6s | The problem gives us a sequence of points on a 2D plane. These poin… |
| 470 | Implement Rand10() Using Rand7() | 🟡 Medium | 1m 19s | The problem provides access to a single API, rand7(), which returns… |
| 471 | Encode String with Shortest Length | 🔴 Hard | 48s | Here’s a fully detailed technical solution guide following your req… |
| 472 | Concatenated Words | 🔴 Hard | 39s | The problem asks us to identify all words in a given list that can … |
| 473 | Matchsticks to Square | 🟡 Medium | 1m 15s | The problem gives us an array called matchsticks, where each elemen… |
| 474 | Ones and Zeroes | 🟡 Medium | 1m 13s | This problem asks us to select the largest possible subset of binar… |
| 475 | Heaters | 🟡 Medium | 54s | The problem gives two arrays, houses and heaters, where each value … |
| 476 | Number Complement | 🟢 Easy | 56s | The problem asks us to compute the complement of a positive integer… |
| 477 | Total Hamming Distance | 🟡 Medium | 1m 11s | The problem asks us to compute the total Hamming distance between e… |
| 478 | Generate Random Point in a Circle | 🟡 Medium | 1m 23s | This problem asks us to generate random points uniformly inside a c… |
| 479 | Largest Palindrome Product | 🔴 Hard | 1m 14s | The problem asks us to find the largest palindrome number that can … |
| 480 | Sliding Window Median | 🔴 Hard | 1m 32s | The problem asks us to compute the median for every contiguous suba… |
| 481 | Magical String | 🟡 Medium | 1m 26s | This problem defines a special infinite sequence called the magical… |
| 482 | License Key Formatting | 🟢 Easy | 1m 10s | The problem gives us a string s that represents a license key. The … |
| 483 | Smallest Good Base | 🔴 Hard | 57s | The problem is asking us to find the smallest integer k = 2 such th… |
| 484 | Find Permutation | 🟡 Medium | 1m 9s | The problem gives us a string s consisting only of the characters '… |
| 485 | Max Consecutive Ones | 🟢 Easy | 57s | The problem gives us a binary array named nums, where every element… |
| 486 | Predict the Winner | 🟡 Medium | 1m 9s | The problem describes a two-player game played on an integer array.… |
| 487 | Max Consecutive Ones II | 🟡 Medium | 1m | The problem gives us a binary array nums, where every element is ei… |
| 488 | Zuma Game | 🔴 Hard | 1m 24s | The problem models a recursive elimination game played on a row of … |
| 489 | Robot Room Cleaner | 🔴 Hard | 1m 7s | This problem is an interactive backtracking problem where we must c… |
| 490 | The Maze | 🟡 Medium | 1m 22s | This problem asks us to determine whether a rolling ball can stop e… |
| 491 | Non-decreasing Subsequences | 🟡 Medium | 2m 43s | The problem gives us an integer array nums and asks us to return ev… |
| 492 | Construct the Rectangle | 🟢 Easy | 43s | The problem gives us a single integer, area, which represents the a… |
| 493 | Reverse Pairs | 🔴 Hard | 59s | The problem asks us to count how many pairs of indices (i, j) satis… |
| 494 | Target Sum | 🟡 Medium | 1m 9s | The problem asks us to count how many different ways we can assign … |
| 495 | Teemo Attacking | 🟢 Easy | 34s | The problem asks us to calculate the total duration that Ashe is po… |
| 496 | Next Greater Element I | 🟢 Easy | 55s | The problem is asking us to find the next greater element for each … |
| 497 | Random Point in Non-overlapping Rectangles | 🟡 Medium | 32s | The problem asks us to randomly pick an integer point from a set of… |
| 498 | Diagonal Traverse | 🟡 Medium | 1m 30s | This problem asks us to traverse a matrix in a specific diagonal pa… |
| 499 | The Maze III | 🔴 Hard | 2m 15s | This problem extends the mechanics introduced in earlier Maze probl… |