LeetCode 327. Count of Range Sum
Description https://leetcode.com/problems/count-of-range-sum/ Given an integer array nums and two integers lower and upper, return the number of range sums that lie in [lower, upper] inclusive. Range sum S(i, j) is…
LeetCode 10. Regular Expression Matching
Description https://leetcode.com/problems/regular-expression-matching/ Given an input string s and a pattern p, implement regular expression matching with support for ‘.’ and ‘*’ where: ‘.’ Matches any single character. ‘*’ Matches…
LeetCode 305. Number of Islands II
Description https://leetcode.com/problems/number-of-islands-ii/ You are given an empty 2D binary grid grid of size m x n. The grid represents a map where 0‘s represent…
LeetCode 526. Beautiful Arrangement
Description https://leetcode.com/problems/beautiful-arrangement/ Suppose you have n integers labeled 1 through n. A permutation of those n integers perm (1-indexed) is considered a beautiful arrangement if for every i (1 <= i <= n), either of…
LeetCode 289. Game of Life
Description https://leetcode.com/problems/game-of-life/ According to Wikipedia’s article: “The Game of Life, also known simply as Life, is a cellular automaton devised by the British…
LeetCode 800. Similar RGB Color
Description https://leetcode.com/problems/similar-rgb-color/ The red-green-blue color “#AABBCC” can be written as “#ABC” in shorthand. For example, “#15c” is shorthand for the color “#1155cc”. The similarity between the two…
LeetCode 293. Flip Game
Description https://leetcode.com/problems/flip-game/ You are playing a Flip Game with your friend. You are given a string currentState that contains only ‘+’ and ‘-‘. You and…
LeetCode 422. Valid Word Square
Description https://leetcode.com/problems/valid-word-square/ Given an array of strings words, return true if it forms a valid word square. A sequence of strings forms a valid word…
LeetCode 567. Permutation in String
Description https://leetcode.com/problems/permutation-in-string/ Given two strings s1 and s2, return true if s2 contains a permutation of s1, or false otherwise. In other words, return true if one of s1‘s permutations is the substring…
LeetCode 301. Remove Invalid Parentheses
Description https://leetcode.com/problems/remove-invalid-parentheses/ Given a string s that contains parentheses and letters, remove the minimum number of invalid parentheses to make the input…