Problem The n-queens puzzle is the problem of placing n queens on an n x n chessboard such that no two queens attack each other. Given an integer n, return all distinct solutions to the n-queens puzzle. You may return the answer in any order. Each solution contains a distinct board configuration of the n-queens’ placement, where 'Q' and '.' both indicate a queen and an empty space, respectively. ...
Problem Given an array of integers of size n, print or return all the subsets of size k. (k<=n) Examples Example 1: Input: nums = [1, 2, 3, 4, 5], k = 3 Output: [ [1 2 3], [1 2 4], [1 2 5] [1 3 4], [1 3 5], [1 4 5], [2 3 4], [2 3 5], [2 4 5], [3 4 5] ] ...
Problem There is a robot on an m x n grid. The robot is initially located at the top-left corner (i.e., grid[0][0]). The robot tries to move to the bottom-right corner (i.e., grid[m - 1][n - 1]). The robot can only move either down or right at any point in time. Given the two integers m and n, return all possible unique paths that the robot can take to reach the bottom-right corner. ...
Problem Given a string s, partition s such that every substring of the partition is a palindrome. Return all possible palindrome partitioning of s. Definition Palindrome Definition Examples Example 1: Input: s = "aab" Output: [ ["a","a","b"],["aa","b"] ] Example 2: Input: s = "a" Output: [ ["a"] ] ...
Problem Given a set of distinct integers/characters, S, return all possible subsets. OR Given an integer array nums of unique elements, return all possible subsets (the power set). Examples If we’re given a set of integers such that S = {1, 2, 3}, how can we find all the subsets of that set? For example, given S, the set of all subsets i.e. P(S) we get are {}, {1}, {2}, {3}, {1, 2}, {1, 3}, {2, 3}, and {1, 2, 3}. Here is {} is empty set denoted by Φ. ...
Problem An image is represented by an m x n integer grid image where image[i][j] represents the pixel value of the image. You are also given three integers sr, sc, and color. You should perform a flood fill on the image starting from the pixel image[sr][sc]. To perform a flood fill, consider the starting pixel, plus any pixels connected 4-directionally to the starting pixel of the same color as the starting pixel, plus any pixels connected 4-directionally to those pixels (also with the same color), and so on. Replace the color of all of the aforementioned pixels with color. ...
Problem Find all valid combinations of k numbers that sum up to n such that the following conditions are true: Only numbers 1 through 9 are used. Each number is used at most once. Return a list of all possible valid combinations. The list must not contain the same combination twice, and the combinations may be returned in any order. Examples Example 1: Input: k = 3, n = 7 Output: [ [1,2,4] ] Explanation: 1 + 2 + 4 = 7 There are no other valid combinations. ...
Problem Given a string s and a dictionary of words dict, determine if s can be segmented into a space-separated sequence of one or more dictionary words. Examples Example 1: Input: s = "leetcode", wordDict = ["leet","code"] Output: true Explanation: Return true because "leetcode" can be segmented as "leet code". Example 2: ...
Problem Given a binary tree and a sum, find all root-to-leaf paths where each path’s sum equals the given sum. Examples Example 1: graph TD; A[5] --> B[4] & C[8] B --> D[11] & E[null] C --> F[13] & G[4] D --> H[7] & I[2] G --> L[5] & M[1] style A fill:#f9f style B fill:#f9f style C fill:#f9f style D fill:#f9f style I fill:#f9f style G fill:#f9f style L fill:#f9f ...
Problem Given an integer array nums that may contain duplicates, return all possible subsets (the power set). The solution set must not contain duplicate subsets. Return the solution in any order. Examples Example 1: Input: nums = [1,2,2] Output: [ [],[1],[1,2],[1,2,2],[2],[2,2] ] Example 2: Input: nums = [0] Output: [ [],[0] ] ...