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 A message containing letters from A-Z can be encoded into numbers using the following mapping: 'A' -> 1 'B' -> 2 ... 'Z' -> 26 To decode an encoded message, all the digits must be grouped then mapped back into letters using the reverse of the mapping above (there may be multiple ways). For example, "11106" can be mapped into: ...
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] ] ...
Recover Binary Search Tree Problem Problem You are given the root of a binary search tree (BST), where the values of exactly two nodes of the tree were swapped by mistake. Recover the tree without changing its structure. Note: A solution using O(n) space is pretty straight forward. Could you devise a constant space solution? Example Example 1: Input: *1 / *3 \ 2 Output: *3 / *1 \ 2 ...
Problem Given two strings word1 and word2, return the minimum number of operations required to convert word1 to word2. You have the following three operations permitted on a word: Insert a character Delete a character Replace or substitute a character Examples Example 1: Input: word1 = "horse", word2 = "ros" Output: 3 Explanation: horse -> rorse (replace 'h' with 'r') rorse -> rose (remove 'r') rose -> ros (remove 'e') ...
Problem Follow up for Remove duplicates from Sorted Array I: What if duplicates are allowed at most twice? OR Given an integer array nums sorted in non-decreasing order, remove some duplicates in-place such that each unique element appears at most twice. The relative order of the elements should be kept the same. Since it is impossible to change the length of the array in some languages, you must instead have the result be placed in the first part of the array nums. More formally, if there are k elements after removing the duplicates, then the first k elements of nums should hold the final result. It does not matter what you leave beyond the first k elements. ...
Problem Given an array of words and a length L, format the text such that each line has exactly L characters and is fully (left and right) justified. OR Given an array of strings words and a width maxWidth, format the text such that each line has exactly maxWidth characters and is fully (left and right) justified. You should pack your words in a greedy approach; that is, pack as many words as you can in each line. Pad extra spaces ' ' when necessary so that each line has exactly maxWidth characters. ...
Problem You are given an m x n integer array grid. There is a robot 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. An obstacle and space are marked as 1 or 0 respectively in grid. A path that the robot takes cannot include any square that is an obstacle. ...
Problem Given an array of intervals where intervals[i] = [starti, endi], merge all overlapping intervals, and return an array of the non-overlapping intervals that cover all the intervals in the input. OR Given a list of intervals, merge all the overlapping intervals to produce a list that has only mutually exclusive intervals. Examples Example 1: Input: intervals = [1,3],[2,6],[8,10],[15,18], Output: [1,6],[8,10],[15,18]. ...