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Given an input string (s) and a pattern (p), implement wildcard pattern matching with support for '?' and '*'.'?' Matches any single character.'*' Matches any sequence of characters (including the e...

Given two words (beginWord and endWord), and a dictionary’s word list, find all shortest transformation sequence(s) from beginWord to endWord, such that:Only one letter can be changed at a timeEach...

Given an integer n, generate all structurally unique BST’s (binary search trees) that store values 1 … n.Example:Input: 3Output:[ [1,null,3,2], [3,2,null,1], [3,1,null,null,2], [2,1,3], ...

A Range Module is a module that tracks ranges of numbers. Your task is to design and implement the following interfaces in an efficient manner.addRange(int left, int right) Adds the half-open interva...

Given a binary tree, find the length of the longest path where each node in the path has the same value. This path may or may not pass through the root.Note: The length of path between two nodes is r...

Given an integer array, return the k-th smallest distance among all the pairs. The distance of a pair (A, B) is defined as the absolute difference between A and B.Example 1:Input:nums = [1,3,1]k =...

Given a complete binary tree, count the number of nodes.Note:Definition of a complete binary tree from Wikipedia:In a complete binary tree every level, except possibly the last, is completely fille...

Given an unsorted integer array, find the smallest missing positive integer.Example 1:Input: [1,2,0]Output: 3Example 2:Input: [3,4,-1,1]Output: 2Example 3:Input: [7,8,9,11,12]Output: 1Not...

Given an array of integers A, consider all non-empty subsequences of A.For any sequence S, let the width of S be the difference between the maximum and minimum element of S.Return the sum of the wid...

A robot on an infinite grid starts at point (0, 0) and faces north. The robot can receive one of three possible types of commands:-2: turn left 90 degrees-1: turn right 90 degrees1 <= x <= ...

Given a string s, find the longest palindromic substring in s. You may assume that the maximum length of s is 1000.Example 1:Input: "babad"Output: "bab"Note: "aba" is also a valid answer.Example...

Given n balloons, indexed from 0 to n-1. Each balloon is painted with a number on it represented by array nums. You are asked to burst all the balloons. If the you burst balloon i you will get nums[le...

In this problem, a rooted tree is a directed graph such that, there is exactly one node (the root) for which all other nodes are descendants of this node, plus every node has exactly one parent, excep...

There are two sorted arrays nums1 and nums2 of size m and n respectively.Find the median of the two sorted arrays. The overall run time complexity should be O(log (m+n)).You may assume nums1 and num...