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Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases.For example,"A man, a plan, a canal: Panama" is a palindrome."race a car" is no

Given a collection of numbers, return all possible permutations.For example,[1,2,3] have the following permutations:[1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], and [3,2,1].void DFS(vect

Implement wildcard pattern matching with support for '?' and '*'.'?' Matches any single character.'*' Matches any sequence of characters (including the empty sequence).The matching should cover t

Given two binary strings, return their sum (also a binary string).For example,a = "11"b = "1"Return "100"class Solution {public: string addBinary(string a, string b) { // Start

Follow up for "Unique Paths":Now consider if some obstacles are added to the grids. How many unique paths would there be?An obstacle and empty space is marked as 1 and 0 respectively in the

Given a collection of numbers that might contain duplicates, return all possible unique permutations.For example,[1,1,2] have the following unique permutations:[1,1,2], [1,2,1], and [2,1,1

Given an array of non-negative integers, you are initially positioned at the first index of the array.Each element in the array represents your maximum jump length at that position.Your goal i

Given a string s consists of upper/lower-case alphabets and empty space characters ' ', return the length of last word in the string.If the last word does not exist, return 0.Note: A word is

Given an array of non-negative integers, you are initially positioned at the first index of the array.Each element in the array represents your maximum jump length at that position.Determine i

Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it is able to trap after raining.For example, Given [0,1,0,2,1,0,1,3,2,1,2,

Given a collection of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T.Each number in C may only be used once in the c

The set [1,2,3,…,n] contains a total of n! unique permutations.By listing and labeling all of the permutations in order,We get the following sequence (ie, for n = 3):"123""132""213"

Given a set of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T.The same repeated number may be chosen from C unlimited

Given a binary tree, determine if it is a valid binary search tree (BST).Assume a BST is defined as follows:The left subtree of a node contains only nodes with keys less than the node's key.

A robot is located at the top-left corner of a m x n grid (marked 'Start' in the diagram below).The robot can only move either down or right at any point in time. The robot is trying to reach th

You are given an n x n 2D matrix representing an image.Rotate the image by 90 degrees (clockwise).Follow up:Could you do this in-place?class Solution {public: void rotate(vector >

Given a number represented as an array of digits, plus one to the number.class Solution {public: vector plusOne(vector &arr) { // Start typing your C/C++ solution below // DO NO

Given a collection of integers that might contain duplicates, S, return all possible subsets.Note:Elements in a subset must be in non-descending order.The solution set must not contain d

Given a string containing only digits, restore it by returning all possible valid IP address combinations.For example:Given "25525511135",return ["255.255.11.135", "255.255.111.35"]. (Orde

Given s1, s2, s3, find whether s3 is formed by the interleaving of s1 and s2.For example,Given:s1 = "aabcc",s2 = "dbbca",When s3 = "aadbbcbcac", return true.When s3 = "aadbbbaccc",

Reverse a linked list from position m to n. Do it in-place and in one-pass.For example:Given 1->2->3->4->5->NULL, m = 2 and n = 4,return 1->4->3->2->5->NULL.Note:Given m, n satisfy

A message containing letters from A-Z is being encoded to numbers using the following mapping:'A' -> 1'B' -> 2...'Z' -> 26Given an encoded message containing digits, determine the total nu

Given n, how many structurally unique BST's (binary search trees) that store values 1...n?For example,Given n = 3, there are a total of 5 unique BST's. 1 3 3 2 1

Given two integers n and k, return all possible combinations of k numbers out of 1 ... n.For example,If n = 4 and k = 2, a solution is:[ [2,4], [3,4], [2,3], [1,2], [1,3], [1,4

The gray code is a binary numeral system where two successive values differ in only one bit.Given a non-negative integer n representing the total number of bits in the code, print the sequence of

Given a m x n matrix, if an element is 0, set its entire row and column to 0. Do it in place.class Solution {public: void setZeroes(vector > &matrix) { // Start typing your C/C++ solu

Given an absolute path for a file (Unix-style), simplify it.For example,path = "/home/", => "/home"path = "/a/./b/../../c/", => "/c"Corner Cases:Did you consider the case w

Given an array with n objects colored red, white or blue, sort them so that objects of the same color are adjacent, with the colors in the order red, white and blue.Here, we will use the integer

Given two words word1 and word2, find the minimum number of steps required to convert word1 to word2. (each operation is counted as 1 step.)You have the following 3 operations permitted on a w

Implement int sqrt(int x).Compute and return the square root of x.class Solution {public: int sqrt(int x) { // Start typing your C/C++ solution below // DO NOT write i

Given an unsorted integer array, find the first missing positive integer.For example,Given [1,2,0] return 3,and [3,4,-1,1] return 2.Your algorithm should run in O(n) time and uses consta