Given a string containing only digits, restore it by returning all possible valid IP address combinations. For example:Given...

Write a program to find the n-th ugly number. Ugly numbers are positive numbers whose prime factors only include 2, 3, 5. For...

Given n, how many structurally unique BST’s (binary search trees) that store values 1…n? For example,Given n = 3, there are a...

Given a positive integer n, find the least number of perfect square numbers (for example, 1, 4, 9, 16, ...) which sum to n. F...

Given a 2D binary matrix filled with 0’s and 1’s, find the largest square containing only 1’s and return its area. For exampl...

Given a collection of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate nu...

Given an array with n objects colored red, white or blue, sort them so that objects of the same color are adjacent, with the ...

Given an array S of n integers, are there elements a, b, c, and d in S such that a + b + c + d = target? Find all unique qua...

Implement next permutation, which rearranges numbers into the lexicographically next greater permutation of numbers. If such ...

Given a collection of numbers that might contain duplicates, return all possible unique permutations. For example,[1,1,2] hav...