Next Permutation Implement next permutation, which rearranges numbers into the lexicographically next greater …

Delete Node in a Linked List Write a function to delete a node (except the tail) in a singly linked list, give…

1. 题目 Given a roman numeral, convert it to an integer. Input is guaranteed to be within the range from 1 to 39…

  A gene string can be represented by an 8-character long string, with choices from "A", "C",&n…

题目描述 You are a professional robber planning to rob houses along a street. Each house has a certain amount of m…

Given a complete binary tree, count the number of nodes. Note:Definition of a complete binary tree from Wikipe…

Rotate Image You are given an n x n 2D matrix representing an image. Rotate the image by 90 degrees (clockwise…

1. 题目 Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses. …

题目地址：https://leetcode-cn.com/probl…题目描述：给定一组不含重复元素的整数数组 nums，返回该数组所有可能的子集（幂集）。 说明：解集不能包含重复的子集。 示例: 输入: n…

  Given a binary tree, return all duplicate subtrees. For each kind of duplicate subtrees, you only need …

题目： Given a binary tree struct TreeLinkNode { TreeLinkNode *left; TreeLinkNode *right; TreeLinkNode *next; } P…

Perfect Squares Given a positive integer n, find the least number of perfect square numbers (for example, 1, 4…