You are climbing a stair case. It takes n steps to reach to the top. Each time you can either climb …

  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…

按奇偶排序数组 II【简单】 给定一个非负整数数组 A， A 中一半整数是奇数，一半整数是偶数。 对数组进行排序，以便当 A[i] 为奇数时，i 也是奇数；当 A[i] 为偶数时， i 也是偶数。 你可以返回任何满足上述…

  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…

The thief has found himself a new place for his thievery again. There is only one entrance to this area, calle…