Given a non-empty binary tree, return the average value of the nodes on each level in the form of an ar…

  A Tic-Tac-Toe board is given as a string array board. Return True if and only if it is possible to…

题目： Given a linked list, reverse the nodes of a linked list k at a time and return its modified list…

题目描述 Given a binary tree, find the lowest common ancestor (LCA) of two given nodes in the tree. According to t…

Find all possible combinations of k numbers that add up to a number n, given that only numbers from 1 to 9 can…

Given a roman numeral, convert it to an integer. Input is guaranteed to be within the range from 1 to 3999. 题目…

链接：https://leetcode.com/submissions/detail/136407355/ 难度：Easy 题目：104. Maximum Depth of Binary Tree Given a bin…

这是悦乐书的第301次更新，第320篇原创 01 看题和准备 今天介绍的是LeetCode算法题中Easy级别的第169题（顺位题号是709）。实现具有字符串参数str的函数ToLowerCase()：以小写形式返回相同…

题意：给你一个已排序的vector，要求吧vector转换成二叉搜索树，且该二叉搜索树是高度平衡树。 解题思路：使用递归的办法，中间的数就是根节点，左边的一半组成左子树，右边的一半组成右子树，然后对左半vector和右半…

My Submissions Total Accepted: 11811 Total Submissions: 25597 Difficulty: Easy Contributors: Admin Find the su…

题目 Given an array containing n distinct numbers taken from 0, 1, 2, …, n, find the one that is missing f…

问题形貌 考证回文字符串给定一个字符串，考证它是不是是回文串，只斟酌字母和数字字符，能够疏忽字母的大小写。 申明：本题中，我们将空字符串定义为有用的回文串。 示例 1: 输入: "A man, a plan, a can…