Description: Given a positive integer n, find the least number of perfect square numbers (for example, 1, 4, 9…

题目： You are given two linked lists representing two non-negative numbers. The digits are stored in reverse ord…

题目描述 Given a positive integer n, find the least number of perfect square numbers (for example, 1, 4, 9, 16, …)…

Group Anagrams 最新更新请见：https://yanjia.me/zh/2019/01/… Given an array of strings, group anagrams together.…

Valid Roman Numeral 正则表达式 思路 首先我们要熟悉罗马数的表达方式。M是1000，D是500，C是100，L是50，X是10，V是5，I是1。验证字符串是否是罗马数，我们先看一下有效的罗马数是什么样…

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

Kth Largest Element in an Array Find the kth largest element in an unsorted array. Note that it is the kth lar…

1. 题目 Implement regular expression matching with support for ‘.’ and ‘*’. ‘.R…

Follow up for “Remove Duplicates”: What if duplicates are allowed at most twice? For example,…

1 题目描述 Given an array of non-negative integers, you are initially positioned at the first index of the array. …

209. 长度最小的子数组 问题 给定一个含有 个正整数的数组和一个正整数 ，找出该数组中满足其和 的长度最小的连续子数组。如果不存在符合条件的连续子数组，返回。 示例: 输入: 输出: 解释: 子数组 是该条件下的长度…

Problem Given an array of integers that is already sorted in ascending order, find two numbers such that they …