1. 题目 Given a m x n matrix, if an element is 0, set its entire row and column to 0. Do it in place. 对matrixi==…

Follow up for problem “Populating Next Right Pointers in Each Node“. What if the given tree could …

题目： Given a collection of intervals, merge all overlapping intervals. For example, Given [1,3],[2,6],[8,10],[1…

描述： Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the v…

Medium 思路参考House Rubbery和Gas station，之前我纠结重复的数字怎么处理，结果很简单。维持一个数组，以num为index，值为该num拥有的总points数。多次遇到就多次加就好了。 cla…

题目分析 这个题目的题眼在于状态转换的比较多. 我认为最好的一种解法是使用了三个一维DP数组维护状态. buy_dp sell_dp cool_dp 使用了三个一维DP数组的好处 空间换复杂度, 更多的空间, 可以使我们…

题目 Given a sorted array, remove the duplicates in place such that each element appear only once and return the…

  The count-and-say sequence is the sequence of integers beginning as follows:1, 11, 21, 1211, 111221, ..…

  Given a non-empty special binary tree consisting of nodes with the non-negative value, where each node …

  S and T are strings composed of lowercase letters. In S, no letter occurs more than…

题目地址：https://leetcode-cn.com/probl…题目描述：在上次打劫完一条街道之后和一圈房屋后，小偷又发现了一个新的可行窃的地区。这个地区只有一个入口，我们称之为“根”。 除了“根”之外…

其思路类似于3sum。下面是题目和代码。 Given an array S of n integers, are there elements a, b, c, and d in S such that a + b + …