Follow up for "Unique Paths": Now consider if some obstacles are added to the grids. How many unique paths would there be? An obstacle and empty space is marked as 1 and 0 respectively in the grid. For example, There is one obstacle in the middl…

[LeetCode]113. Path Sum II 解题报告(Python) 标签(空格分隔): LeetCode 作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.me/ 题目地址:https://leetcode.com/problems/path-sum-ii/description/ 题目描述: Given a binary tree and a sum, find all root-to-leaf paths where each…

Minimum Path Sum Given a m x n grid filled with non-negative numbers, find a path from top left to bottom right which minimizes the sum of all numbers along its path. Note: You can only move either down or right at any point in time.   动态规划即可,与Unique…

Find the contiguous subarray within an array (containing at least one number) which has the largest product. For example, given the array [2,3,-2,4],the contiguous subarray [2,3] has the largest product = 6. 找数字连续最大乘积子序列. 思路:这个麻烦在有负数和0,我的方法,如果有0,一切都设…

Given a m x n grid filled with non-negative numbers, find a path from top left to bottom right which minimizes the sum of all numbers along its path. Note: You can only move either down or right at any point in time. 思路:由于只能向两个方向走,瞬间就没有了路线迂回的烦恼,题目的难度…

Given a m x n grid filled with non-negative numbers, find a path from top left to bottom right which minimizes the sum of all numbers along its path. Note: You can only move either down or right at any point in time. 思路: 这题不要想得太复杂,什么搜索策略什么贪心什么BFS DFS…

本文为大便一箩筐的原创内容,转载请注明出处,谢谢:http://www.cnblogs.com/dbylk/p/4048209.html 原题: Given n, generate all structurally unique BST's (binary search trees) that store values 1...n. For example,Given n = 3, your program should return all 5 unique BST's shown below…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 DFS + DFS BFS + DFS 日期 题目地址:https://leetcode.com/problems/path-sum-iii/#/description 题目描述 You are given a binary tree in which each node contains an integer value. Find the num…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.me/ 文章目录 题目描述 题目大意 解题方法 BFS DFS 日期 题目地址:https://leetcode.com/problems/path-sum-ii/description/ 题目描述 Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given…

Given n, how many structurally unique BST's (binary search trees) that store values 1...n? For example, given n = 3, there are a total of 5 unique BST's. 1         3     3      2      1     \       /     /      / \      \      3     2     1      1  …

题目简述: Given an absolute path for a file (Unix-style), simplify it. For example, path = "/home/", => "/home" path = "/a/./b/../../c/", => "/c" click to show corner cases. 解题思路: 很明显是压栈弹栈的过程,难点在特殊情况要考虑周全,corner c…

A robot is located at the top-left corner of a m x n grid (marked 'Start' in the diagram below). The robot can only move either down or right at any point in time. The robot is trying to reach the bottom-right corner of the grid (marked 'Finish' in t…

Unique Binary Search Trees Given n, how many structurally unique BST's (binary search trees) that store values 1...n? For example,Given n = 3, there are a total of 5 unique BST's. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 2 3   推导出递推公式即可: 对于1个元素来…

Unique Binary Search Trees II Given n, generate all structurally unique BST's (binary search trees) that store values 1...n. For example,Given n = 3, your program should return all 5 unique BST's shown below. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \…

Unique Paths II Total Accepted: 22828 Total Submissions: 81414My Submissions Follow up for "Unique Paths": Now consider if some obstacles are added to the grids. How many unique paths would there be? An obstacle and empty space is marked as 1 an…

Given n, generate all structurally unique BST's (binary search trees) that store values 1...n. For example,Given n = 3, your program should return all 5 unique BST's shown below. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 2 3 这次的题目要求是得到所有的树. 我的思路:…

Given a triangle, find the minimum path sum from top to bottom. Each step you may move to adjacent numbers on the row below. For example, given the following triangle [ [], [,4], [6,,7], [4,,8,3] ] The minimum path sum from top to bottom is 11 (i.e.,…

Given n, how many structurally unique BST's (binary search trees) that store values 1...n? For example,Given n = 3, there are a total of 5 unique BST's. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 2 3   思路: 遇到二叉树,多半是分为左右子树两个问题递归下去. 由序列[1,…,m]和[i+1,…

A robot is located at the top-left corner of a m x n grid (marked 'Start' in the diagram below). The robot can only move either down or right at any point in time. The robot is trying to reach the bottom-right corner of the grid (marked 'Finish' in t…

A robot is located at the top-left corner of a m x n grid (marked 'Start' in the diagram below). The robot can only move either down or right at any point in time. The robot is trying to reach the bottom-right corner of the grid (marked 'Finish' in t…

题目: Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the values along the path equals the given sum. For example:Given the below binary tree and sum = 22, 5 / \ 4 8 / / \ 11 13 4 / \ \ 7 2 1 return…

problem 437. Path Sum III 参考 1. Leetcode_437. Path Sum III; 完…

Path Sum II Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum. For example:Given the below binary tree and sum = 22, 5 / \ 4 8 / / \ 11 13 4 / \ / \ 7 2 5 1 return [ [5,4,11,2], [5,8,4,5] ] 这题是在Path…

这道题是LeetCode里的第929道题. 题目要求: 每封电子邮件都由一个本地名称和一个域名组成,以 @ 符号分隔. 例如,在 alice@leetcode.com中, alice 是本地名称,而 leetcode.com 是域名. 除了小写字母,这些电子邮件还可能包含 '.' 或 '+'. 如果在电子邮件地址的本地名称部分中的某些字符之间添加句点('.'),则发往那里的邮件将会转发到本地名称中没有点的同一地址.例如,"alice.z@leetcode.com" 和 "al…

题目如下: In a gold mine grid of size m * n, each cell in this mine has an integer representing the amount of gold in that cell, 0 if it is empty. Return the maximum amount of gold you can collect under the conditions: Every time you are located in a cel…

题目如下: In an infinite binary tree where every node has two children, the nodes are labelled in row order. In the odd numbered rows (ie., the first, third, fifth,...), the labelling is left to right, while in the even numbered rows (second, fourth, six…

作者: 负雪明烛 id: fuxuemingzhu 个人博客:http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 DFS 日期 题目地址:https://leetcode-cn.com/problems/path-sum-iv/ 题目描述 If the depth of a tree is smaller than 5, then this tree can be represented by a list of three-digits integers. Fo…

作者: 负雪明烛 id: fuxuemingzhu 个人博客:http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 排序+并查集 优先级队列 日期 题目地址:https://leetcode-cn.com/problems/path-with-maximum-minimum-value/ 题目描述 Given a matrix of integers A with R rows and C columns, find the maximum score of a p…

Implement strStr(). Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack. 思路: 注意,在for循环中条件有计算得到的负数时, 一定要把计算括起来转换为int, 否则会默认转换为uchar 负数就会被误认为是一个很大的数字. ; i < - ); ++i) 实现很常规: int strStr(string haystac…

Given a non-negative number represented as an array of digits, plus one to the number. The digits are stored such that the most significant digit is at the head of the list. 分析:思路是很清晰的,就是从数字最低位开始向上循环,如果是9就变成0,如果不是就直接当前位加1,返回.如果全都是9,就在最高位加一个1. 但是我写C++…