Detect Cycle in a Directed Graph 推断一个图是否有环,有环图例如以下: 这里唯一注意的就是,这是个有向图, 边组成一个环,不一定成环,由于方向能够不一致. 这里就是添加一个数组保存当前已经訪问过的路径信息 recStack[]: 而visited[]数组是訪问过的点的信息,两者作用是不一样的. 知道这个知识点,这道题就非常easy了. 原文: http://www.geeksforgeeks.org/detect-cycle-in-a-graph/ #includ…

Question: Detect cycle in a directed graph Answer: Depth First Traversal can be used to detect cycle in a Graph. DFS for a connected graph produces a tree. There is a cycle in a graph only if there is a back edge present in the graph. A back edge is…

geeks上的解答复杂了些,用回溯就行了 #include <iostream> #include <vector> #include <algorithm> #include <queue> #include <stack> #include <string> #include <fstream> using namespace std; ; vector<int> trace; vector<bool…

Given n nodes labeled from 0 to n - 1 and a list of undirected edges (each edge is a pair of nodes), write a function to check whether these edges make up a valid tree. For example: Given n = 5 and edges = [[0, 1], [0, 2], [0, 3], [1, 4]], return tru…

Given a Directed Graph and two vertices in it, check whether there is a path from the first given vertex to second. For example, in the following graph, there is a path from vertex 1 to 3. As another example, there is no path from 3 to 0. We can eith…

Counting on a directed graph Problem Code: GRAPHCNT All submissions for this problem are available. Read problems statements in Mandarin Chineseand Russian. Given an directed graph with N nodes (numbered from 1 to N) and M edges, calculate the number…

4.2 Given a directed graph, design an algorithm to find out whether there is a route between two nodes. LeetCode和CareerCup中关于图的题都不是很多,LeetCode中只有三道,分别是Clone Graph 无向图的复制,Course Schedule 课程清单 和 Course Schedule II 课程清单之二.目前看来CareerCup中有关图的题在第四章中仅此一道,这是…

  Find the number Weak Connected Component in the directed graph. Each node in the graph contains a label and a list of its neighbors. (a connected set of a directed graph is a subgraph in which any two vertices are connected by direct edge path.) Ex…

这里总结针对一个并不一定所有点都连通的general directed graph, 去判断graph里面是否有loop存在, 收到启发是因为做了[LeetCode] 207 Course Schedule_Medium tag: BFS, DFS, 这个题实际上就是监测directed graph里面是否有loop存在. 我在网上看了比较经典的做法为DFS, 并且用三个set去标志not visited点,(0), 正在visiting的点(-1), 已经visited过的点(1), 我结合这…

Skeleton-Based Action Recognition with Directed Graph Neural Network 摘要 因为骨架信息可以鲁棒地适应动态环境和复杂的背景,所以经常被广泛应用在动作识别任务上,现有的方法已经证实骨架中的关键点和骨头信息对动作识别任务非常有用.然而如何将两种类型的数据最大化地利用还没有被很好地解决. 作者将骨架数据表示成一个有向非循环图(Directed acyclic graph),该图基于自然人体的节点和骨骼的动力学依赖. 这个新颖的图结构用…

Description Find the number Weak Connected Component in the directed graph. Each node in the graph contains a label and a list of its neighbors. (a weak connected component of a directed graph is a maximum subgraph in which any two vertices are conne…

/// the original blog is http://www.cnblogs.com/tmzbot/p/5579020.html , automatic crawling without link to original blog is unallowed. 判定 + 寻找一组解 (感觉这个东西挺有意思的记录一下..) /// the original blog is http://www.cnblogs.com/tmzbot/p/5579020.html , automatic cr…

#include<iostream> #include<cstdio> #include<cstring> #include<limits> #include<vector> using namespace std; ; struct edge{ int to, cost; edge(int t){ ; } }; void addEdge(vector<edge> &edgelist, vector<vector<…

1 深度优先方法 首先需要更改矩阵初始化函数init_graph() 然后我们需要初始化vist标记数组 深度优先访问图,然后根据是否存在back edge判断是否存在环路 算法如下: #include <iostream> using namespace std; #define MAX_VERTEX_NUM 128 enum color{WHITE, GRAY = 1, BLACK}; bool M[MAX_VERTEX_NUM][MAX_VERTEX_NUM]; int colour[M…

package leetcode; public class DetectCycle { public ListNode detectCycle(ListNode head) { ListNode s=head; ListNode f=head; while(f!=null&&f.next!=null){ s=s.next; f=f.next.next; if(s==f){ break; } } if(f==null||f.next==null) return null; s=head;…

https://www.microsoft.com/en-us/research/product/cognitive-toolkit/ https://github.com/microsoft/cntk https://github.com/Microsoft/CNTK/blob/master/README.md…

闲下来后,需要讲最近涉及到的算法全部整理一下,有个indice,方便记忆宫殿的查找 MIT的算法课,地球上最好:https://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-046j-design-and-analysis-of-algorithms-spring-2015/lecture-notes/ Why Puzzles? Solving puzzles will help you sharpen you…

闲下来后,需要讲最近涉及到的算法全部整理一下,有个indice,方便记忆宫殿的查找 MIT的算法课,地球上最好: Design and Analysis of Algorithms 本篇需要重新整理,按照以下归类去理解”思想“,而非”算法细节“. 找到解决问题的”思维突破口“. “贪心算法” 算是 "动态规划" 的前置课程. 在数据结构graph中的优化问题也大量涉及到了”Greedy Method". 也有五大常用算法之说:算法设计之五大常用算法设计方法总结 一.[分治法]…

        F. Graph Without Long Directed Paths time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output You are given a connected undirected graph consisting of nn vertices and mm edges. There are no…

F. Graph Without Long Directed Paths time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output You are given a connected undirected graph consisting of nn vertices and mm edges. There are no self-lo…

You are given a connected undirected graph consisting of nn vertices and mm edges. There are no self-loops or multiple edges in the given graph. You have to direct its edges in such a way that the obtained directed graph does not contain any paths of…

Problem: Given n nodes labeled from 0 to n - 1 and a list of undirected edges (each edge is a pair of nodes), write a function to check whether these edges make up a valid tree. For example: Given n = 5 and edges = [[0, 1], [0, 2], [0, 3], [1, 4]], r…

Problem G: Going in Cycle!! Input: standard input Output: standard output You are given a weighted directed graph with n vertices and m edges. Each cycle in the graph has a weight, which equals to sum of its edges. There are so many cycles in the gra…

Problem  UVA - 11090 - Going in Cycle!! Time Limit: 3000 mSec Problem Description You are given a weighted directed graph with n vertices and m edges. Each cycle in the graph has a weight, which equals to sum of its edges. There are so many cycles in…

A tournament is a directed graph without self-loops in which every pair of vertexes is connected by exactly one directed edge. That is, for any two vertexes u and v (u ≠ v) exists either an edge going from u to v, or an edge from v to u. You are give…

There are a total of n courses you have to take, labeled from 0 to n - 1. Some courses may have prerequisites, for example to take course 0 you have to first take course 1, which is expressed as a pair: [0,1] Given the total number of courses and a l…

描述 Given a directed graph containing n vertice (numbered from 1 to n) and m edges. Can you tell us how many different Hamiltonian Cycles are there in this graph? A Hamiltonian Cycle is a cycle that starts from some vertex, visits each vertex (except…

Description You are given a directed graph consisting of \(n\) vertices and \(m\) edges (each edge is directed, so it can be traversed in only one direction). You are allowed to remove at most one edge from it. Can you make this graph acyclic by remo…

题目链接:http://codeforces.com/problemset/problem/117/C C. Cycle time limit per test 2.5 seconds memory limit per test 256 megabytes input standard input output standard output A tournament is a directed graph without self-loops in which every pair of ve…

D. Going in Cycle!! Time Limit: 3000ms Memory Limit: 131072KB 64-bit integer IO format: %lld      Java class name: Main   You are given a weighted directed graph with n vertices and m edges. Each cycle in the graph has a weight, which equals to sum o…