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…

207. Course Schedule Problem's Link ---------------------------------------------------------------------------- Mean: 给定一个有向图,判断是否存在top_sort序列. analyse: 转换为:判断是否存在环. 若存在环,肯定不能找到top_sort序列. 判环的方式有很多:SPFA,top_sort,BFS,DFS...随便选一种就行. Time complexity: O…

https://blog.csdn.net/wongleetion/article/details/79433101 问题的实质就是判断一个有向图是否有环,利用入度去解决这个问题 使用bfs解决问题. 初始化时,利用二维vector存储节点间的关系,并存储每个节点的入度,同时将入度为0的节点放入队列,这是图的起始点. 每次将队列中的节点弹出后,然后将对应的课程的入度减少,如果有此时产生入度为0的节点,再加入队列中,直到队列为空. 最终判断整个入度的存储是否还有节点入度不为0. class Sol…

lc 207 Course Schedule 207 Course Schedule 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…

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 lis…

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…

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…

Course Schedule 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…

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 lis…

Problem Description In graph theory, the complement of a graph G is a graph H on the same vertices such that two distinct vertices of H are adjacent if and only if they are not adjacent in G. Now you are given an undirected graph G of N nodes and M b…