2016/5/19 17:39:07 拓扑排序,是对有向无环图(Directed Acylic Graph , DAG )进行的一种操作,这种操作是将DAG中的所有顶点排成一个线性序列,使得图中的任意一对顶点u,v满足如下条件: 若边(u,v)∈E(G),则在最终的线性序列中出现在v的前面 好了,说人话:拓扑排序的应用常常和AOV网相联系,在一个大型的工程中,某些项目不是独立于其他项目的,这意味着这种非独立的项目的完成必须依赖与其它项目的完成而完成,不妨记为u,v,则若边(u,v)∈E(G),代…

题目大意:给出n个点,m条关系,按关系的从小到大排序. 题目分析:拓扑排序的模板题,套模板. kahn算法: 伪代码: Kahn算法: 摘一段维基百科上关于Kahn算法的伪码描述: L← Empty list that will contain the sorted elements S ← Set of all nodes with no incoming edges while S is non-empty do     remove a node n from S     insert n…

本文链接:http://www.cnblogs.com/Ash-ly/p/5398586.html 题意: 假设有N个变量,还有M个二元组(u, v),分别表示变量u 小于 v.那么.所有变量从小到大排列起来应该是什么样子的呢?例如,有四个变量a,b,c,d,若a < b, c < b, d < c, 则这四个变量的排序可能是a < d < c < b;尽管还有其他可能,你只需要找出其中一个即可. 思路: 把每个变量看成一个点,“小于”看成一个边,则得到一个有向图.这样…

John有n个任务,但是有些任务需要在做完另外一些任务后才能做. 输入 输入有多组数据,每组数据第一行有两个整数1 <= n <= 100 和 m.n是任务个数(标记为1到n),m两个任务直接关系的数量.在此之后,有m行,每行有2个整数i和j,代表任务i必须在任务j之前完成.用n = m = 0结束整个输入. 输出 每一个数据对应一行n个整数,代表任务完成的顺序. 样例输入 5 4 1 2 2 3 1 3 1 5 0 0 样例输出 1 4 2 5 3分析:这就是一道模板题吧,用dfs版本处理比…

John has n tasks to do. Unfortunately, the tasks are not independent and the execution of one task is only possible if other tasks have already been executed. Input The input will consist of several instances of the problem. Each instance begins with…

Ordering Tasks John has n tasks to do. Unfortunately, the tasks are not independent and the execution of one task isonly possible if other tasks have already been executed.InputThe input will consist of several instances of the problem. Each instance…

1940. Ordering Tasks Constraints Time Limit: 1 secs, Memory Limit: 32 MB Description John has n tasks to do. Unfortunately, the tasks are not independent and the execution of one task is only possible if other tasks have already been executed. Input…

UVA.10305 Ordering Tasks 题意分析 详解请移步 算法学习 拓扑排序(TopSort) 拓扑排序的裸题 基本方法是,indegree表示入度表,vector存后继节点.在topsort函数中,制造一个辅助队列,首先从入度表中找到入度为0的点作起点,并且置入度为-1.接着依次处理队列中的节点,首先根据他们的后继,将其后继节点的入度依次减1,若其后继节点中的入度存在-1的,说明成环,则不存在拓扑排序.紧接着再从入度表中找到入度为0的节点,加入到队列中,直到队列空.当退出whil…

M - Ordering Tasks Time Limit:3000MS     Memory Limit:0KB     64bit IO Format:%lld & %llu Description John has n tasks to do. Unfortunately, the tasks are not independent and the execution of one task is only possible if other tasks have already been…

John has n tasks to do. Unfortunately, the tasks are not independent and the execution of one task is only possible if other tasks have already been executed. John有n件工作要做,不幸的是这些工作并不独立,而是某件工作需要在另一件已经执行完了以后才能执行. InputThe input will consist of several i…