题目链接:poj.org/problem?id=1273 题目: 题意:求最大流. 思路:测板子题,分别用Dinic和EK实现(我的板子跑得时间均为0ms). Dinic代码实现如下: #include <set> #include <map> #include <queue> #include <stack> #include <cmath> #include <bitset> #include <cstdio> #in…

POJ 1273给出M条边,N个点,求源点1到汇点N的最大流量. 本文主要就是附上dinic的模板,供以后参考. #include <iostream> #include <stdio.h> #include <algorithm> #include <queue> #include <string.h> /* POJ 1273 dinic算法模板 边是有向的,而且存在重边,且这里重边不是取MAX,而是累加和 */ using namespace…

http://poj.org/problem?id=1273 Description Every time it rains on Farmer John's fields, a pond forms over Bessie's favorite clover patch. This means that the clover is covered by water for awhile and takes quite a long time to regrow. Thus, Farmer Jo…

                                                         Drainage Ditches Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 69983   Accepted: 27151 Description Every time it rains on Farmer John's fields, a pond forms over Bessie's favorit…

Drainage Ditches Time Limit: 1000MS Memory Limit: 10000K Total Submissions: 65146 Accepted: 25112 Description Every time it rains on Farmer John's fields, a pond forms over Bessie's favorite clover patch. This means that the clover is covered by wate…

Description Every time it rains on Farmer John's fields, a pond forms over Bessie's favorite clover patch. This means that the clover is covered by water for awhile and takes quite a long time to regrow. Thus, Farmer John has built a set of drainage…

一.题面 Drainage Ditches 二.分析 网络流的裸题. 1 Edmonds-Karp算法 求解网络流其实就是一个不断找增广路,然后每次找到一条增广路后更新残余网络的一个过程. EK算法主要就是用bfs去找增广路,然后不断更新残余网络得到最终答案. 2 Dinic算法 对于Ford-Fulkerson和Edmonds-Karp算法,求解网络流都是一次次用DFS或者BFS,这其实是很费时的,Dinic相当于就是一次BFS然后DFS求解出多条增广路. 3 ISAP 三.AC代码 1 //…

A - Drainage Ditches Time Limit:1000MS     Memory Limit:32768KB     64bit IO Format:%I64d & %I64u   Description Every time it rains on Farmer John's fields, a pond forms over Bessie's favorite clover patch. This means that the clover is covered by wa…

Drainage Ditches Time Limit : 2000/1000ms (Java/Other)   Memory Limit : 65536/32768K (Java/Other) Total Submission(s) : 5   Accepted Submission(s) : 3 Font: Times New Roman | Verdana | Georgia Font Size: ← → Problem Description Every time it rains on…

这里只是用来存放模板,几乎没有讲解,要看讲解网上应该很多吧…… ek bfs不停寻找增广路到找不到为止,找到终点时用pre回溯,O(VE^2) #include<cstdio> #include<iostream> #include<cstring> #include<queue> #include<algorithm> using namespace std; const int INF = 0x3f3f3f3f; ; ][], pre[],…