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…

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 Drainage Ditches Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 62708   Accepted: 24150 Description Every time it rains on Farmer John's fields, a pond forms over Bessie's favorite clover patch. This means…

http://poj.org/problem? id=1273 Drainage Ditches Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 55235   Accepted: 21104 Description Every time it rains on Farmer John's fields, a pond forms over Bessie's favorite clover patch. This mean…

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…

Drainage Ditches 题目抽象:给你m条边u,v,c.   n个定点,源点1,汇点n.求最大流.  最好的入门题,各种算法都可以拿来练习 (1):  一般增广路算法  ford() #include <iostream> #include <cstdio> #include <cstring> #include <cmath> #include <algorithm> #include <string> #include…

Drainage Ditches Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 74480   Accepted: 28953 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…

Drainage Ditches Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 59176   Accepted: 22723 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…

链接 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 draina…

题目链接:http://poj.org/problem?id=1273 Time Limit: 1000MS Memory Limit: 10000K 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…

题目链接:http://poj.org/problem?id=1273 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…

Drainage Ditches Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 67823   Accepted: 26209 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…

Drainage Ditches Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 67387   Accepted: 26035 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…

题目链接:poj1273 Drainage Ditches 呜呜,今天自学网络流,看了EK算法,学的晕晕的,留个简单模板题来作纪念... #include<cstdio> #include<vector> #include<queue> #include<cstring> #include<set> #include<algorithm> #define CLR(a,b) memset((a),(b),sizeof((a))) usi…

dinic版本 感觉dinic算法好帅,比Edmonds-Karp算法不知高到哪里去了 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. Th…

Drainage Ditches Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 63924   Accepted: 24673 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…

一.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 drainag…

就是普通的网络流问题,想试试新学的dinic算法,这个算法暑假就开始看国家集训队论文了,之前一直都只用没效率的EK算法,真正学会这个算法还是开学后白书上的描述:dinic算法就是不断用BFS构建层次图然后用DFS寻找增广.然后就是一下午的WA ,除了第一次调dinic的问题外,这道题竟然有多组数据!!!看discuss里好像还有重边的问题,可我用的邻接表有效避免了这个问题~~ #include <iostream> #include <cstdio> #include<str…

网络流模板题. ========================================================================================================== #include<cstdio> #include<cstring> #include<iostream> #include<algorithm> #include<cmath> #include<queue>…

题意:现在有m个池塘(从1到m开始编号,1为源点,m为汇点),及n条有向水渠,给出这n条水渠所连接的点和所能流过的最大流量,求从源点到汇点能流过的最大流量 Dinic #include<iostream> #include<cstring> #include<algorithm> #include <cstdio> #include <queue> using namespace std; ; const int INF = 0x3f3f3f3f…

#include<cstdio> #include<algorithm> #include<cstring> #include<queue> #define N 250 #define M 250 #define INF 100000000 using namespace std; int head[N],cur[N],lev[N],ecnt=1,S,T,n,m; queue <int> q; struct adj { int nxt,v,w;…

#include<cstdio> #include<cstring> #include<algorithm> using namespace std; int n, m, S, T; ;//点数的最大值 ;//边数的最大值 const int INF = 0x3f3f3f3f; struct Edge { int to,next,cap,flow; } edge[MAXM]; //注意是MAXM int tol; int head[MAXN]; void init()…

这道题用dinic会超时 用E_K就没问题 注意输入数据有重边.POJ1273 dinic的复杂度为O(N*N*M)E_K的复杂度为O(N*M*M)对于这道题,复杂度是相同的. 然而dinic主要依靠Dfs寻找增广路,故而使用了太多次递归,而利用bfs寻找增广路(使用队列而不用递归)的EK等于用栈的方式实现了dinic的递归,所以 大幅提高了效率. 最大流算法的核心就是找到增广路并且增加反向边流量,理解了这个,最大流算法就很简单了. #include<iostream> #include<…

题意:给出起点是一个池塘,M条沟渠,给出这M条沟渠的最大流量,再给出终点是一条河流,问从起点通过沟渠最多能够排多少水到河流里面去 看的紫书的最大流,还不是很理解,照着敲了一遍 #include<iostream> #include<cstdio> #include<cstring> #include <cmath> #include<stack> #include<vector> #include<map> #includ…

                                                         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…

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…

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 //…

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…

一直不明白为什么我的耗时几百毫秒,明明差不多的程序啊,我改来改去还是几百毫秒....一个小时后:明白了,原来把最大值0x3f(77)取0x3f3f3f3f就把时间缩短为16ms了.可是为什么原来那样没有WA呢?哦,明白了,因为最大值写小了,dicnic会多跑几遍.嗯顺便:0x3f3f3f3f也就是1061109567,也就是10^9级别的,是一个很大的数,而且加上一个10^9级别以下的数字也不会溢出.所以很多时候最大值取这个会比较好.最大的int是0x7fffffff,可以用常量INT_MAX…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=1532 思路分析:问题为最大网络流问题,给定一个有向图,需要求解该有向图的最大网络流,使用EdmondsKarp算法求解: 需要注意输入的边中可能有重边的存在: 代码如下: #include <queue> #include <vector> #include <cstdio> #include <climits> #include <cstring>…