Drainage Ditches

点击打开链接

意甲冠军：有因雨池塘，通过修通渠道流失。如何污水排放达？

解决：古典最大流量，通过改变容量，为了减少使用流量，了空间优化

#include<iostream>
#include<cmath>
#include<cstring>
#include<cstdio>
#include<queue>using namespace std;const  int maxn = 1005;
#define INF 0xfffffff
int n, m, u, v, value, sum, start, end;
int pre[ maxn ], cap[ maxn ][ maxn ], flow[ maxn ][ maxn ], dis[ maxn ];int EK (){queue< int > Q;sum = 0;while( 1 ){Q.push( start );memset( dis, 0, sizeof( dis ) );dis[ start ] = INF;while( !Q.empty() ){int temp = Q.front();Q.pop();for( int i = 1; i <= m; ++i ){if( ! dis[ i ] && cap[ temp ][ i ] > 0 ){dis[ i ] = min( dis[ temp ], cap[ temp ][ i ]  );    pre[ i ] = temp;Q.push( i );}}}if( dis[ m ] == 0 )break;sum += dis[ m ];for( int i = end; i != start; i = pre[ i ] ){cap[ pre[ i ] ][ i ] -= dis[ m ];cap[ i ][ pre[ i ] ] += dis[ m ];}}printf( "%d\n", sum );
}int main(){while( scanf( "%d%d", &n, &m ) != EOF ){memset( cap, 0, sizeof( cap ) );memset( flow, 0, sizeof( flow ) );start = 1, end = m;for( int i = 0; i < n; ++i ){scanf( "%d%d%d", &u, &v, &value );cap[ u ][ v ] += value;}EK( );}
}/*
5 4
1 2 40
1 4 20
2 4 20
2 3 30
3 4 1050
*/

Drainage Ditches相关推荐

网络流--最大流--POJ 1273 Drainage Ditches
链接 Description Every time it rains on Farmer John's fields, a pond forms over Bessie's favorite clov ...
Drainage Ditches POJ1273
Time Limit: 1000MS Memory Limit: 10000K Total Submissions: 93263 Accepted: 36174 试题链接文章目录 Descripti ...
USACO Section 4.2 Drainage Ditches（最大流）
最大流问题.ISAP算法.注意可能会有重边,不过我用的数据结构支持重边.距离d我直接初始化为0,也可以用BFS逆向找一次. -------------------------------------- ...
[POJ 1273]Drainage Ditches
[问题描述] Every time it rains on Farmer John's fields, a pond forms over Bessie's favorite clover patch ...
poj1273 Drainage Ditches
蒟蒻的blog POJ 1273 Drainage Ditches Time Limit: 1000MS Memory Limit: 10000K Memory Limit: 10000K Total ...
网络流 - Drainage Ditches - HDU - 1532
Problem Description Every time it rains on Farmer John's fields, a pond forms over Bessie's favorite ...
usaco Drainage Ditches(网络流dinic模板）
模板题 /* ID:jinbo wu TASK:ditch LANG:C++ */#include<bits/stdc++.h> using namespace std; #define ...
POJ 1273 Drainage Ditches
网络流. 题意非常easy.给出单向边,容量. 找最大流.注意重边要加起来.g[u][v].c+=c; 第一次写网络流. 也是第一个网络流的题. 看了两天,理解了之后就唰唰唰的写出来了. 大概可能是E ...
【网络流】解题报告：luogu P2740 [USACO4.2]草地排水Drainage Ditches（Edmonds-Karp增广路，最大流模板）
题目链接:草地排水若一条从源点到汇点的路径上各条边的剩余容量都大于0,则称这条路径为一条增广路. Edmonds-Karp增广路的策略就是不断用bfs寻找增广路,直至网络中不在存在增广路为止. 在每 ...

Drainage Ditches

Drainage Ditches相关推荐

最新文章

热门文章