hdu3549最大流

来源：互联网发布：叶修官方手办淘宝编辑：程序博客网时间：2024/06/13 16:20

这应该是最裸的最大流题了吧，刚开始学最大流，拿来练练手。从源点到汇点的最大流，EK算法实现如下，不再多说：http://acm.hdu.edu.cn/showproblem.php?pid=3549

#include<iostream>#include<cstring>#include<cmath>#include<cstdio>using namespace std;#define INS 0xfffffff#define MAX 105int map[MAX][MAX],f[MAX];int r[MAX];bool vis[MAX];int m,n;bool bfs(){    int start,end,size,begin = 0;    start = end = 0; size = 100;    memset(vis,false,sizeof(vis));    r[start] = 1; int k = 1;    while(start <= end){         vis[ r[start] ] = true;        for(int i = 1;i <= n;++i){            if(!vis[i] && map[ r[start] ][i] > 0){                end = (end+1)%size;                f[i] = r[start]; r[end] = i;                 if(i == n) return true;            }        }        start = (start+1)%size;    }    return false;}int E_K(){    int d = INS,i,res = 0;    memset(f,-1,sizeof(f));    f[1] = 0;    while(bfs()){         i = n; d = INS;        while(f[i] != 0){            d = min(d,map[ f[i] ][i]);  i = f[i];         }        i = n; res += d;        while(f[i] != 0){            map[ f[i] ][i] -=d;            map[i][ f[i] ] +=d;              i = f[i];         }        memset(f,-1,sizeof(f)); f[1] = 0;    } return res;}int main(){    int t;    scanf("%d",&t);    for(int k = 1;k <= t;++k){        scanf("%d%d",&n,&m);        int b,e,v;        memset(map,0,sizeof(map));        for(int i = 0;i < m;++i){            scanf("%d%d%d",&b,&e,&v);            map[b][e] += v;        }        printf("Case %d: %d\n",k,E_K());    }    return 0;｝