hdu1532(最大流模板)

http://acm.hdu.edu.cn/showproblem.php?pid=1532

 

#include<bits/stdc++.h>
#define inf 0x3f3f3f3f
using namespace std;
const int Ni = 210;
struct Edge{
    int u,v,c;
    int next;
}edge[20*Ni];
int n,m;
int edn;//=cnt边数
int p[Ni];//父亲
int d[Ni];//分层 
int sp,tp;//原点，汇点
void add(int u,int v,int c)
{
    edge[edn].u=u; edge[edn].v=v; edge[edn].c=c;
    edge[edn].next=p[u]; p[u]=edn++;
    
    edge[edn].u=v; edge[edn].v=u; edge[edn].c=0;
    edge[edn].next=p[v]; p[v]=edn++;
}
int bfs()
{
    queue <int> q;
    memset(d,-1,sizeof(d));
    d[sp]=0;
    q.push(sp);
    while(!q.empty())
    {
     int cur=q.front();
     q.pop();
     for(int i=p[cur];i!=-1;i=edge[i].next)
     {
         int u=edge[i].v;
         if(d[u]==-1 && edge[i].c>0)
         {
             d[u]=d[cur]+1;
             q.push(u);
         }
     }
    }
    return d[tp] != -1;
}
int dfs(int a,int b)
{
    int r=0;
    if(a==tp)return b;
    for(int i=p[a];i!=-1 && r<b;i=edge[i].next){
        int u=edge[i].v;
        if(edge[i].c>0 && d[u]==d[a]+1){
            int x=min(edge[i].c,b-r);
            x=dfs(u,x);
            r+=x;
            edge[i].c-=x;
            edge[i^1].c+=x;
        }
    }
    if(!r)d[a]=-2;
    return r;
}

int dinic(int sp,int tp)
{
    int total=0,t;
    while(bfs())
    {
        while(t=dfs(sp,inf))
        total+=t;
    }
    return total;
}
int main(){
    int i,u,v,c;
    while(~scanf("%d%d",&m,&n))
    {
     edn=0;//初始化
     memset(p,-1,sizeof(p));
     sp=1;tp=n;
     for(i=0;i<m;i++)
     {
         scanf("%d%d%d",&u,&v,&c);
         add(u,v,c);
     }
     printf("%d\n",dinic(sp,tp));
    }
 return 0;
}