网络流Dinic算法模板 POJ1273

这就是以后我的板子啦~~~

#include <queue>
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
#define N 444
int tot,next[N],first[N],w[N],v[N],n,m,ch[N];
void add(int from,int to,int weight){
    v[tot]=to;w[tot]=weight;
    next[tot]=first[from];
    first[from]=tot++;
}
bool tell(){
    memset(ch,-1,sizeof(ch));
    queue<int>q;
    q.push(1);ch[1]=0;
    while(!q.empty()){
        int t=q.front();q.pop();
        for(int i=first[t];~i;i=next[i])
            if(w[i]&&ch[v[i]]==-1)
                q.push(v[i]),ch[v[i]]=ch[t]+1;
    }
    return ch[n]!=-1;
}
int zeng(int a,int b){
    if(a==n)return b;
    int r=0;
    for(int i=first[a];~i&&b>r;i=next[i])
        if(ch[a]+1==ch[v[i]]&&w[i]){
            int t=zeng(v[i],min(b-r,w[i]));
            w[i]-=t;w[i^1]+=t;r+=t;
        }
    if(!r)ch[a]=-1;
    return r;
}
int dinic(){
    int ans=0,jy;
    while(tell())while(jy=zeng(1,0x3fffffff))ans+=jy;
    return ans;
}
int main(){
    while(scanf("%d%d",&m,&n)!=EOF){
        memset(first,-1,sizeof(first));
        register int xx,yy,zz;
        tot=0;
        for(int i=1;i<=m;i++){
            scanf("%d%d%d",&xx,&yy,&zz);
            add(xx,yy,zz);add(yy,xx,0);
        }
        printf("%d\n",dinic());
    }
}

还有一中写在结构体里面的：

（假设1为源点，n为汇点）

struct Dinic{
    int fst[N],next[N],w[N],v[N],vis[N],cnt;
    void init(){memset(fst,-1,sizeof(fst)),cnt=0;}
    void add(int x,int y,int z){
        w[cnt]=z,v[cnt]=y;
        next[cnt]=fst[x],fst[x]=cnt++;
    }
    bool tell(){
        memset(vis,-1,sizeof(vis));
        queue<int>q;
        q.push(1),vis[1]=0;
        while(!q.empty()){
            int t=q.front();q.pop();
            for(int i=fst[t];~i;i=next[i])
                if(w[i]&&vis[v[i]]==-1)
                    q.push(v[i]),vis[v[i]]=vis[t]+1;
        }
        return vis[n]!=-1;
    }
    int zeng(int x,int y){
        if(x==n)return y;
        int r=0;
        for(int i=fst[x];~i&&y>r;i=next[i]){
            if(w[i]&&vis[v[i]]==vis[x]+1){
                int t=zeng(v[i],min(y-r,w[i]));
                w[i]-=t,w[i^1]+=t,r+=t;
            }
        }
        if(!r)vis[x]=-1;
        return r;
    }
    void flow(){
        int ans=0,xx;
        while(tell())while(xx=zeng(1,0x3fffffff))ans+=xx;
        printf("%d\n",ans);
    }
}dinic;