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;