网络流最大流Dinic算法（模板）

最大流算法的Edmonds-Karp算法，Maxflow返回最大流的值

#include<bits/stdc++.h>
using namespace std;
const int inf=2e9;
const int maxn=1005;

struct Edge{
    int from,to,cap,flow;
    Edge(int u,int v,int c,int f):from(u),to(v),cap(c),flow(f){}
};

struct Dinic{
    int n,m,s,t;
    vector<Edge> edges;
    vector<int> g[maxn];
    bool vis[maxn];
    int d[maxn];
    int cur[maxn];

    void init(int n){
        this->n=n;
        for(int i=0;i<=n;i++) g[i].clear();
        edges.clear();
    }

    void add(int from,int to,int cap){
        edges.push_back(Edge(from,to,cap,0));
        edges.push_back(Edge(to,from,0,0));
        m=edges.size();
        g[from].push_back(m-2);
        g[to].push_back(m-1);
    }

    bool BFS(){
        memset(vis,0,sizeof(vis));
        queue<int> que;
        que.push(s);
        d[s]=0;
        vis[s]=1;
        while(!que.empty()){
            int x=que.front();que.pop();
            for(int i=0;i<g[x].size();++i){
                Edge& e=edges[g[x][i]];
                if(!vis[e.to] && e.cap>e.flow){
                    vis[e.to]=1;
                    d[e.to]=d[x]+1;
                    que.push(e.to);
                }
            }
        }
        return vis[t];
    }

    int DFS(int x,int a){
        if(x==t || a==0) return a;
        int flow=0,f;
        for(int& i=cur[x];i<g[x].size();++i){
            Edge& e=edges[g[x][i]];
            if(d[x]+1==d[e.to] && (f=DFS(e.to,min(a,e.cap-e.flow)))>0){
                e.flow+=f;
                edges[g[x][i]^1].flow-=f;
                flow+=f;
                a-=f;
                if(a==0) break;
            }
        }
        return flow;
    }

    int Maxflow(int s,int t){
        this->s=s;this->t=t;
        int flow=0;
        while(BFS()){
            memset(cur,0,sizeof(cur));
            flow+=DFS(s,inf);
        }
        return flow;
    }
};