网络流--最大流ek模板

标准大白书式模板，代码简单但由于效率并不高，所以并不常用，就是这样

#include<stdio.h>
#include<string.h>
#include<queue>
#include<vector>
#include<algorithm>
using namespace std;
const int maxm=150+5;
const int INF=0x3f3f3f3f;

struct edge{
    int from,to,c,f;
    edge(int a,int b,int m,int n):from(a),to(b),c(m),f(n){}
};

struct ek{
    int n,m;
    vector<edge>e;
    vector<int>g[maxm];
    int a[maxm];
    int p[maxm];

    void init(int n){
        for(int i=0;i<n+3;i++)g[i].clear();
        e.clear();
    }

    void add(int from,int to,int c){
        e.push_back(edge(from,to,c,0));
        e.push_back(edge(to,from,0,0));
        m=e.size();
        g[from].push_back(m-2);
        g[to].push_back(m-1);
    }

    int mf(int s,int t){
        int f=0;
        while(1){
            memset(a,0,sizeof(a));
            queue<int>q;
            q.push(s);
            a[s]=INF;
            while(!q.empty()){
                int u=q.front();
                q.pop();
                for(int i=0;i<g[u].size();i++){
                    edge tmp=e[g[u][i]];
                    if(!a[tmp.to]&&tmp.c>tmp.f){
                        p[tmp.to]=g[u][i];
                        a[tmp.to]=min(a[u],tmp.c-tmp.f);
                        q.push(tmp.to);
                    }
                }
                if(a[t])break;
            }
            if(!a[t])break;
            for(int i=t;i!=s;i=e[p[i]].from){
                e[p[i]].f+=a[t];
                e[p[i]^1].f-=a[t];

            }
            f+=a[t];
        }
        return f;
    }
};