【模板】最小费用最大流

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <queue>
#include <cstdlib>

using namespace std;
const int N = 1e4 + 10;//dian
const int NN = 1e5 + 10;//bian
const int INF = 9999999; 

int head[N], dis[N], belong[N];
bool vis[N];
int n, m, S, T, now = 1;
int now_flow, ans_flow, ans_mon;
struct Node{
    int u, v, flow, money, nxt;
}E[NN];
queue <int> Q; 

inline int read()
{
    int x = 0, f = 1;
    char c = getchar();
    while(c < ‘0‘ || c > ‘9‘)
    {
        if(c == ‘-‘)
            f = -1;
        c = getchar();
    }
    while(c >= ‘0‘ && c <= ‘9‘)
    {
        x = x * 10 + c - ‘0‘; 
        c = getchar();
    }
    return x * f;
}

inline void add(int u,int v,int cap,int money)
{
    E[now].u = u;
    E[now].v = v;
    E[now].flow = cap;
    E[now].money = money;
    E[now].nxt = head[u];
    head[u] = now++;
}

int dfs(int start,int minn)
{
    if(start == S)
        return minn;
    int bel = belong[start];
    int ret = dfs(E[bel].u, min(minn, E[bel].flow));
    if(!E[bel ^ 1].money)
    {
        now = bel ^ 1;
        add(start, E[bel].u, 0, -E[bel].money);
    }
    E[bel].flow -= ret;
    E[bel ^ 1].flow += ret;
    return ret;
}
inline void MCMF()
{
    while(1)
    {
        for(int i = 1; i <= n; i ++)
            dis[i] = INF, vis[i] = 0;
        dis[S] = 0;
        Q.push(S);
        while(!Q.empty())
        {
            int topp = Q.front();
            Q.pop();
            vis[topp] = 0;
            for(int i = head[topp]; ~ i; i = E[i].nxt)
            {
                if(dis[E[i].v] > dis[topp] + E[i].money && E[i].flow)
                {
                    dis[E[i].v] = dis[topp] + E[i].money;
                    belong[E[i].v] = i;
                    if(!vis[E[i].v])
                    {
                        vis[E[i].v] = 1;
                        Q.push(E[i].v);
                    }
                }
            }
        }
        if(dis[T] == INF)
        {
            printf("%d %d",ans_flow,ans_mon);
            exit(0);
        }
        now_flow = dfs(T, INF);
        ans_flow += now_flow;
        ans_mon += now_flow * dis[T];
    }
}

int main()
{
    n = read();
    m = read();
    S = read();
    T = read();
    for(int i = 1; i <= n; i ++)
        head[i] = -1;
    for(int i = 1; i <= m; i ++)
    {
        int u = read();
        int v = read();
        int cap =read();
        int money = read();
        now ++;
        add(u, v, cap, money); 
    }
    MCMF();
    return 0;
}