lingo求最小费用最大流问题的代码

以下是一个基于Dijkstra算法的最小费用最大流实现代码：

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

using namespace std;

const int INF = 0x7fffffff;
const int MAXN = 1005;
const int MAXM = 10005;

int n, m, s, t, ans_flow, ans_cost, head[MAXN], h[MAXN], pre[MAXN];
bool vis[MAXN];

struct Edge{
    int to, nxt, flow, cost;
}edge[MAXM << 1];

void addEdge(int from, int to, int flow, int cost){
    edge[m].to = to;
    edge[m].flow = flow;
    edge[m].cost = cost;
    edge[m].nxt = head[from];
    head[from] = m++;
    edge[m].to = from;
    edge[m].flow = 0;
    edge[m].cost = -cost;
    edge[m].nxt = head[to];
    head[to] = m++;
}

bool spfa(){
    queue<int> q;
    memset(h, 0x3f, sizeof(h));
    memset(vis, false, sizeof(vis));
    memset(pre, -1, sizeof(pre));
    h[s] = 0;
    q.push(s);
    while(!q.empty()){
        int u = q.front();
        q.pop();
        vis[u] = false;
        for(int i = head[u]; ~i; i = edge[i].nxt){
            int v = edge[i].to;
            if(edge[i].flow && h[v] > h[u] + edge[i].cost){
                h[v] = h[u] + edge[i].cost;
                pre[v] = i;
                if(!vis[v]){
                    vis[v] = true;
                    q.push(v);
                }
            }
        }
    }
    return pre[t] != -1;
}

void MCMF(){
    while(spfa()){
        int min_flow = INF;
        for(int i = pre[t]; ~i; i = pre[edge[i ^ 1].to]){
            min_flow = min(min_flow, edge[i].flow);
        }
        ans_flow += min_flow;
        ans_cost += min_flow * h[t];
        for(int i = pre[t]; ~i; i = pre[edge[i ^ 1].to]){
            edge[i].flow -= min_flow;
            edge[i ^ 1].flow += min_flow;
        }
    }
}

int main(){
    memset(head, -1, sizeof(head));
    scanf("%d%d%d%d", &n, &m, &s, &t);
    for(int i = 1; i <= m; i++){
        int u, v, f, c;
        scanf("%d%d%d%d", &u, &v, &f, &c);
        addEdge(u, v, f, c);
    }
    MCMF();
    printf("%d %d\n", ans_flow, ans_cost);
    return 0;
}

该代码实现了最小费用最大流，其中s和t分别代表源点和汇点。通过添加addEdge函数，将边加入邻接表中，然后通过MCMF函数调用Dijkstra算法求解最小费用最大流。最后输出最大流和最小费用即可。