跑得很慢

#include <bits/stdc++.h>
using namespace std;
#define N 5005
#define M 100005
#define inf 0x3f3f3f3f
typedef pair<int, int> pii;
int S, T;
struct MCMF
{
    int hd[N], nxt[M], to[M], c[M], w[M], tot = 1, Cost, Flow;
    void add(int u, int v, int C, int W)
    {
        nxt[++tot] = hd[u], to[tot] = v, c[tot] = C, w[tot] = W, hd[u] = tot;
        nxt[++tot] = hd[v], to[tot] = u, c[tot] = 0, w[tot] = -W, hd[v] = tot;
    }
    void clear() { memset(hd, 0, sizeof(hd)), tot = 1; }
    int dis[N], cur[N];
    queue<int> q;
    bitset<N> in, vis;
    bool SPFA()
    {
        vis.reset();
        memset(dis, 0x3f, sizeof(dis));
        memcpy(cur, hd, sizeof(cur));
        q.push(S);
        dis[S] = 0, in[S] = 1;
        while (!q.empty())
        {
            int u = q.front();
            q.pop(), in[u] = 0;
            for (int i = hd[u]; i; i = nxt[i])
            {
                int v = to[i];
                if (!c[i]) continue;
                if (dis[v] > dis[u] + w[i])
                {
                    dis[v] = dis[u] + w[i];
                    if (!in[v])
                    {
                        q.push(v);
                        in[v] = 1;
                    }
                }
            }
        }
        return dis[T] != inf;
    }
    int DFS(int u, int now)
    {
        vis[u] = 1;
        if (u == T) return now;
        int res = 0;
        for (int i = cur[u]; i && now; i = nxt[i])
        {
            int v = to[i], C = c[i];
            cur[u] = i;
            if (dis[v] != dis[u] + w[i] || !C || vis[v]) continue;
            int flow = DFS(v, min(C, now));
            Cost += flow * w[i];
            c[i] -= flow, c[i ^ 1] += flow;
            now -= flow, res += flow;
        }
        return res;
    }
    void SSP()
    {
        int x;
        while (SPFA())
            while ((x = DFS(S, inf))) Flow += x;
    }
} G;
int n, m;
int main()
{
    cin >> n >> m >> S >> T;
    while (m--)
    {
        int u, v, c, w;
        cin >> u >> v >> c >> w;
        G.add(u, v, c, w);
    }
    G.SSP();
    cout << G.Flow << ' ' << G.Cost;
    return 0;
}