萌新求助Dinic

我是参考的第一篇题解写的，但WA了#3#4#5，不知道该怎么改，请问错在哪？

请无视掉前面的namespace

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <queue>
#include <cstring>
#define MAXN 1000002
#define INF 2000000000
namespace STman {
    template <typename Tp>
    inline void read(Tp &x) {
    #define C getchar()
        Tp f = 1;
        x = 0;
        char k = C;
        while (k < '0' || k > '9') {
            if (k == '-') f = -1;
            k = C;
        }
        while (k >= '0' && k <= '9') {
            x = x * 10 + k - '0';
            k = C;
        }
        x = x * f;
    #undef C
    }
    template <typename Tp>
    inline void write(Tp x) {
        if (x < 0) putchar('-') , x = -x;
        if (x > 9) write(x / 10);
        putchar(x % 10 + '0');
    }
    template <typename Tp>
    inline Tp max(Tp a , Tp b) {
        if (a > b) return a;
        else return b;
    }
    template <typename Tp>
    inline Tp min(Tp a , Tp b) {
        if (a < b) return a;
        else return b;
    }
    template <typename Tp>
    inline void swap(Tp &a , Tp &b) {
        Tp t = a;
        a = b;
        b = a;
    }
    template <typename Tp>
    inline Tp abs(Tp &a) {
        if (a < 0) return -a;
        else return a;
    }
    inline void sp() {
        putchar(32);
    }
    inline void et() {
        putchar(10);
    }
}
using namespace STman;
struct Edge {
    int v , nx , w;
} e[MAXN];
std::queue <int> q;
int n , m , head[MAXN] , ecnt , x , y , z , r , k , dep[MAXN] , cur[MAXN];
void add(int f , int t , int w) {
    e[++ecnt] = (Edge) {t , head[f] , w};
    head[f] = ecnt;
    e[++ecnt] = (Edge) {f , head[t] , 0};
    head[t] = ecnt;
}
bool bfs(int s , int t) {
    memset(dep , 0x7f , sizeof(dep));
    while (!q.empty()) q.pop();
    for (int i = 1 ; i <= n ; i++) {
        cur[i] = head[i];
    }
    dep[s] = 0;
    q.push(s);
    while (!q.empty()) {
        int v = q.front();
        q.pop();
        for (int i = head[v] ; i ; i = e[i].nx) {
            int to = e[i].v;
            if (dep[to] > INF && e[i].w) {
                dep[to] = dep[v] + 1;
                q.push(to);
            }
        }
    }
    if (dep[t] < INF) return 1;
    else return 0;
}
int dfs(int u , int t , int l) {
    if (!l || u == t) return l;
    int fl = 0 , f;
    for (int i = cur[u] ; i ; i = e[i].nx) {
        cur[u] = i;
        int to = e[i].v;
        if (dep[to] == dep[u] + 1 && (f = dfs(to , t , min(l , e[i].w)))) {
            fl += f;
            l -= f;
            e[i ^ 1].w += f;
            e[i].w -= f;
            if (!l) break;
        }
    }
    return fl;
}
int Dinic(int s , int t) {
    int maxf = 0;
    while (bfs(s , t)) {
        maxf += dfs(s , t , INF);
    }
    return maxf;
}
int main() {
    read(n) , read(m) , read(r) , read(k);
    for (int i = 1 ; i <= m ; i++) {
        read(x) , read(y) , read(z);
        add(x , y , z);
    }
    write(Dinic(r , k));
    return 0;
}