只有40分，求大佬帮忙看看代码

#include<algorithm>
#include<cstdio>
#include<queue>
#include<memory.h>
using namespace std;
#define N 1000005
#define maxx 99999999
int edge_num;
int head[N];
int n,m,s,t;
struct EDGE
{
    int to;
    int next;
    int f=0;
    int c;
}edge[N];
int dep[N];
int bfs()
{   queue <int> q;
    memset(dep,0,sizeof(dep));
    dep[s]=1;
    q.push(s);
    while (!q.empty())
    {
        int x=q.front();q.pop();
        for (int i=head[x];i;i=edge[i].next)
        {
        int go=edge[i].to;
        if (!dep[go]&&edge[i].f<edge[i].c)
        {
            dep[go]=dep[x]+1;
            q.push(go);
            }    
        }
    }
    return dep[t];
}
int dfs(int x,int flow)
{
    if (x==t) return flow;
    int ans=0;
    for (int i=head[x];i;i=edge[i].next)
    {
        if (flow<=ans) break;
        int go=edge[i].to;
        if (dep[go]==dep[x]+1&&edge[i].c>edge[i].f)
        {
        int s=dfs(go,min(flow-ans,edge[i].c-edge[i].f));
        ans+=s;
        edge[i].f+=s;
        edge[i^1].f-=s;    
        }    
    }
    return ans;
}
int dinic()
{
    int ans=0;
    while (bfs())
    {
    ans+=dfs(s,maxx);
    }
    return ans;
}
int main()
{
    scanf("%d %d %d %d",&n,&m,&s,&t);
    for (int i=1;i<=m;i++)
    {
        int a,b,c;
        scanf("%d %d %d",&a,&b,&c);
        edge[++edge_num].next=head[a];edge[edge_num].c=c;edge[edge_num].to=b;head[a]=edge_num; 
        edge[++edge_num].next=head[b];edge[edge_num].c=0;edge[edge_num].to=a;head[b]=edge_num;
    }
    int ans=dinic();
    printf("%d",ans); 
    return 0;
}