EK 被卡90分 求助

RT.

#include<bits/stdc++.h>
#define reg register
#define ll long long
#define inf 0x3f3f3f3f
using namespace std;
struct edge
{
    int from,to,x,flow,pre;
}e[1000005];
queue<int>q;
int m,n,h[1000005],tot,pre[1000005],a[1000005],flow,s,t,x,y,z;
inline void clear(queue<int>&q) 
{
    queue<int>x;
    swap(x,q);
}
inline void addedge(int from,int to,int x)
{
    tot++;
    e[tot].from=from;
    e[tot].to=to;
    e[tot].x=x;
    e[tot].flow=0;
    e[tot].pre=h[from];
    h[from]=tot;
}
int main()
{
    scanf("%d%d%d%d",&m,&n,&s,&t);
    for(reg int i=1;i<=n;i++)
    {
        scanf("%d%d%d",&x,&y,&z);
        addedge(x,y,z);
        addedge(y,x,0);
    }
    while(1)
    {
        memset(a,0,sizeof(a));
        clear(q);
        q.push(s);
        a[s]=inf;
        pre[s]=0;
        while(!q.empty())
        {
            reg int u=q.front();
            q.pop();
            for(int i=h[u];i;i=e[i].pre)
            {
                reg int v=e[i].to;
                if(!a[v]&&e[i].x>e[i].flow)
                {
                    a[v]=min(a[u],e[i].x-e[i].flow);
                    pre[v]=i;
                    q.push(v);
                }
            }
            if(a[t])break;
        }
        if(!a[t])break;
        for(int u=t;u!=s;u=e[pre[u]].from)
        {
            e[pre[u]].flow+=a[t];
            e[(pre[u]-1)^1+1].flow-=a[t];
        }
        flow+=a[t];
    }
    printf("%d",flow);
    return 0;
}

附赠第3个点(被卡掉的点)数据: input:

10 25 2 10
3 4 4
4 3 45
3 5 80
1 6 94
3 7 63
9 8 92
1 9 75
6 3 12
7 9 63
6 1 39
6 1 97
9 7 33
7 4 55
8 9 36
5 2 61
9 8 97
2 4 36
1 2 2
10 2 14
5 9 82
5 1 32
6 2 94
9 2 10
6 10 50
7 6 53

output:

36