rt,TLE on # 9, #10

#include<bits/stdc++.h>
#define int long long
using namespace std;
int n,m,s,t;
const int maxn = 5000;
int head[maxn<<1],nex[maxn<<1],to[maxn<<1],cap[maxn<<1],flow[maxn<<1],cnt = 1;
const int INF = 1e18;
void add(int u,int v,int w1,int w2){
	nex[++cnt] = head[u];
	head[u] = cnt;
	to[cnt] = v;
	cap[cnt] = w1;
	flow[cnt] = w2;
} 
queue<int> q;
int ans;
int h[maxn],num[maxn],pre[maxn];
void make_high(){
	memset(h,-1,sizeof(h));
	h[t] = 0;
	num[0]++;//±ðÍüÁË£¡ 
	q.push(t);
	while(!q.empty()){
		int r = q.front();
		q.pop();
		for(int i = head[r];i;i = nex[i]){
			//cout << h[3] << " ";
			if(cap[i] == 0&&h[to[i]] == -1){
				h[to[i]] = h[r]+1;
				num[h[to[i]]]++;
				q.push(to[i]);
			}
		}
	}
}
void ISAP(){
	if(h[s] >= n){
		return;
	}
	int x = s;
	int d = INF;
	bool b = false;
	while(h[s] < n){
		x = s;
		d = INF;
		/*for(int i = 1;i <= n;i++){
			cout << h[i] << " ";
		}*/
		//cout << endl;
		while(x != t){
			b = false;
			for(int i = head[x];i;i = nex[i]){
				if(cap[i] > flow[i]&&h[x] > h[to[i]]){
					d = min(d,cap[i]-flow[i]);
					pre[to[i]] = i;
					x = to[i];
					b = true;
					break;
				}
			}
			if(b == false){
				int hm = INF;
				for(int i = head[x];i;i = nex[i]){
					if(cap[i] > flow[i]){
						hm = min(hm,h[to[i]]);//×¢ÒâÕâÀïÊÇ×îСֵ 
					}
				}
				if(num[h[x]] == 1){
					return;
				}
				num[h[x]]--;
				if(hm == INF){
					h[x] = n;
				}
				else{
					h[x] = hm+1;	
				}
				//h[x]++;
				num[h[x]]++;
				break;
			}
		}
		if(x == t){
			ans += d;
			for(int i = pre[t];i;i = pre[to[i^1]]){
				flow[i] += d;
				flow[i^1] -= d;
			}
		}
	}
}
signed main()
{
 	//freopen(".in","r",stdin);
	//freopen(".out","w",stdout);
	cin >> n >> m >> s >> t;
	int u,v,w;
	for(int i= 1;i <= m;i++){
		scanf("%lld%lld%lld",&u,&v,&w);
		add(u,v,w,0);
		add(v,u,0,0);
	}
	make_high();
	ISAP();
	cout << ans << endl;
	return 0;
}
/*
Author: qige_mingzi
Start thinking at
Start coding at
Finish coding at
Finish debugging at
*/