/*Author:luogu uid 357163 shyr*/
#include<bits/stdc++.h>
#define For(i,a,b,c) for(int i=(a);i<=(b);i+=(c))
#define Rof(i,a,b,c) for(int i=(b);i>=(a);i-=(c))
using namespace std;
typedef long long LL;
typedef double db;
#define int long long 
typedef unsigned long long ULL;
template<typename t> t &read(t &x){
	char c;int f=1;
	while(!isdigit(c=getchar()))f=(c=='-')?-1:1;
	x=c^'0';
	while(isdigit(c=getchar()))x=x*10+(c^'0');
	return x*=f;
}
int n,Nxt[205],m,s,t,u,v,w,cnt=1,nxt[205],dep[205];
LL ans;
struct node{
	int a,b,c,lst;
	void add(int A,int B,int C){
		a=A,b=B,c=C,lst=nxt[a],nxt[a]=cnt;
	}
}g[10001];
bool BFS(){
	memset(dep,0,sizeof(dep));
	dep[s]=1;queue<int>q;q.push(s);
	while(q.size()){
		int x=q.front();q.pop();Nxt[x]=nxt[x];
		for(int i=nxt[x];i;i=g[i].lst){
			int y=g[i].b;
			if(g[i].c&&!dep[y]){
				dep[y]=dep[x]+1;
				q.push(y);
			}
		}
	}
	return dep[t];
}
LL DFS(int x,LL in){
	if(x==t)return in;
	LL out=0;
	for(int i=Nxt[x];i&&in;i=g[i].lst){
		Nxt[x]=i;int y=g[i].b;LL val=g[i].c;
		if(val&&dep[y]==dep[x]+1){
			LL res=DFS(y,min(in,val));
			g[i].c-=res,g[i^1].c+=res;
			in-=res,out+=res;
		}
	}
	if(!out)dep[x]=-1;
	return out;
}
#define LOCAL
signed main(){
	#ifdef LOCAL
		freopen("P3376_8.in","r",stdin);
		freopen("out.txt","w",stdout);
	#endif
	read(n),read(m),read(s),read(t);
	For(i,1,m,1){
		read(u),read(v),read(w);
		g[++cnt].add(u,v,w);
		g[++cnt].add(v,u,0);
	}
	while(BFS())ans+=DFS(s,1e18);
	printf("%lld\n",ans);
	return 0;
}

下了数据#8本地跑的答案是 37381805875，和 out 一样。

但是显示 wrong answer On line 1 column 9, read 9, expected 8.

求问。