刷道水题，没想到被水题刷了……全WA

#include <bits/stdc++.h>
#define int long long

using namespace std;

int n, m;
int x, y;
vector <int> v[1005];
bool vis[20000];

void dfs (int x, int mx){
	
	if (v[x].size () == 0){
		
		cout << mx << ' ';
		return;
		
	}
	
	vis[x] = 1;
	
	for (int i = 0; i < v[x].size (); i ++){
		
		if (vis[v[x][i]] == 0)
			dfs (v[x][i], max (mx, v[x][i]));
		
	}
	
}

signed main(){
	
	cin >> n >> m;
	
	for (int i = 1; i <= m; i ++){
		
		cin >> x >> y;
		v[x].push_back (y); 
		
	}
	
	for (int i = 1; i <= n; i ++){
		
		memset (vis, 0, sizeof (vis));
		dfs (i, i);
		
	}
	
}