蒟蒻汗流浃背.......

样例通过但是全WA

#include <iostream>
#include <vector>
#include <cstring>
#include <queue>
using namespace std;
vector<int>t[1000010];
int n, m;
bool vs[1000010];
void dfs(int x)
{
	cout << x << ' ';
	for (int i = 0;i < t[x].size();i++)
	{
		if(!vs[t[x][i]])
		{
			vs[t[x][i]] = 1;
			dfs(t[x][i]);
		}
	}
}
int main(void)
{
	cin >> n >> m;
	for (int i = 0;i < m;i++)
	{
		int x, y;
		cin >> x >> y;
		t[x].push_back(y);
	}
	memset(vs, 0, sizeof(vs));
	vs[1] = 1;
	dfs(1);
	cout << endl;
	memset(vs, 0, sizeof(vs));
	queue<int>a;
	vs[1] = 1;
	a.push(1);
	while (!a.empty())
	{
		int k = a.front();
		a.pop();
		cout << k << ' ';
		for (int i = 0;i < t[k].size();i++)
		{
			if (!vs[t[k][i]])
			{
				vs[t[k][i]] = 1;
				a.push(t[k][i]);
			}
		}
	}
}