裸的广搜竟然能拿70分？

#include <iostream>
#include <queue>
#include <algorithm>
#include <cstdio>
#include <cstring>
using namespace std;
#define maxn 200005
int n, tmp, ans = 1e9, t[maxn], vis[maxn];
int bfs(int x) {
	int step = 1;
	queue<int> Q;
	Q.push(t[x]);
	while(!Q.empty()) {
		if(step > ans)
			return ans;
		int cur = Q.front();
		Q.pop();
//		printf("now=%d,nxt=%d,step=%d\n", cur, t[cur], step);
		if(!vis[t[cur]]) {
			vis[t[cur]] = 1;
			Q.push(t[cur]);
		}
		if(t[cur] == x)
			break;
		step ++;
	}
	return step + 1;
}
int main() {
	cin >> n;
	for(int i = 1; i <= n; i ++) {
		cin >> tmp;
		t[i] = tmp;
	}
	for(int i = 1; i <= n; i ++) {
//		cout << endl;
		ans = min(ans, bfs(i));
		memset(vis, 0, sizeof(vis));
	}
	cout << ans;
	return 0;
}