原题，-1输出不了

#include <bits/stdc++.h>
using namespace std;
int n,a,b,k[205],vis[205];
queue <int> q;
int main()
{
	cin >> n >> a >> b;
	if (a == b)
	{
		cout << 0;
		return 0; 	
	}
	for (int i = 1;i <= n;i++) cin >> k[i];
	q.push(a);
	vis[a] = 0;
	memset(vis,2e9,sizeof(vis));
	while (!q.empty())
	{
		int x = q.front();
		q.pop();
		if (x + k[x] <= n)
		{
			if (!vis[x + k[x]])
			{
				q.push(x + k[x]);
				vis[x + k[x]] = vis[x] + 1;
			}
		}
		if (x - k[x] > 0)
		{
			if (!vis[x - k[x]])
			{
				q.push(x - k[x]);
				vis[x - k[x]] = vis[x] + 1;
			}
		}
	}
	cout << (vis[b] == 2e9?-1:vis[b]);
	return 0;
}