64分求调

#include<iostream>
using namespace std;
int n,a,b,k[201],ans=99999,p[201];
void dfs(int x,int y){
	if(x>n||x<=0)return ;
	if(x==b){
		ans=min(ans,y);
		return ;
	}
	if(p[x]!=0&&y>p[x])return;
	p[x]=y;
	dfs(x+k[x],y+1);dfs(x-k[x],y+1);
}
int main()
{
	cin>>n>>a>>b;
	for(int i=1;i<=n;++i)
	{
		cin>>k[i];
	}
	dfs(a,0);
	if(ans!=99999)
		cout<<ans<<endl;
	else 
		cout<<-1<<endl;
	return 0;
}