A. New Year Transportation 1000 / 水题

Posted 2021-10-02 幽殇默

https://codeforces.com/problemset/problem/500/A

#include<bits/stdc++.h>
using namespace std;
int main(void)
{
	int n,m; cin>>n>>m;
	int startx=1;
	bool flag=0;
	for(int i=1;i<=n-1;i++)
	{
		int a; cin>>a;
		if(startx==i) startx+=a;
		if(startx==m) flag=1;
	}
	if(flag) puts("YES");
	else puts("NO");
	return 0;
}