不知道为什么50分

#include<bits/stdc++.h>
using namespace std;
int l,A,B;
queue<int> flr;
int step=0;
int stage[210]={0};
int mom[210]={0};
void dfs(){
	int x=flr.front();
	if(x==B){mom[B]=step;return ;}
	if(x<1 or x>l){flr.pop();return;}
	if(mom[x]!=0){flr.pop();return;}
	mom[x]=step;
	step++;
	flr.push(x+stage[x]);
	flr.push(x-stage[x]);
	flr.pop();
	return;
}
int main(){
cin>>l>>A>>B;
int i;
for(i=1;i<=l;i++){cin>>stage[i];}
flr.push(A);
mom[B]=-1;
while(mom[B]==-1 and flr.empty()==false){
		dfs();
	}
	cout<<mom[B];	
}