Codeforces 500A - New Year Transportation【DFS】

题意：给出n个数，终点t

从第i点能够跳到i+a[i],问能否到达终点

 #include<iostream>
 #include<cstdio>
 #include<cstring>
 #include <cmath>
 #include<stack>
 #include<vector>
 #include<map>
 #include<set>
 #include<queue>
 #include<algorithm>
 #define mod=1e9+7;
 using namespace std;

 typedef long long LL;
 const int INF = 0x7fffffff;
 const int maxn=;
 int a[maxn],vis[maxn];
 int n,t;
 int flag=;

 void dfs(int x){
     if(vis[x]) return;
     vis[x]=;
     int xx=x+a[x];
     if(xx==t){
         flag=;
         return;
     }
     dfs(xx);
 }

 int main(){
     scanf("%d %d",&n,&t);
     memset(vis,,sizeof(vis));
     for(int i=;i<n;i++) scanf("%d",&a[i]);
     dfs();
     if(flag) printf("YES\n");
     else printf("NO\n");
     return ;
 }