hdu 1548 A strange lift

题目链接：

http://acm.hdu.edu.cn/showproblem.php?pid=1548

解题思路：

和hdu2717很相似，也是按题意来，直接搜就行了。。。

AC代码：

#include <iostream>
#include <cstdio>
#include <cstring>
#include <queue>
using namespace std;

const int N = 200;
int n,A,B;
int a[N+10];
int vis[N+10];

bool bfs(){
    queue<int> q;
    q.push(A);
    memset(vis,0,sizeof(vis));
    while(!q.empty()){
        int cur = q.front();
        q.pop();
        //cout<<cur<<endl;
        if(cur == B)
            return true;
        int next = cur-a[cur];
        if(next>=0 && !vis[next]){
            vis[next] = vis[cur]+1;
            q.push(next);
        }
        next = cur+a[cur];
        if(next<=n && !vis[next]){
            vis[next] = vis[cur]+1;
            q.push(next);
        }
    }
    return false;
}

int main(){
    while(scanf("%d",&n),n){
        scanf("%d%d\n",&A,&B);
        for(int i = 1; i <= n; i++)
            scanf("%d",&a[i]);
        if(bfs())
            printf("%d\n",vis[B]);
        else
            printf("-1\n");
    }
    return 0;
}