CDZSC_2015寒假新人（4）——搜索 C

 1 #include <iostream>
 2 #include <cstring>
 3 #include <cstdio>
 4 #include <queue>
 5 using namespace std;
 6 int vis[210],le[210],n;
 7 int bfs(int a,int b)
 8 {
 9     int c;
10     memset(vis,0,sizeof(vis));
11     queue<int>q;
12     q.push(a);
13     while(!q.empty())
14     {
15         c=q.front();
16         q.pop();
17         if(c+le[c]<=n&&!vis[c+le[c]])
18         {
19             vis[c+le[c]]=vis[c]+1;
20             q.push(c+le[c]);
21         }
22         if(c-le[c]>=1&&!vis[c-le[c]])
23         {
24             vis[c-le[c]]=vis[c]+1;
25             q.push(c-le[c]);
26         }
27     }
28     if(vis[b]!=0)
29     {
30         return vis[b];
31     }
32     else
33     {
34         return -1;
35     }
36 }
37 int main()
38 {
39 #ifdef CDZSC_OFFLINE
40     freopen("in.txt","r",stdin);
41 #endif
42     int i,a,b,sum;
43     while(scanf("%d",&n)&&n!=0)
44     {
45         scanf("%d%d",&a,&b);
46         for(i=1; i<=n; i++)
47         {
48             scanf("%d",&le[i]);
49         }
50         if(a==b)//相同时输出0
51         {
52             printf("0\n");
53             continue;
54         }
55         sum=bfs(a,b);
56         printf("%d\n",sum);
57     }
58     return 0;
59 }