http://acm.hdu.edu.cn/showproblem.php?pid=1548
之前用dfs写，，以为可以选择最小的，，当写到那时，就囧了，，不知道怎么处理。。或许真的可以用dfs只是可能要全部搜索才能判断。求路过的大牛指点一二dfs写法！
bfs写法：
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1 #include<stdio.h> 2 #include<string.h> 3 int map[205]; 4 int vis[205]; 5 int queue[205]; 6 int rear,front; 7 int count; 8 int n; 9 int bfs(int x,int y) 10 { 11 int top; 12 rear=0; 13 front=0; 14 15 queue[rear++]=x; 16 vis[x]=1; 17 //if(x==y) return count; 18 while(rear>front) 19 { 20 21 top=queue[front++]; 22 if(top-map[top]>=1&&vis[top-map[top]]==0) 23 { 24 queue[rear++]=top-map[top]; 25 vis[top-map[top]]=vis[top]+1; 26 27 } 28 if(top+map[top]<=n&&vis[top+map[top]]==0) 29 { 30 queue[rear++]=top+map[top]; 31 vis[top+map[top]]=vis[top]+1; 32 } 33 if(top==y) return vis[top]-vis[x]; 34 } 35 return -1; 36 } 37 int main() 38 { 39 int a,b; 40 int i; 41 while(~scanf("%d",&n),n) 42 { 43 scanf("%d%d",&a,&b); 44 //count=0; 45 memset(vis,0,sizeof(vis)); 46 for(i=1;i<=n;i++) 47 scanf("%d",&map[i]); 48 printf("%d\n",bfs(a,b)); 49 } 50 }