poj 3278 catch that cow

bfs，RE多次之后学习大牛的代码，不要惊讶怎么限定在100000范围内！

更好的解法：http://www.cnblogs.com/longzhiri/articles/1555344.html

 1 # include <stdio.h>
 2 # include <string.h>
 3 # include <queue>
 4 
 5 using namespace std;
 6 
 7 int n, k, x;
 8 int d[100002];
 9 queue<int>Q;
10 
11 int main()
12 {    
13     while (~scanf("%d%d", &n, &k))
14     {        
15         memset(d, 0, sizeof(d));
16         while (!Q.empty()) Q.pop();
17         Q.push(n);
18         while (!Q.empty())
19         {            
20             x = Q.front();
21             Q.pop();
22             if (x == k) break;
23             if (x > 0  && 0==d[x-1]) {Q.push(x-1); d[x-1] = d[x]+1;}
24             if (x < 100001 && 0==d[x+1]) {Q.push(x+1); d[x+1] = d[x]+1;}
25             if ((x<<1) < 100001 && 0==d[x<<1]) {Q.push(x<<1); d[x<<1] = d[x]+1;}
26         }
27         printf("%d\n", d[k]);
28     }
29     
30     return 0;
31 }