1 #include <stdio.h>
 2 #include <string.h>
 3 #include <queue>
 4 using namespace std;
 5 bool isw[100010];
 6 int step[100010];
 7 void bfs(int n,int k)
 8 {
 9     memset(isw,0,sizeof(isw));
10     queue <int> q;
11     int cur,next;
12     cur = n;
13     step[n] = 0;
14     isw[cur] = true;
15     q.push(cur);
16     while(!q.empty()){
17         cur = q.front();
18         q.pop();
19         if(cur==k)    //找到，返回结果
20             return ;
21         int i;
22         for(i=1;i<=3;i++){    //步行，或者传送
23             switch(i){
24                 case 1:
25                     next = cur - 1;
26                     if(isw[next])    //剪枝，走过的不能走
27                         break;
28                     if(next<0 || next>100010)    //剪枝，越界不能再走
29                         break;
30                     step[next] = step[cur] + 1;
31                     q.push(next);
32                     isw[next] = true;
33                     break;
34                 case 2:
35                     next = cur + 1;
36                     if(isw[next])
37                         break;
38                     if(next<0 || next>100010)
39                         break;
40                     step[next] = step[cur] + 1;
41                     q.push(next);
42                     isw[next] = true;
43                     break;
44                 case 3:
45                     next = cur * 2;
46                     if(isw[next])
47                         break;
48                     if(next<0 || next>100010)
49                         break;
50                     step[next] = step[cur] +1;
51                     q.push(next);
52                     isw[next] = true;
53                     break;
54             }
55         }
56     }
57 }
58 int main()
59 {
60     int n,k;
61     while(scanf("%d%d",&n,&k)!=EOF){
62         bfs(n,k);
63         printf("%d\n",step[k]);
64     }
65     return 0;
66 }