HDU 2717 Catch That Cow（BFS）

题目链接

好裸，BFS。杭电多组。。2A。。

 1 #include <stdio.h>

 2 #include <string.h>

 3 int p[100001],o[100001];

 4 int main()

 5 {

 6     int n,k,i,j,start=0,end=0,num=0;

 7     while(scanf("%d%d",&n,&k)!=EOF)

 8     {

 9         memset(o,0,sizeof(o));

10         start=0,end=0,num=0;

11         p[start] = n;

12         o[n] = 1;

13         for(;;)

14         {

15             if(o[k]) break ;

16             num ++;

17             j = 1;

18             for(i = start; i <= end; i ++)

19             {

20                 if(p[i]+1 <= 100000)

21                 {

22                     if(o[p[i]+1] == 0)

23                     {

24                         p[end+j] = p[i]+1;

25                         o[p[i]+1] = 1;

26                         j ++;

27                     }

28                 }

29                 if(p[i]-1 >= 0)

30                 {

31                     if(o[p[i]-1] == 0)

32                     {

33                         p[end+j] = p[i]-1;

34                         o[p[i]-1] = 1;

35                         j ++;

36                     }

37                 }

38                 if(p[i]*2 <= 100000)

39                 {

40                     if(o[p[i]*2] == 0)

41                     {

42                         p[end+j] = p[i]*2;

43                         o[p[i]*2] = 1;

44                         j ++;

45                     }

46                 }

47             }

48             start = end + 1;

49             end = end + j - 1;

50         }

51         printf("%d\n",num);

52     }

53     return 0;

54 }