HDOJ 2717

http://acm.hdu.edu.cn/showproblem.php?pid=2717

据说是水题，行吧，水了一个多点。

#include<stdio.h>


int p[100001];
int vis[100001];
int bfs(int farmer,int cow)
{
int right=1,left=0;
int tryy;
p[left]=farmer;
vis[farmer]=0;
while(left!=right)
{
farmer=p[left];
left++;
if(farmer==cow)
return vis[farmer];
tryy=farmer+1;
if(vis[tryy]==-1)
{
p[right++]=tryy;
vis[tryy]=vis[farmer]+1;
}
tryy=farmer-1;
if(vis[tryy]==-1 && tryy>=0)
{
p[right++]=tryy;
vis[tryy]=vis[farmer]+1;
}
tryy=farmer*2;
if(vis[tryy]==-1 && tryy<=100001)
{
p[right++]=tryy;
vis[tryy]=vis[farmer]+1;
}

}
return -1;
}
int main ()
{
int farmer,cow,i; 

while(scanf("%d %d",&farmer,&cow)!=EOF){

for(i=0;i<=100001;i++)
vis[i]=-1;
printf("%d\n",bfs(farmer,cow));
}
return 0;

}