toj2825 catch the cow BFS典型题

//toj2825 catch the cow BFS typical
#include<iostream>
#define MAX 999999
using namespace std;
int n,k;
int x[MAX],step[MAX],flag[MAX]={0};
int bfs(int a,int b)
{
int top,tx,i;
top=1;
step[0]=0;
x[0]=n;
for(i=0;i<top;i++)
{
if(x[i]==k)return step[i];
tx=x[i]-1;
if(tx<=100000&&tx>=0&&flag[tx]==0)
{
x[top]=tx;
step[top]=step[i]+1;
flag[tx]=1;
top++;
}
tx=x[i]+1;
if(tx<=100000&&tx>=0&&flag[tx]==0)
{
x[top]=tx;
step[top]=step[i]+1;
flag[tx]=1;
top++;
}
tx=x[i]*2;
if(tx<=100000&&tx>=0&&flag[tx]==0)
{
x[top]=tx;
step[top]=step[i]+1;
flag[tx]=1;
top++;
}
}
}
int main()
{
cin>>n>>k;
cout<<bfs(n,k)<<endl;
return 0;
}