Farmer John has been informed of the location of a fugitive cow and wants to catch her immediately. He starts at a point N (0 ≤ N ≤ 100,000) on a number line and the cow is at a point K (0 ≤ K ≤ 100,000) on the same number line. Farmer John has two modes of transportation: walking and teleporting.
* Walking: FJ can move from any point X to the points X – 1 or X + 1 in a single minute
* Teleporting: FJ can move from any point X to the point 2 × X in a single minute.
If the cow, unaware of its pursuit, does not move at all, how long does it take for Farmer John to retrieve it?

Line 1: Two space-separated integers: N and K

Line 1: The least amount of time, in minutes, it takes for Farmer John to catch the fugitive cow.

5 17

4

#include <iostream>
#include <queue>
using namespace std;
int n,k;
bool book[200005];
queue<int> que,disque,cq;
int main()
{
while(cin>>n>>k)
{
for(int i=0;i<200005;i++)book[i]=0;
book[n]=1,que=disque=cq,que.push(n),disque.push(0);
while(!que.empty())
{
if(que.front()==k){cout<<disque.front()<<endl;break;}
if(que.front()>0)if(!book[que.front()-1])que.push(que.front()-1),disque.push(disque.front()+1),book[que.front()-1]=1;
if(que.front()<k&&!book[que.front()+1])que.push(que.front()+1),disque.push(disque.front()+1),book[que.front()+1]=1;
if(que.front()<k&&!book[que.front()<<1])que.push(que.front()<<1),disque.push(disque.front()+1),book[que.front()<<1]=1;
que.pop(),disque.pop();
}
}
return 0;
}