[USACO 2007 Ope S]Catch That Cow

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?

#include<bits/stdc++.h> int n,k,a[100001]; std::queue<int>q; int main(){ std::cin>>n>>k; q.push(n); a[n]=1; while(!a[k]){ int u=q.front(); q.pop(); if(u<=99999&&!a[u+1])a[u+1]=a[u]+1,q.push(u+1); if(u>=1&&!a[u-1])a[u-1]=a[u]+1,q.push(u-1); if(u<=50000&&!a[u*2])a[u*2]=a[u]+1,q.push(u*2); } std::cout<<a[k]-1; }

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