POJ-3278 Catch That Cow

#include<iostream>
#include<cstring>
#include<algorithm>
#include<cmath>
#include<cstdio>
#include<queue>
using namespace std;

struct node{
    int n,step;
    node(){};
    node(int n,int step){
        this->n=n;
        this->step=step;
    }
};

int bfs(int n,int k){
    if(!k)
        return n;
    queue<node>q;
    q.push(node(n,0));
    bool vis[100005];
    memset(vis,0,sizeof(vis));
    vis[n]=1;
    while(!q.empty()){
        node t=q.front();q.pop();
        if(t.n==k)
            return t.step;
        if(t.n>k){
            if(!vis[t.n-1]&&t.n-1>=0){
                q.push(node(t.n-1,t.step+1));
                vis[t.n-1]=1;
            }
        }
        else{
            int a=t.n-1,b=t.n+1,c=t.n*2,step=t.step+1;
            if(a>=0&&!vis[a]){
                q.push(node(a,step));
                vis[a]=1;
            }
            if(!vis[b]&&b<100005){
                q.push(node(b,step));
                vis[b]=1;
            }
            if(c<100005&&!vis[c]){
                q.push(node(c,step));
                vis[c]=1;
            }
        }
    }

}

int main(){
    int n,k;
    while(cin>>n>>k){
        cout<<bfs(n,k)<<endl;
    }
}