BFS/poj 3278 Catch That Cow

#include<cstdio>
#include<queue>
#include<cstring>
using namespace std;
const int MAXN=200010;
int n,k;
bool v[MAXN];
struct point
{
    int x;
    int step;
};
int bfs()
{
    memset(v,0,sizeof(v));
    queue<point>que;
    point now,next;
    now.x=n;
    now.step=0;
    v[n]=1;
    que.push(now);

    while (!que.empty())
    {
        now=que.front();
        que.pop();
        if (now.x==k) break;

        next.x=now.x+1;
        if (next.x>=0 && next.x<=MAXN && !v[next.x])
        {
            v[next.x]=1;
            next.step=now.step+1;
            que.push(next);
        }

        next.x=now.x-1;
        if (next.x>=0 && next.x<=MAXN && !v[next.x])
        {
            v[next.x]=1;
            next.step=now.step+1;
            que.push(next);
        }

        next.x=now.x*2;
        if (next.x>=0 && next.x<=MAXN && !v[next.x])
        {
            v[next.x]=1;
            next.step=now.step+1;
            que.push(next);
        }

    }
    return now.step;
}

int main()
{
    while (scanf("%d%d",&n,&k)!=EOF)
    {
        printf("%d\n",bfs());
    }
    return 0;
}