HDU_2717_Catch That Cow

很短的 BFS 队列

HDU_2717_Catch That Cow

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

int book[100005<<1]={0};
int que[100005<<1];
int n,k;
int main()
{
    cin>>n>>k;
    queue<int>q;
    que[n]=0;
    book[n]=1;
    q.push(n);
    while(!q.empty())
    {
        int a=q.front();
        q.pop();
        if(a-1>=0 && !book[a-1])
        {
            book[a-1]=1;
            que[a-1]=que[a]+1;
            q.push(a-1);
        }
        if(a+1<=2*k && !book[a+1])
        {
            book[a+1]=1;
            que[a+1]=que[a]+1;
            q.push(a+1);
        }
        if(a*2<=2*k && !book[a*2])
        {
            book[a*2]=1;
            que[a*2]=que[a]+1;
            q.push(a*2);
        }
    }
    cout<<que[k]<<endl;
}