Openjudge2729 Blah数集(单调队列)

#include<iostream>
using namespace std;
int a,n,head1,head2,tail,que[1000001];
void Blah()
{
    while(1)
    {
        int x=que[head1]*2+1,y=que[head2]*3+1;
        if(x>y)que[++tail]=y,head2++;//把较小的存到队列中,较大的再参与下一轮循环
        else if(x<y)que[++tail]=x,head1++;//同理
        else if(x==y)
        {
            que[++tail]=x;
            head1++;
            head2++;
        }
        if(tail>=n){
            cout<<que[n]<<endl;
            return;
        }
    }
}
int main()
{
    while(cin>>a>>n)
    {
        head1=1,head2=1,tail=1;
        que[1]=a;
        Blah();
    }
    return 0;
}