求助！！

#include<iostream>
using namespace std;
struct node{
    int pos,b;
};
int n,m;
node tmp;
node a[4000009];
int head=1,tail=0;
int main()
{
    //freopen("P1440_2.in","r",stdin);
    //freopen("tmp.out","w",stdout);
    scanf("%d%d",&n,&m);
    for (int i=1;i<=n;i++)
    {
        printf("%d\n",a[head].b);
        scanf("%d",&tmp.b);
        tmp.pos=i;
        while (head<=tail&&a[tail].b>=tmp.b)
        {
            tail--;
        }
        while (a[head].pos<=i-m)
        {
            head++;
        }
        tail++;
        a[tail].b=tmp.b;
        a[tail].pos=tmp.pos;
    }
    return 0;
}

https://www.luogu.com.cn/record/98258771

TLE*2

RE*1

WA*1