STL queue

//洛谷P1886;
#include<bits/stdc++.h>
using namespace std;
const int N=1e6+10;
int a[N];
deque<int>q;
int main(){
    int n,m;
    cin>>n>>m;
    for(int i=1;i<=n;i++)   cin>>a[i];
    for(int i=1;i<=n;i++){
        while(!q.empty()&&a[q.back()]>a[i])   q.pop_back();
        q.push_back(i);
        if(i>=m){
            while(!q.empty()&&q.front()<=i-m)   q.pop_front();
            cout<<a[q.front()]<<" ";
        }
    }
    cout<<endl;
    while(!q.empty()) q.pop_front();
    for(int i=1;i<=n;i++)
    {
        while(!q.empty()&&a[q.back()]<a[i])   q.pop_back();
        q.push_back(i);
        if(i>=m){
            while(!q.empty()&&q.front()<=i-m)   q.pop_front();
            cout<<a[q.front()]<<" ";
        }
    }
    cout<<endl;
    return 0;
}