一篇很好的单调队列博客：https://www.cnblogs.com/tham/p/8038828.html

用 c++ 提交 

#include <iostream>
#include <math.h>
#include <stdlib.h>
#include <cstring>
#include <stdio.h>
#include <queue>
#include <algorithm>
#include <vector>

#define MAX 1000005
#define INF 0x3f3f3f3f

using namespace std;

typedef long long ll;

struct node{
    int x,id;
}v[MAX];

int t,n,m;
int a[MAX];
int maxn[MAX];
int minn[MAX];

void getMax(){
    int head=1,rear=0,i;
    for(i=1;i<m;i++){
        while(head<=rear && v[rear].x<=a[i])   //从后往前，小于等于当前a[i]则出队
            rear--;
        v[++rear].x=a[i];
        v[rear].id=i;
    }
    for(;i<=n;i++){
        while(head<=rear && v[rear].x<=a[i])   //从后往前，小于等于当前a[i]则出队
            rear--;
        while(head<=rear && v[head].id<=i-m)   //如果队首不在有效范围内，出队
            head++;
        v[++rear].x=a[i];
        v[rear].id=i;
        maxn[i]=v[head].x;
    }
}

void getMin(){
    int head=1;
    int rear=0;
    int i;
    for(i=1;i<m;i++){
        while(head<=rear && v[rear].x>=a[i])
            rear--;
        v[++rear].x=a[i];
        v[rear].id=i;
    }
    for(;i<=n;i++){
        while(head<=rear &&v[rear].x>=a[i])
            rear--;
        while(head<=rear && v[head].id<=i-m)
            head++;
        v[++rear].x=a[i];
        v[rear].id=i;
        minn[i]=v[head].x;
    }
}

int main(){
    scanf("%d%d",&n,&m);
        for(int i=1;i<=n;i++)
            scanf("%d",&a[i]);
        getMin();
        for(int i=m;i<=n;i++){
            if(i==n)printf("%d\n",minn[i]);
            else printf("%d ",minn[i]);
        }
        getMax();
        for(int i=m;i<=n;i++){
            if(i==n)printf("%d\n",maxn[i]);
            else  printf("%d ",maxn[i]);
        }
}