题目：传送门
很明显，用单调队列
code:
1 #include<bits/stdc++.h>
2 using namespace std;
3 int n,k,Fmax[1000010],num[1000010],q[1000010],Fmin[1000010];
4 int a[1000010];
5 int head,tail;
6 void dmin()
7 {
8 head=1;
9 tail=0;
10 for(int i=1;i<=n;i++)
11 {
12 while(num[head]<i-k+1&&head<=tail)head++;
13 while(a[i]<q[tail]&&head<=tail)tail--;
14 num[++tail]=i;
15 q[tail]=a[i];
16 Fmin[i]=q[head];
17 }
18 }
19 void dmax()
20 {
21 head=1;
22 tail=0;
23 for(int i=1;i<=n;i++)
24 {
25 while(num[head]<i-k+1&&head<=tail)head++;
26 while(a[i]>q[tail]&&head<=tail)tail--;
27 num[++tail]=i;
28 q[tail]=a[i];
29 Fmax[i]=q[head];
30 // cout<<"i-k+1= "<<i-k+1<<endl;
31 // cout<<"i= "<<i<<endl;
32 // cout<<"num[head]= "<<num[head]<<endl;
33 // cout<<"head= "<<head<<endl;
34 // cout<<"tail= "<<tail<<endl;
35 // cout<<"num[++tail]= "<<num[++tail]<<endl;
36 // cout<<"q[tail]= "<<q[tail]<<endl;
37 // cout<<"q[head]= "<<q[head]<<endl;
38 }
39 }
40 int main()
41 {
42 cin>>n>>k;
43 for(int i=1;i<=n;i++)
44 cin>>a[i];
45 dmin();
46 dmax();
47 for(int i=k;i<n;i++)
48 cout<<Fmin[i]<<" ";
49 cout<<Fmin[n]<<endl;
50 for(int i=k;i<n;i++)
51 cout<<Fmax[i]<<" ";
52 cout<<Fmax[n]<<endl;
53 return 0;
54 }