这道题用集合也能做，真的水！

#include<bits/stdc++.h>
using namespace std;
const int maxn=2000005;
int n,k,a[maxn];
multiset<int> s;
int read(){
	int ret=0,f=1;char ch=getchar();
	while (!isdigit(ch)) {if (ch=='-')f=-f;ch=getchar();}
	while (isdigit(ch)) ret=(ret<<3)+(ret<<1)+(ch&15),ch=getchar();
	return ret*f;
}
int main(){
//	freopen("scan.in","r",stdin);
//	freopen("scan.out","w",stdout);
	n=read(),k=read();
	for(int i=1;i<=n;i++){
		a[i]=read();
		s.insert(a[i]);
		if(i>=k)printf("%d\n",*s.rbegin()),s.erase(s.find(a[i-k+1]));
	}
}