题目：

P2251 质量检测 - 洛谷 | 计算机科学教育新生态 (luogu.com.cn)

 

代码：

#include<iostream>
#include<cstdio>
#include<deque>
#include<vector>
typedef long long ll;
const ll N = 1e7;
using namespace std;

int main()
{
	ll n, m, i;
	cin >> n >> m;

	ll* arr = new ll[N];
	deque<ll>dp;
	for (i = 1; i <= n; i++)scanf("%lld", &arr[i]);
	for (i = 1; i <= n; i++) {
		if (!dp.empty()&&i-dp.front() >= m)dp.pop_front();
		while (!dp.empty() && arr[i] < arr[dp.back()])dp.pop_back();
		dp.push_back(i);
		if (i >= m)printf("%d\n", arr[dp.front()]);
	}
	delete[]arr;
}