AcWing 1089 烽火传递

#include <bits/stdc++.h>
using namespace std;

const int N = 2e5 + 10;

int n, m;
int a[N], f[N], q[N];

int main()
{
	cin >> n >> m;
	
	for (int i = 1; i <= n; i ++ ) scanf("%d", &a[i]);
	
	int hh = 0, tt = 0;
	for (int i = 1; i <= n; i ++ )
	{
		if (q[hh] < i - m) hh ++;
		f[i] = f[q[hh]] + a[i];
		while (hh <= tt && f[q[tt]] >= f[i]) tt --;
		q[ ++ tt] = i;
	}
	
	int res = INT_MAX;
	for (int i = n - m + 1; i <= n; i ++ ) res = min(res, f[i]);
	
	printf("%d", res);
	
	return 0;
}