为什么五十啊，调了114514毫秒了

#include<iostream>
#include<cstdio>
using namespace std;
long long n,k,a[200005],dp[200005],ans=1e18,sum,h,t,q[200005];
int main(){
	cin>>n>>k;
	for(int i=1;i<=n;i++){
		scanf("%lld",&a[i]);sum+=a[i];
	}
	h=1;t=0;
	q[++t]=1;
	for(int i=2;i<=n;i++){
		while(h<=t&&q[h]+k<i)h++;
		dp[i]=dp[q[h]]+a[i];
		while(h<=t&&dp[i]<dp[q[t]])t--;
		q[++t]=i;
	}
	for(int i=n-k+1;i<=n;i++)ans=min(ans,dp[i]);
	cout<<sum-ans;
	return 0;
}