1、B站视频链接：E44 单调队列优化DP 修剪草坪_哔哩哔哩_bilibili

#include <bits/stdc++.h> 
using namespace std;
typedef long long LL;
const int N=1e5+10;
int n,k,q[N];
LL w[N],f[N],sum;

int main(){
  cin>>n>>k; k++; //
  for(int i=1;i<=n;i++){
  	cin>>w[i];
  	sum+=w[i];
  }
  
  int h=1,t=0;LL ans=1e18;
  for(int i=1;i<=n;i++){
    while(h<=t && f[q[t]]>=f[i-1]) t--;
    q[++t]=i-1;
    if(q[h]<i-k) h++;
    f[i]=f[q[h]]+w[i];
    if(i>n-k) ans=min(ans,f[i]);
  }
  cout<<sum-ans;
}