Electricity

/*
    Task    : _example
    Author  : Phumipat C. [MAGCARI]
    Language: C++
    Created : 11 December 2022 [11:09]
*/
#include<bits/stdc++.h>
using namespace std;
struct A{
    int l,id;
    bool operator < (const A&o) const{
        return l>o.l;
    }
};
priority_queue<A > heap;
int dp[500010];
int main(){
    int n,k;
    scanf("%d %d %d",&n,&k,&dp[1]);
    heap.push({dp[1],1});
    for(int i=2;i<=n;i++){
        scanf("%d",&dp[i]);
        while(!heap.empty() && i-heap.top().id>k)   heap.pop();
        dp[i]+=heap.top().l;
        heap.push({dp[i],i});
    }
    printf("%d\n",dp[n]);
    return 0;
}