经典Dp，果断记忆化……

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<iostream>
#include<functional>
using namespace std;
#define MAXN 10000 + 10
#define MAXM 500 + 10
int f[MAXN][MAXM],n,m,d[MAXN];
int dfs(int i,int j)
{
	if (i==0) return 0;
	if (f[i][j]) return f[i][j];
	if (i&&!j) f[i][j]=dfs(i-1,0);
	if (j)
		 f[i][j]=dfs(i-1,j-1)+d[i];
	else
	{
		for (int k=min(i,m);k>0;k--)
		{
	          f[i][j]=max(f[i][j],dfs(i-k,k));
		}
	}
	return f[i][j];
}
int main()
{
//	freopen("running.in","r",stdin);
	memset(f,0,sizeof(f));
	scanf("%d%d",&n,&m);
	for (int i=1;i<=n;i++) scanf("%d",&d[i]);

	printf("%dn",dfs(n,0));

//	while (1);
	return 0;
}