Codeforces Round #267 (Div. 2) C

The new ITone 6 has been released recently and George got really keen to buy it. Unfortunately, he didn‘t have enough money, so George was going to work as a programmer. Now he faced the following problem at the work.

Given a sequence of n integers p1,?p2,?...,?pn. You are to choose k pairs of integers:

in such a way that the value of sum  is maximal possible. Help George to cope with the task.

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>


using namespace std;

long long dp[5005][5005] ;
long long a[65555] ;
long long b[65555] ;
int main()
{
	int n,m,k ;
	cin>>n>>m>>k;
	int i,j;
	for(i=1;i<=n;i++)
	{
		cin>>a[i];
		b[i] = b[i-1] + a[i] ;
	}
	for(i=1;i<=n;i++)
	{
		for(j=1;j<=k;j++)
		{
			if(i-m>=0)
			dp[i][j] = max(dp[i][j],max(dp[i-1][j],
				dp[i-m][j-1]+b[i]-b[i-m])) ;
			else dp[i][j] = max(dp[i][j],dp[i-1][j]) ;
		}
	}
	cout<<dp[n][k]<<endl;
	return 0 ;
}