码题集OJ-捡麦子 (matiji.net)

#include<bits/stdc++.h>
using namespace std;
const int N = 1010;
int sum[N];
int ans;
int main()
{
	int n; cin >> n;
	for (int i = 1; i <= n; i++)sum[i] = i;
    
	for (int i = 1; i <= n; i++)sum[i] += sum[i - 1];

	for (int i = 1; i <= n; i++)
	{
		//cout << sum[i] << " ";
		ans += sum[i];
	}//cout << endl;

	cout << ans << endl;
	return 0;
}