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GESP Level 1 2025.09_Pyramid

[Submit]

https://www.luogu.com.cn/problem/B4410

[Problem Description]

The pyramid is built with layers of stones. From the bottom to the top, each layer requires , , , , stones respectively. How many stones are needed in total to build the pyramid?

[Input Description]

A single line containing a positive integer , representing the number of layers in the pyramid.

[Output Description]

A single line containing a positive integer, representing the number of stones required to build the pyramid.

[Sample Input 1]

2

[Sample Output 1]

5

[Sample Input 2]

5

[Sample Output 2]

55

[Hint]

For all test cases, it is guaranteed that .

Reference Answer:

/*
* [GESP202509 Level 1] Pyramid
* https://www.luogu.com.cn/problem/B4410
*/
#include <iostream>

using namespace std;

int main()
{
    int n, ans = 0;
    cin >> n;
    for (int i = 1; i <= n; i++)
    {
        ans += i * i;
    }
    cout << ans << endl;
    return 0;
}

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