cs loop j Pyramids - StringBuilder

using System;
using System.Text;

public class Pyramids
{
    public static void Main()
    {
        long n = 15;//long.Parse(Console.ReadLine());//   299; //
        StringBuilder builder = new StringBuilder();
        long c = 0;
        long i = 1;
        for (; i <= n; i++)
        {
            c = c + i;
            if (c > n)
                break;
            builder.Append("1 ");
            Console.WriteLine(builder.ToString());
        }
        Console.WriteLine(i - 1);
        //Console.WriteLine(c);
        Console.ReadKey();
    }
}
/*
Coki went to Egypt once. Since then he loves pyramids. As all of us know, Coki also loves numbers...
Sooooo, the expected result is that Coki wants to make pyramids of blocks with numbers!
You have N blocks. With these blocks you should form pyramids.
Each pyramid is actually a right-angled, isosceles triangle with one cathetus on the surface (see example). Also, you can think of the triangle as a set of columns, where the leftmost is 1 and the rightmost is the highest. The Kth column has exactly K blocks on top one another.
Your task is to find the total number of full columns, given a total of N blocks
Input
Read from the standard input
On the single line, find the number N
Output
Print to the standard output
Print the number of full columns for N
Constraints
1 <= N <= 2^50^
Sample tests
Input
Copy
5
Output
Copy
2
Explanation
Copy
o
o o
o o
Input
Copy
8
Output
Copy
3
Explanation
Copy
o
o o
o o
o o o
*/