Creating Main Class

public static void Main()
{
    int[] ar = new int[]{ 3, 1, 4, 6, 5 };
    int ar_size = ar.Length;
    if (isTriplet(ar, ar_size) == true)
        Console.WriteLine("Yes");
    else
       Console.WriteLine("No");
}

isTriplet function will search for triplet can satisfies pyhtagoras equation. There are two ways to make this works. We can use brute force, or use sorting method.