using System.Collections.Generic;
public static void Main()
int uniqueChars = Entropy(firstname);
double uniqueLengthRatio = (double)firstname.Length / (double)uniqueChars;
Console.WriteLine("unique: " + uniqueChars + ", length:" + firstname.Length +" , ratio: " + uniqueLengthRatio);
public static int Entropy(string s)
var hs = new HashSet<char>();