def counting_sort(array)
  counter = Array.new(100, 0)
  array.each do |num|
    counter[num] += 1
  end
  counter
end

p counting_sort([63, 25, 73, 1, 98, 73, 56, 84, 86, 57, 16, 83, 8, 25, 81, 56, 9, 53, 98, 67, 99, 12, 83, 89, 80, 91, 39, 86, 76, 85, 74, 39, 25, 90, 59, 10, 94, 32, 44, 3, 89, 30, 27, 79, 46, 96, 27, 32, 18, 21, 92, 69, 81, 40, 40, 34, 68, 78, 24, 87, 42, 69, 23, 41, 78, 22, 6, 90, 99, 89, 50, 30, 20, 1, 43, 3, 70, 95, 33, 46, 44, 9, 69, 48, 33, 60, 65, 16, 82, 67, 61, 32, 21, 79, 75, 75, 13, 87, 70, 33])
# => [0, 2, 0, 2, 0, 0, 1, 0, 1, 2, 1, 0, 1, 1, 0, 0, 2, 0, 1, 0, 1, 2, 1, 1, 1, 3, 0, 2, 0, 0, 2, 0, 3, 3, 1, 0, 0, 0, 0, 2, 2, 1, 1, 1, 2, 0, 2, 0, 1, 0, 1, 0, 0, 1, 0, 0, 2, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 2, 1, 3, 2, 0, 0, 2, 1, 2, 1, 0, 2, 2, 1, 2, 1, 2, 1, 1, 2, 2, 0, 3, 2, 1, 1, 0, 1, 1, 1, 0, 2, 2]