#!/usr/bin/env ruby
module Solution
  def remove_duplicates(arr)
    return arr.length if arr.length <= 1
    i = 1
    count = 1
    while i < arr.length do
      if arr[i] != arr[i-1]
        arr[count] = arr[i]
        count = count + 1
      else
        i = i + 1
      end
    end
    count
  end
end