My solution of Google codegem 2017 - Problem B. Tidy Numbers

solution_b.rb

def tidy?(number)
  i = 0
  number_of_digits = number.digits.count
  while i < number_of_digits
    array = number.digits.reverse
    if (number_of_digits == 1 || i == (number_of_digits - 1 ))
      return true
    end
    if array[i] <= array[i+1]
      i += 1
    else
      return false
    end
  end
end

def the_next_number(number)
  array = number.digits.reverse
  diff = 0
  i = 0
  while i < array.length
    if (array.length == 1 || i == (array.length - 1 ))
      return number - 1
    end
    if array[i] <= array[i+1]
      i += 1
    else
      counter = 0
      while counter < (number.digits.count - (i + 1))
        diff += (10 ** (counter)) * (number.digits[counter])
        counter += 1
      end
      diff += 1
      return (number - diff)
    end
  end
end

def find_the_tidy_number(number)
  return number if tidy?(number)
  find_the_tidy_number(the_next_number(number))
end

text=File.open('B-large-practice.in').read
text.gsub!(/\r\n?/, "\n")

text.each_line.with_index do |line, index|
  if index ==0 
    num_of_row = line
  else
    open('output.txt', "a") { |f| f << "Case ##{index}: #{find_the_tidy_number(line.chomp.to_i)}\n" }   
  end
end