def count_zeros arr
  run = true
  count = 0
  temp = ""
  while run
    if arr[count].nil?
      temp = ""
      run = false
    elsif !(arr[count] == "1")
      temp += arr[count]
    else
      run = false
    end
    count += 1
  end

  temp.size
end

def binary_gap num
  result = []
  temp = num.to_s(2).split('')
  temp.each_with_index do |x, i|
    if x == "1"
      result << count_zeros(temp[i+1..-1])
    end
  end
  result.max
end