palindromes.rb

require "benchmark"

def reverse number
  inverse = 0
  while number > 0
    inverse = inverse * 10 + (number % 10)
    number = number / 10
  end
  inverse
end

def is_palindrome_1? number
  number == reverse(number)
end

def is_palindrome_2? number
  number == number.reverse
end


numbers = 1.upto(99_999_999_999).to_a
strings = 1.upto(99_999_999_999).map {|n| n.to_s}

puts Benchmark.measure {
  numbers.each do |n|
    is_palindrome_1?(Integer(n))
  end
}

puts Benchmark.measure {
  strings.each do |n|
    is_palindrome_2?(n)
  end
}

#=> 8.710000   0.010000   8.720000 (  8.711596)
#=> 2.940000   0.080000   3.020000 (  3.036482)