Project Euler Problem 4 Ruby

euler4.rb

# A palindromic number reads the same both ways. The largest palindrome made from the product of two 2-digit numbers is 9009 = 91 99.
# Find the largest palindrome made from the product of two 3-digit numbers.

def looped_palindrome(num1,num2=num1)
  product = 0
  while num1 > 900
    product = num1 * num2
    return product if product.to_s == product.to_s.reverse
    if num2 > 900
       num2 -= 1
    else
      num1 -= 1
      num2 = num1 # avoids multiplying same numbers again
    end
  end
end
puts looped_palindrome(999) # => 906609

def recursive_palindrome(num1,num2=num1)
  product = num1 * num2
  return product if product.to_s == product.to_s.reverse
  if num2 > 900
    num2 -= 1
  else
    num1 -= 1
    num2 = num1 # avoids multiplying same numbers again
  end
  recursive_palindrome(num1, num2)
end
puts recursive_palindrome(999) # => 906609

def time
  start = Time.now
  yield
  puts Time.now - start
end
 
time { looped_palindrome(999) }
time { recursive_palindrome(999) }