Euler Project #4.py

import unittest

def LargestIntDividesEleven(numberOfDigits):
    largestInt = 10**(numberOfDigits)-1
    return largestInt - (largestInt % 11)

def reverse(number): 
    ''' 
    This method does not speed things up, but it does provide a rather 
    interesting way of reversing any integers without converting it to 
    string first
    '''
    reversed = 0
    while number > 0:
        reversed = 10*reversed + number % 10
        number = number/10
    return reversed

def IsPalindrome(number):
    if (reverse(number) == number):
        return True
    else:
        return False

def FindLargestPalindromeProduct(numberOfDigits):
    '''
    Extremely Smart way of getting the solution!Kudo to those who come up with this
    Start by assuming P = the largest palindrome and observe its properties.
    '''
    startInt = 10**(numberOfDigits-1)
    endInt = 10**(numberOfDigits)-1
    max = 0
    i = endInt
    while ( i >= startInt):
        decrement = 1
        if (i % 11 == 0): 
            j = i
        else:
            j = LargestIntDividesEleven(numberOfDigits)
            decrement = 11
        while ( j >= startInt):
            number = i*j
            if IsPalindrome(number):
                if (max < number):
                    max = number
                else:
                    break
            j -= decrement
        i -= 1
    return max


if __name__ == '__main__':
    unittest.main(exit=False)
    print(FindLargestPalindromeProduct(3))