problem-004.py

"""
Problem 4 - Largest Palindrome Product

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 is_palindrome(n: int) -> bool:
    """
    Parameters
        n (int): number to test if palindrome
    Returns
        boolean
    """

    if str(n) == str(n)[::-1]:
        return True
    return False


def largest_palindrome(low: int, high: int) -> int:
    """
    Parameters
        low (int): low integer of range
        high (int): high integer of range
    Returns
        largest_palindrome (int): largest palindrome product of
                                  values in [low, high]
    """

    largest_palindrome = 0

    for i in range(low, high):
        for j in range(low, high):
            if is_palindrome(i * j) and (i * j) > largest_palindrome:
                largest_palindrome = i * j
    return largest_palindrome


if __name__ == "__main__":
    print(
        "The largest palindrome product of three-digit numbers is: "
        + str(largest_palindrome(100, 1000))
    )