Brute force

We are searching the largest palindrome made from the product of two 3-digit numbers. Firstly, it is necessary to know when a number is a palindrome. This can be done easily using python iteration.

From solution1.py:

def is_palindrome(n):
    return str(n) == str(n)[::-1]

A better solution exists using modulus and division, but performance is not the goal here.

The range of 3-digit numbers is $[100; 999]$, the naive solution will consist in simply iterate over each number and check which product is the largest palindrome. A little trick: if $100 * 200$ does not work, $200 * 100$ won't work either, so the second loop starts from the current number of the first one.

From solution1.py:

def largest_palindrome_product():
    res = 0
    for x in range(100, 1000):
        for y in range(x, 1000):
            if x * y > res and is_palindrome(x * y):
                res = x * y

    return res