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.

In [1]:

def product_gen(num):
    x = num
    y = num - 1
    
    while num < 2:
        yield x * y

In [2]:

product_gen(2)

Out[2]:

<generator object product_gen at 0x0000000003F5C1B0>

In [31]:

num1 = 999
num2 = 999
prod = None
prod_str = None
reverse_str = None
is_palindrome = False
maxpal = 0

while num1 > 2 and is_palindrome == False:
    prod = num1 * num2
    prod_str = str(prod)
    reverse_str = prod_str[::-1]
    
    if prod_str == reverse_str:
        is_palindrome = True
        
    if num2 == 99:
        num2 = 999
        num1 -= 1
    
    else:
        num2 -= 1        
print prod

In [29]:

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

In [30]:

high_pal = 0
prod = None

for x in range(999, 99, -1):
    for y in range(x, 99, -1):
        prod = x * y
        if is_palindrome(prod) and prod > high_pal:
            high_pal = prod
            
print high_pal

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