Project Euler Problem 038

Statement

Take the number 192 and multiply it by each of 1, 2, and 3:

192 ร— 1 = 192
192 ร— 2 = 384
192 ร— 3 = 576

By concatenating each product we get the 1 to 9 pandigital, 192384576.
We will call 192384576 the concatenated product of 192 and (1,2,3)

The same can be achieved by starting with 9 and multiplying by 1, 2, 3, 4, and 5,
giving the pandigital, 918273645, which is the concatenated product of 9 and (1,2,3,4,5).

What is the largest 1 to 9 pandigital 9-digit number that can be formed as the
concatenated product of an integer with (1,2, … , n) where n > 1?

Solution

As there must be 2 multiplications concatenated at least the number chosen can't
be more than five digits long cause 2 multiplications would have more than 9 digits.
So I brute-forced for the first 9999 numbers:

from CommonFunctions import is_pandigital
 
if __name__ == '__main__':
    result = "0"
    for x in range(2,10000):
        tmp = str(x * 1) + str(x * 2)
        n = 3
        while len(tmp) < 9:
            tmp += str(x * n)
            n += 1
        if is_pandigital(tmp):
            result = max(int(result), int(tmp))
    print("The result is:", result)

The Python file is available for download here.

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