Python attempt at Problem 8, Phase II of the Dyalog APL Problem Solving Competition, 2020

balance.py

import timeit
from itertools import chain, combinations
from collections import Counter


def balance(data):
    total = sum(data)
    if total % 2:
        return None
    target = total // 2

    for subset in chain.from_iterable(combinations(data, r) for r in range(len(data) + 1)):
        if sum(subset) == target:
            return [list(subset), list((Counter(data) - Counter(subset)).elements())]

    return None

def f():
    return balance([10, 81, 98, 27, 28, 5, 1, 46, 63, 99, 25, 39, 84, 87, 76, 85, 78, 64, 41, 93])

print(timeit.timeit(f, number=3))

Runs in 40-50ms on my machine.