mod_binary_search.py

def mod_binary_search(round, previous_winner, dataset):
    # round starts at 0, previous_winner starts at 0
    if 2**round >= len(dataset):
        return previous_winner

    mod = 2 ** (round + 1)
    if test(dataset, previous_winner, mod):
        return mod_binary_search(round+1, previous_winner, dataset)
    else:
        return mod_binary_search(round+1, previous_winner + 2**round, dataset)

def test(dataset, target, modulus):
    filtered_dataset = filter(lambda x: x % modulus == target, dataset)
    if _test(filtered_dataset):
        return True
    else:
        return False