Duck, Duck, Survivor

survivor.py

def survivor(count):
    if count >= 2:
        survivors = range(1, count + 1)
        start = 1
        last = survivors[-1]

        while len(survivors) > 1:
            survivors = survivors[start::2]
            start = 1 if last == survivors[-1] else 0
            last = survivors[-1]

        ret_val = survivors[0]
    else:
        ret_val = count

    return ret_val