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  1. Waiter
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Waiter

  • alexander_zawad1
     + 0 comments

    As usual, when you see the completion percentage for a question go below 90% you can suspect that it's going to be a bit nasty...

    This problem has two parts: generating the first 'q' primes, and then doing the plate sorting/stacking.

    Python 3:

    def eratosthenes():
    from collections import defaultdict
    composites = defaultdict(list)
    x = 2
    while True:
        if x in composites:
            for c in composites[x]:
                composites[c+x].append(c)
            del composites[x]
        else:
            yield x
            composites[x*x] = [x]
        x += 1

def waiter(number, q):
    plates = number
    answers = []
    primes = eratosthenes()
    for _ in range(q):
        A = []
        B = []
        prime = next(primes)
        while plates:
            plate = plates.pop()
            if plate % prime == 0:
                B.append(plate)
            else:
                A.append(plate)
        answers.extend(reversed(B))
        plates = A
    answers.extend(reversed(A))
    return answers