Exercise 3 solution

    import timeit
    from collections import deque

    N = 100_000

    def drain_list():
        jobs = list(range(N))
        while jobs:
            jobs.pop(0)

    def drain_deque():
        jobs = deque(range(N))
        while jobs:
            jobs.popleft()

    print("list ", timeit.timeit(drain_list, number=1))
    print("deque", timeit.timeit(drain_deque, number=1))

Expectation: pop(0) moves every remaining item one place, so draining the
list does work proportional to N squared overall, while popleft() is a
constant amount of work per job. The deque should win by a wide margin, and
the gap should grow if N grows. Exact seconds depend on your machine.