先排个位再排十位，为什么同一个桶里的顺序不能打乱？

"""Two decimal passes, with identities preserved to expose stability."""
from itertools import product


def require(ok, message):
    if not ok:
        raise AssertionError(message)


def radix(values, break_last=False):
    if not isinstance(values, (list, tuple)) or len(values) > 1000:
        raise ValueError("at most 1000 integers required")
    if any(type(x) is not int or not 0 <= x <= 99 for x in values):
        raise ValueError("integers in 0..99 required; bool excluded")
    if type(break_last) is not bool:
        raise ValueError("break_last must be bool")
    records = [(value, index) for index, value in enumerate(values)]
    trace = [list(records)]
    for place in (1, 10):
        buckets = [[] for _ in range(10)]
        for record in records:
            buckets[record[0] // place % 10].append(record)
        # Deliberate fault: reverse ties in the MOST significant pass only.
        if break_last and place == 10:
            for bucket in buckets:
                bucket.reverse()
        records = [record for bucket in buckets for record in bucket]
        trace.append(list(records))
    return records, trace


def show(records):
    return [value for value, _ in records]


def main():
    values = [21, 12, 11, 22]
    good, trace = radix(values)
    broken, _ = radix(values, True)
    print(f"input={values}")
    print(f"after_units={show(trace[1])}")
    print(f"stable_tens={show(good)}")
    print(f"reverse_ties_in_tens={show(broken)}")
    require(show(broken) != sorted(values), "fault must be visible")
    duplicate, _ = radix([21, 12, 11, 12])
    print(f"duplicates_as_value_original_index={duplicate}")
    count = 0
    for size in range(6):
        for values in product((0, 1, 10, 11), repeat=size):
            actual, _ = radix(values)
            # Independent reference: sort the whole number, then identity.
            expected = sorted((value, i) for i, value in enumerate(values))
            require(actual == expected, "numeric order and equal-value identity")
            count += 1
    for invalid in ([True], [-1], [100], [1.5], ["11"], "11", [0] * 1001):
        try:
            radix(invalid)
        except ValueError:
            pass
        else:
            raise AssertionError("invalid input accepted")
    print(f"exhaustive_arrays={count}; invalid_inputs=7")
    print("PASS: numeric order, duplicate stability, empty input and fault witness")


if __name__ == "__main__":
    main()