ขั้นตอนการเขียนโค้ด · รุ่นลำดับทอพอโลยีของการพึ่งพา

def dependency_layers(dependencies):
    if type(dependencies) is not list or len(dependencies) > 64:
        raise ValueError("layers.input")
    count = len(dependencies)
    if any(type(row) is not set or any(type(v) is not int or not 0 <= v < count for v in row) for row in dependencies):
        raise ValueError("layers.edge")
    pending, done, layers = set(range(count)), set(), []
    while pending:
        ready = sorted(i for i in pending if dependencies[i] <= done)
        if not ready:
            raise ValueError("layers.cycle")
        layers.append(ready)
        pending.difference_update(ready)
        done.update(ready)
    return layers