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def create(path_list):
    root = {}
    for path in path_list:
        node = root
        for name in path.rstrip("/").split("/"):
            node = node.setdefault(name, {})
    def ls(path):
        node = root
        for name in path.rstrip("/").split("/"):
            node = node.get(name, None)
            if node is None:
                return []
        return [name + "/" if children else name \
            for name, children in node.iteritems()]
    return ls

ls = create(["aaa/bbb","aaa/ccc","aaa/ddd/eee","bbb/ddd/eee"])
print ls("aaa/")
print ls("aaa/ddd/")