检查列表元素是否为同一列表中其他列表元素的子元素

def is_sublist(lst):
    for i in range(len(lst)):
        for j in range(len(lst)):
            if i != j and is_sublist_helper(lst[i], lst[j]):
                return True
    return False

def is_sublist_helper(sublist, lst):
    if len(sublist) > len(lst):
        return False
    for i in range(len(lst) - len(sublist) + 1):
        if sublist == lst[i:i+len(sublist)]:
            return True
    return False

# 示例用法
list1 = [1, 2, 3]
list2 = [4, 5, 6, 1, 2, 3, 7, 8, 9]
list3 = [10, 11, 12]

print(is_sublist(list1))  # 输出 True
print(is_sublist(list2))  # 输出 False
print(is_sublist(list3))  # 输出 False