对嵌套列表中的元素进行计数的递归函数的大O

def count_elements(nested_list):
    count = 0
    for element in nested_list:
        if isinstance(element, list):
            count += count_elements(element)
        else:
            count += 1
    return count

# 示例使用
example_list = [1, [2, [3, 4], 5], 6, [7, 8]]
print(count_elements(example_list))  # 输出应该是8

def count_elements_iterative(nested_list):
    stack = [nested_list]
    count = 0
    while stack:
        current = stack.pop()
        for element in current:
            if isinstance(element, list):
                stack.append(element)
            else:
                count += 1
    return count