自定义链表实现反转链表

描述：
输入123456
输出654321

利用堆栈实现链表反转

a=[]
a.append(1)
a.append(2)
a.append(3)
a.append(4)
while(a):
	print(a.pop())

自定义链表

class node():
    def __init__(self, elem, next=None):
        if isinstance(elem, int):
            self.elem = elem
            self.next = next
        elif isinstance(elem, list):
            self.elem = elem[0]
            self.next = None
            curr = self
            for i in range(1, len(elem)):
                pre = node(elem[i])
                curr.next = pre
                curr = curr.next
   
        def chain_reverse(curr):
        if curr == None or curr.next == None:
            return curr
        # 先初始化
        pre = None
        next = None
        while (curr != None):
            # 为使得链表不断裂 需要保存相关节点
            next = curr.next# 保存链表结构
            curr.next = pre# 改变链表方向 ，反转链表
            pre = curr
            # 依次处理后面的链表

            curr = next

        return pre

if __name__ == '__main__':
    # 创建链表  单个元素
    L = node(1)
    L.next = node(2)
    L.next.next = node(3)
    L.next.next.next = node(4)

    res = node.chain_reverse(L)
    print(res.elem, res.next.elem, res.next.next.elem, res.next.next.next.elem)
   #4321
    while res:
        print(res.elem,end=' ')
        res = res.next
    #4321
    print()
    # lista=[1,2,3,4,5,6]
    lista = [1, 2, 3, 4, 5, 6]
    # 创建链表
    List_a = node(lista)
    # 反转链表
    res1 = node.chain_reverse(List_a)
    while res1:
        print(res1.elem,end=' ')
        res1 = res1.next
     #654321