剑指offer：反转链表

原创

小怡情ifelse 2023-02-03 07:26:01 ©著作权

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定义一个函数，输入一个链表的头节点，反转该链表并输出反转后链表的头节点。

示例:

输入: 1->2->3->4->5->NULL
输出: 5->4->3->2->1->NULL

class LinkNode():
    def __init__(self):
        self.value = None
        self.next = None


class Solution():
    def creatLink(self) -> LinkNode:
        node1 = LinkNode()
        node1.value = 1
        node1.next = None

        node2 = LinkNode()
        node2.value = 2
        node2.next = node1

        node3 = LinkNode()
        node3.value = 3
        node3.next = node2

        return  node3


    def reverseLink(self, head:LinkNode) -> LinkNode:
        if head is None: return None
        list = []
        while(head != None):
            list.append(head)
            head = head.next

        head = list.pop()
        cur = head
        while(list):
            cur.next = list.pop()
            cur = cur.next
        cur.next = None

        return head

solu = Solution()
head = solu.creatLink()
newHead = solu.reverseLink(head)
print(newHead)