链表题目汇总(python3)

1、从头到尾打印链表

输入一个链表，按链表值从尾到头的顺序返回一个ArrayList。

# -*- coding:utf-8 -*-
class ListNode:
     def __init__(self, x):
         self.val = x
         self.next = None

class Solution:
    def printListFromTailToHead(self, listNode):
        l =[]
        while listNode:
            l.append(listNode.val)
            listNode = listNode.next
        return l[::-1]

2、链表中倒数第k个节点

输入一个链表，输出该链表中倒数第k个结点。

# -*- coding:utf-8 -*-
class ListNode:
    def __init__(self, x):
        self.val = x
        self.next = None

class Solution:
    def FindKthToTail(self, head, k):
        node_list = []
        while head:
            node_list.append(head)
            head = head.next
        if k < 1 or k > len(node_list):
            return
        return node_list[-k]

3、反转链表

输入一个链表，反转链表后，输出新链表的表头。

# -*- coding:utf-8 -*-
class ListNode:
    def __init__(self, x):
        self.val = x
        self.next = None

class Solution:
    def ReverseList(self, pHead):
        if pHead is None or pHead.next is None:
            return pHead
        pre = None
        cur = pHead
        while cur:
            temp = cur.next
            cur.next = pre
            pre = cur
            cur = temp
        return pre

待续...