subject ：
Enter a linked list , Output the last number in the list k Nodes . In order to conform to the habits of most people , From 1 Start counting , That is, the tail node of the list is the last 1 Nodes .
for example , A list has 6 Nodes , Start from the beginning , Their values, in turn, are 1、2、3、4、5、6. The last of the list 3 Each node has a value of 4 The node of .
Example ：
Given a linked list : 1->2->3->4->5, and k = 2.
Back to the list 4->5.
code：
# Definition for singly-linked list.
# class ListNode:
# def __init__(self, x):
# self.val = x
# self.next = None
class Solution:
def getKthFromEnd(self, head: ListNode, k: int) -> ListNode:
temp = head
n = 0
while temp:
n+=1
temp = temp.next
for _ in range(n-k):
head = head.next
return head
# Definition for singly-linked list.
# class ListNode:
# def __init__(self, x):
# self.val = x
# self.next = None
class Solution:
def getKthFromEnd(self, head: ListNode, k: int) -> ListNode:
fast, slow = head, head
for _ in range(k-1):
fast = fast.next
while fast.next != None:
fast = fast.next
slow = slow.next
return slow
