题解 | #链表中倒数最后k个结点#

#     def __init__(self, x):
#         self.val = x
#         self.next = None
#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# 
# @param pHead ListNode类 
# @param k int整型 
# @return ListNode类
#
class Solution:
    def FindKthToTail(self , pHead: ListNode, k: int) -> ListNode:
        if not pHead:
            return None
        pre = pHead
        cur = pHead
        while k:
            if not cur:
                return None
            else:
                cur = cur.next
            k -= 1
        
        while cur:
            pre = pre.next
            cur = cur.next
        return pre