链表问题 在单链表和双链表中删除倒数第K个节点

package com.angel.num2;
class Node{
int value;
Node next;
public Node(int value){
this.value = value;
}
}
public class DelNode {
public Node removeLastKthNode(Node head,int lastKth){
if (head == null || lastKth < 1)
return head;
Node cur = head;
while (cur != null){
lastKth--;
cur = cur.next;
}
if (lastKth == 0)
head=head.next;
if (lastKth < 0){
cur = head;
while(++lastKth != 0)
cur = cur.next;
cur.next = cur.next.next;
}
return head;
}
}

package com.angel.num2;
class DoubleNode{
int value;
DoubleNode last;
DoubleNode next;
public DoubleNode(int value){
this.value = value;
}
}
public class DoubleDel {
public DoubleNode removeLastKthNode(DoubleNode head, int lastKth){
if (head == null || lastKth < 1)
return head;
DoubleNode cur = head;
while (cur != null){
lastKth--;
cur = cur.next;
}
if (lastKth == 0){
head = head.next;
head.last=null;
}
if (lastKth < 0){
while (++lastKth != 0)
cur = cur.next;
DoubleNode newNext = cur.next.next;
cur.next = newNext;
if (newNext != null)
newNext.last = cur;
}
return head;
}
}