删除单链表和双向链表倒数第k个节点

注释：当从链表第一个开始读，直到读到最后一个，让k不断地减一。k>0说明没什么可以删的，返回head即可，k=0，说明删头节点，k>0时，再从头开始读，k逐渐+1，直到k=0，那个便是要删除的前一个节点

public class Node {
    public int vaule;
    public Node next;

    public Node(int data){
        vaule=data;
    }
}

public static 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;
    }

双向链表：

public class DoubleNode {
    public int vaule;
    public DoubleNode last;
    public DoubleNode next;

    public DoubleNode(int data){
        vaule=data;
    }
}

 public static 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){
            cur=head;
            while (++lastKth!=0){
                cur=cur.next;
            }
            DoubleNode newNext=cur.next.next;
            cur.next=newNext;
            if(newNext!=null){
                newNext.last=cur;
            }
        }
        return head;
    }