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RemoveLastKthNode.java
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RemoveLastKthNode.java
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package com.camnter.basicexercises.linklist;
import com.camnter.basicexercises.core.Node;
/**
* 删除链表中倒数第 K 个节点
* <p/>
* 一趟遍历头到尾,每次都 K--
* 如果
* K < 0。在一趟遍历,++K 判断 是否为 0,不为 0,继续 next 走,此时 cur 要删除的节点的 前一个节点
* K > 0,没有这个节点的,脏数据,不处理
* K = 0,就是头结点,remove head
*
* @author CaMnter
*/
public class RemoveLastKthNode<T> {
public Node<T> removeLastKthNode(Node<T> head, int lastKth) {
if (head == null || lastKth < 1) {
return head;
}
Node<T> cur = head;
while (cur != null) {
lastKth--;
cur = cur.next;
}
if (lastKth == 0) {
// 删除头节点
head = head.next;
}
if (lastKth < 0) {
cur = head;
while (++lastKth != 0) {
cur = cur.next;
}
/**
* 因为之前是 ++lastKth 判断
* 此时 cur 要删除的节点的 前一个节点
* 删除 cur.next
*/
cur.next = cur.next.next;
}
return head;
}
public static void main(String[] args) {
RemoveLastKthNode<Integer> removeLastKthNode = new RemoveLastKthNode<Integer>();
/**
* 1 2 3 4 5 6
* 删除倒第 4 个
* 1 2 4 5 6
*/
Node.printLinkList(removeLastKthNode.removeLastKthNode(Node.getLinkList(), 4));
}
}