java单链表的实现及常见操作
首先简单介绍一下链表：
链表是一种最基本的数据结构，是一种线性表，是一种物理存储单元上不连续、非顺序的存储结构，但是逻辑上相连。
不需要连续的内存空间，这点和数组相反。链表分为单链表，双向链表以及循环链表之类的，这里仅讨论单链表，别问为什么，因为其他的我还没学到，hhhh～
ok，直接看代码：
public class LinkedList { private Node head; //头节点 //新增节点,在尾部新增 public void addHead(Node node) { //头节点是否存在 if (head == null) { head = node; return; } Node currentNode = head; while (currentNode.next != null) { currentNode = currentNode.next; } currentNode.next = node; } //新增节点，在头部新增 public void addTail(Node node) { node.next = head; head = node; } //删除下标为k的节点 public boolean delete(int k) { if (k < 0 || k > length() - 1) { //todo 下标越界异常处理 return false; } if (k == 0) { head = head.next; return true; } int j = 1; Node currentNode = head; Node nextNode = currentNode.next; while (j < k) { currentNode = currentNode.next; nextNode = nextNode.next; j++; } currentNode.next = nextNode.next; return true; } //查询下标为k的节点 public Node query(int k) { if (k < 0 || k > length() - 1) { return null; } if (k == 0) { return head; } Node currentNode = head; int j = 0; while (currentNode.next != null) { currentNode = currentNode.next; j++; if (j == k) { return currentNode; } } return null; } //查询链表长度 public int length() { if (head == null) { return 0; } int length = 1; Node currentNode = head; while (currentNode.next != null) { length++; currentNode = currentNode.next; } return length; } //遍历节点 public void getAllNode() { if (head == null) { return; } Node currentNode = head; System.out.print(head.data + ", "); while (currentNode.next != null) { System.out.print(currentNode.next.data + ", "); currentNode = currentNode.next; } } //在下标为k的位置插入节点 public boolean insert(int k, Node node) { if (k < 0 || k > length() - 1) { //todo 下标越界异常处理 return false; } if (k == 0) { node.next = head; head = node; return true; } Node currentNode = head; int i = 1; while (i < k) { currentNode = currentNode.next; i++; } node.next = currentNode.next; currentNode.next = node; return true; } //排序节点 public void sort() { if (head == null) { return; } Node currentNode = head; while (currentNode != null) { Node nextNode = currentNode.next; while (nextNode != null) { if (currentNode.data > nextNode.data) { int temp = currentNode.data; currentNode.data = nextNode.data; nextNode.data = temp; } nextNode = nextNode.next; } currentNode = currentNode.next; } } //链表反转，遍历法 输入原链表头节点，返回反转后链表的头节点(即原链表的尾节点) public Node reversal(Node head) { if (head == null || head.next == null) return head; Node preNode = head; //上个节点 Node currentNode = head.next; //当前节点 Node temp; //临时节点，用于保存当前节点的下一个节点 while (currentNode != null) { //假如当前节点为null，说明此时位于尾节点 temp = currentNode.next; currentNode.next = preNode; //节点指向反转 //节点向后移动 preNode = currentNode; currentNode = temp; } head.next = null; return preNode; } public static void main(String[] args) { LinkedList ll = new LinkedList(); Node node1 = new Node(10); Node node2 = new Node(20); Node node3 = new Node(30); Node node4 = new Node(40); Node node5 = new Node(50); Node node6 = new Node(60); ll.addHead(node1); ll.addHead(node2); ll.addHead(node5); ll.addHead(node3); ll.addHead(node6); ll.addHead(node4); System.out.print("排序前："); ll.getAllNode(); ll.sort(); System.out.print("\n排序后："); ll.getAllNode(); System.out.println("\n链表长度=" + ll.length()); ll.delete(2); System.out.print("\n删除下标为2的节点："); ll.getAllNode(); System.out.println("\n删除后长度=" + ll.length()); System.out.println("\n下标为0的节点=" + ll.query(0).data); Node reversal = ll.reversal(node1); //遍历反转后的链表 System.out.print("\n 反转后的链表：" +reversal.data + ", "); while (reversal.next != null) { reversal = reversal.next; System.out.print(reversal.data + ", "); } } }测试结果如下：
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文章来源: https://blog.csdn.net/qq_42815754/article/details/90270196