java 链表的常见操作

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1.定义链表的节点类

class Node {
	protected Node next; // 下一节点
	protected String data;// 数据

	public Node(String data) {
		this.data = data;
	}

	// 显示此节点
	public void show() {
		System.out.print(data+"、");
	}
}

2.定义链表类及其操作方法

class LinkList {
	public Node first; // 定义头结点
	private int pos = 0;// 节点的位置

	public LinkList() {
		this.first = null;
	}

	// 插入一个头节点
	public void addFirstNode(String data) {
		Node node = new Node(data);
		node.next = first;
		first = node;
	}

	// 删除一个头结点,并返回头结点
	public Node deleteFirstNode() {
		Node tempNode = first;
		first = tempNode.next;
		return tempNode;
	}

	// 在任意位置插入节点 在index的后面插入
	public void add(int index, String data) {
		Node node = new Node(data);
		Node current = first;
		Node previous = first;
		while (pos != index) {
			previous = current;
			current = current.next;
			pos++;
		}
		node.next = current;
		previous.next = node;
		pos = 0;
	}

	// 删除任意位置的节点
	public Node deleteByPos(int index) {
		Node current = first;
		Node previous = first;
		while (pos != index) {
			pos++;
			previous = current;
			current = current.next;
		}
		if (current == first) {
			first = first.next;
		} else {
			pos = 0;
			previous.next = current.next;
		}
		return current;
	}

	// 根据节点的data删除节点(仅仅删除第一个)
	public Node deleteByData(String data) {
		Node current = first;
		Node previous = first; // 记住上一个节点
		while (current.data != data) {
			if (current.next == null) {
				return null;
			}
			previous = current;
			current = current.next;
		}
		if (current == first) {
			first = first.next;
		} else {
			previous.next = current.next;
		}
		return current;
	}

	// 显示出所有的节点信息
	public void displayAllNodes() {
		Node current = first;
		while (current != null) {
			current.show();
			current = current.next;
		}
		System.out.println();
	}

	// 根据位置查找节点信息
	public Node findByPos(int index) {
		Node current = first;
		if (pos != index) {
			current = current.next;
			pos++;
		}
		return current;
	}

	// 根据数据查找节点信息
	public Node findByData(String data) {
		Node current = first;
		while (current.data != data) {
			if (current.next == null)
				return null;
			current = current.next;
		}
		return current;
	}
}

3.测试链表操作：

public class Client {

	public static void main(String[] args) {
		LinkList linkList = new LinkList();
		linkList.addFirstNode("A");
		linkList.addFirstNode("B");
		linkList.addFirstNode("C");
		linkList.add(1, "D"); 
		linkList.add(2, "E");
		linkList.add(3, "F");
		linkList.displayAllNodes();
		Node node = linkList.deleteByData("A");
		System.out.println("node : " + node.data);
		linkList.displayAllNodes();
		Node node1 = linkList.findByPos(0);
		System.out.println("node1: " + node1.data);
		Node node2 = linkList.findByData("E");
		System.out.println("node2: " + node2.data);
	}
}

4.执行结果：

C、D、E、F、B、A、
node : A
C、D、E、F、B、
node: C
node: E