js 链表结构体

class Node {
    constructor(data) {
        this.data = data;
        this.next = null;
    }
}

class LinkedList {
    constructor() {
        this.head = null;
        this.size = 0;
    }

    // 在链表末尾添加节点
    add(data) {
        const node = new Node(data);
        if (this.head === null) {
            this.head = node;
        } else {
            let current = this.head;
            while (current.next !== null) {
                current = current.next;
            }
            current.next = node;
        }
        this.size++;
    }

    // 在指定位置插入节点
    insertAt(data, index) {
        if (index < 0 || index > this.size) {
            return console.log("索引超出范围");
        }
        const node = new Node(data);
        let current = this.head;
        let previous;
        let count = 0;

        if (index === 0) {
            node.next = current;
            this.head = node;
        } else {
            while (count < index) {
                previous = current;
                current = current.next;
                count++;
            }
            node.next = current;
            previous.next = node;
        }
        this.size++;
    }

    // 移除指定位置的节点
    removeAt(index) {
        if (index < 0 || index >= this.size) {
            return console.log("索引超出范围");
        }
        let current = this.head;
        if (index === 0) {
            this.head = current.next;
        } else {
            let previous = null;
            let count = 0;
            while (count < index) {
                previous = current;
                current = current.next;
                count++;
            }
            previous.next = current.next;
        }
        this.size--;
        return current.data;
    }

    // 打印链表
    printList() {
        let current = this.head;
        let str = "";
        while (current) {
            str += current.data + " ";
            current = current.next;
        }
        console.log(str);
    }
}

// 使用示例
const list = new LinkedList();
list.add(1);
list.add(2);
list.add(3);
list.insertAt(4, 1);
list.printList(); // 输出: 1 4 2 3
list.removeAt(2);
list.printList(); // 输出: 1 4 3