Js implements linked lists

Next stores attributes that point to the next node and implements js lists with objects

// The helper class generates nodes

class Node {  
    constructor(element) {
        this.element = element;
        this.next = null; }}Copy the code

Linked list operations:

• append
• getNode
• appendAt
• remove

class linkList {
    constructor() {
        this.size = 0;
        this.head = null;
    }
    append(element) {
        let node = new Node(element);
        if (this.head == null) {
            this.head = node;
        } else {
            // Find the last one according to the length
            let current = this.getNode(this.size - 1);
            current.next = node;
        }
        this.size++
    }
    getNode(index) {
            if (index < 0 || index > this.size) {
                throw new Error('error')}let current = this.head;
            for (let i = 0; i < index; i++) {
                current = current.next
            }
            return current
        }
        // Add to the specified position after the specified position
    appendAt(position, elemnt) {
            if (position < 0 || position >= this.size) {
                throw new Error('error')}let node = new Node(elemnt);
            if (position == 0) {
                node.next = this.head;
                this.head = node;
            }
            if (position < this.size) {
                let current = this.getNode(position); // Find the value at the original position
                let pre = this.getNode(position - 1);
                pre.next = node;
                let now = this.getNode(position);
                console.log(current, 'current', pre, 'pre', now); node.next = current; }}/ / remove l
    remove(position) {
            if (position < 0 || position >= this.size) {
                throw new Error('error')}let pre = this.getNode(position - 1);
            let current = this.getNode(position);
            pre.next = current.next
            this.size--
        }
        // Find the specified element
    indexof(element) {
        let current = this.head;
        for (var i = 0; i < this.size; i++) {
            if (current.element == element) {
                return i + 1;
            }
            current = current.next;
            console.log(current, '1');
        }
        return -1}}Copy the code

Unidirectional cyclic linked lists

class Node {
    constructor(element) {
        this.element = element;
        this.next = null; }}class CircularLinkedList {
    constructor() {
        this.size = 0;
        this.head = null;
    }
    append(element) { / / insert
        let node = new Node(element)
        if (this.head == null) {
            this.head = node;
            node.next = this.head;
            return;
        }
        let current = this.head;
        while(current.next ! =this.head) { // Find the last item
            current = current.next;
        }
        this.size++;
        current.next = node;
        node.next = this.head;
    }
    delete(position) { // Delete the specified location
            if (position < 0) {
                throw new Error('the error error')}if (position == 0) {
                this.head = this.head.next;
                return
            }
            let index = 0;
            let current = this.head;
            let pre;
            while (index++ < position) {
                pre = current;
                current = current.next;
            }
            pre.next = current.next;
        }
        // Gets the element at the specified position
    getNode(position) {
        let current = this.head;
        let index = 0;
        while (index++ < position) { // Find the last item
            current = current.next;
        }
        return current;
    }
    appendAt(position, element) { // Insert to the specified position
            if (position < 0) {
                throw new Error('------ error sending value ')}let index = 0;
            let pre;
            let node = new Node(element)
            let current = this.head;
            while (index++ < position) { // Find the last item
                pre = current;
                current = current.next;
            }
            pre.next = node;
            node.next = current;
            this.size++;
        }
        // Remove the specified element
    deletElement(element) {
        let current = this.head;
        let pre;
        let index = 0;
        while (index < this.size) {
            if (pre.element == element) {
                pre.next = current.next;
                this.size--
            } else{ pre = current; current = current.next; index++; }}}}let node = new CircularLinkedList();
let nodes = [1.2.3.4.5];
nodes.forEach(element= > {
    node.append(element);
});
console.dir(node, { depth: 100 });
// node.delete(0); // node.delete(2);
// console.log('----------------');
// console.dir(node, { depth: 100 });
// console.log('----------------', node.getNode(1));
// node.appendAt(1, 11)
node.deletElement(2)
console.dir(node, { depth: 100 });
Copy the code