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js doubly linked list

I don't know answered on July 26, 2022 Popularity 9/10 Helpfulness 4/10

answer js doubly linked list

js doubly linked list

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// Doubly linked list

function Node(val = null) {
  this.val = val;
  this.after = null;
  this.before = null;
}

function LinkedList() {
  this.head = new Node();
}

LinkedList.prototype.push = function (val) {
  if (this.head.val == null) return (this.head.val = val);
  const node = new Node(val);

  let temp = this.head;
  while (temp.after) {
    temp = temp.after;
  }
  temp.after = node;
  node.before = temp;
};

LinkedList.prototype.unshift = function (val) {
  if (this.head.val == null) return (this.head.val = val);

  const node = new Node();
  node.val = this.head.val;
  this.head.val = val;
  node.before = this.head;
  if (this.head.after) node.after = this.head.after;
  this.head.after = node;
};

LinkedList.prototype.print = function () {
  if (!this.head.after)
    return console.log(this.head.val != null ? this.head.val : "Empty");

  let temp = this.head;
  while (temp) {
    console.log(temp.val);
    temp = temp.after;
  }
};

LinkedList.prototype.pop = function () {
  if (this.head.val == null) return;
  if (!this.head.after) return (this.head.val = null);

  let temp = this.head;
  while (temp.after.after) {
    temp = temp.after;
  }
  temp.after = null;
};

LinkedList.prototype.shift = function () {
  if (this.head.val == null) return;
  if (!this.head.after) return (this.head.val = null);

  this.head = this.head.after;
  this.head.before = null;
};

const list = new LinkedList();

list.push(0);
list.unshift(1);
list.unshift(2);
list.shift();

list.print();

Popularity 9/10 Helpfulness 4/10 Language javascript

Source: Grepper

Tags: javascript linked-list

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Contributed on Jul 26 2022

I don't know

0 Answers Avg Quality 2/10

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Doubly Linked List javascript

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class DoublyLinkedList {
  constructor() {
    this.nodes = [];
  }

  get size() {
    return this.nodes.length;
  }

  get head() {
    return this.size ? this.nodes[0] : null;
  }

  get tail() {
    return this.size ? this.nodes[this.size - 1] : null;
  }

  insertAt(index, value) {
    const previousNode = this.nodes[index - 1] || null;
    const nextNode = this.nodes[index] || null;
    const node = { value, next: nextNode, previous: previousNode };

    if (previousNode) previousNode.next = node;
    if (nextNode) nextNode.previous = node;
    this.nodes.splice(index, 0, node);
  }

  insertFirst(value) {
    this.insertAt(0, value);
  }

  insertLast(value) {
    this.insertAt(this.size, value);
  }

  getAt(index) {
    return this.nodes[index];
  }

  removeAt(index) {
    const previousNode = this.nodes[index - 1] || null;
    const nextNode = this.nodes[index + 1] || null;

    if (previousNode) previousNode.next = nextNode;
    if (nextNode) nextNode.previous = previousNode;

    return this.nodes.splice(index, 1);
  }

  clear() {
    this.nodes = [];
  }

  reverse() {
    this.nodes = this.nodes.reduce((acc, { value }) => {
      const nextNode = acc[0] || null;
      const node = { value, next: nextNode, previous: null };
      if (nextNode) nextNode.previous = node;
      return [node, ...acc];
    }, []);
  }

  *[Symbol.iterator]() {
    yield* this.nodes;
  }
}

Popularity 6/10 Helpfulness 2/10 Language javascript

Source: www.30secondsofcode.org

Tags: javascript linked-list

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Contributed on Jan 09 2024

Himanshu Jangid

0 Answers Avg Quality 2/10

js doubly linked list

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