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The Doubly Linked List class in Javascript
Here is the complete implementation of the DoublyLinkedList Class −
Example
class DoublyLinkedList {
constructor() {
this.head = null;
this.tail = null;
this.length = 0;
}
insert(data, position = this.length) {
let node = new this.Node(data);
// List is currently empty
if (this.head === null) {
this.head = node;
this.tail = node;
this.length++;
return this.head;
}
// Insertion at head
if (position == 0) {
node.prev = null;
node.next = this.head;
this.head.prev = node;
this.head = node;
return this.head;
}
let iter = 1;
let currNode = this.head;
while (currNode.next != null && iter < position) {
currNode = currNode.next; iter++;
}
// Make new node point to next node in list
node.next = currNode.next;
// Make next node's previous point to new
node if (currNode.next != null) {
currNode.next.prev = node;
}
// Make our node point to previous node
node.prev = currNode;
// Make previous node's next point to new node
currNode.next = node;
// check if inserted element was at the tail, if yes then make tail point to it
if (this.tail.next != null) {
this.tail = this.tail.next;
}
this.length++;
return node;
}
remove(data, position = 0) {
if (this.length === 0) {
console.log("List is already empty");
return;
}
this.length--;
let currNode = this.head;
if (position <= 0) {
this.head = this.head.next;
this.head.prev = null;
} else if (position >= this.length - 1) {
this.tail = this.tail.prev;
this.tail.next = null;
} else {
let iter = 0;
while (iter < position) {
currNode = currNode.next;
iter++;
}
currNode.next = currNode.next.next;
currNode.next.prev = currNode;
}
return currNode;
}
display() {
let currNode = this.head;
while (currNode != null) {
console.log(currNode.data + " <-> ");
currNode = currNode.next;
}
}
}
DoublyLinkedList.prototype.Node = class {
constructor(data) {
this.data = data;
this.next = null;
this.prev = null;
}
};
Updated on: 15-Jun-2020
385 Views
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