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- /**
- * Refactored implementation of LinkedList (part of javascript-algorithms project) by Github users:
- * mgechev, AndriiHeonia, Microfed and Jakeh (part of javascript-algorithms project - all project contributors
- * at repository website)
- *
- * Link to repository: https://github.com/mgechev/javascript-algorithms
- */
- /**
- * Linked list node.
- *
- * @class NodeStructure
- * @util
- */
- class NodeStructure {
- constructor(data) {
- /**
- * Data of the node.
- * @member {Object}
- */
- this.data = data;
- /**
- * Next node.
- * @member {NodeStructure}
- */
- this.next = null;
- /**
- * Previous node.
- * @member {NodeStructure}
- */
- this.prev = null;
- }
- }
- /**
- * Linked list.
- *
- * @class LinkedList
- * @util
- */
- class LinkedList {
- constructor() {
- this.first = null;
- this.last = null;
- }
- /**
- * Add data to the end of linked list.
- *
- * @param {Object} data Data which should be added.
- */
- push(data) {
- const node = new NodeStructure(data);
- if (this.first === null) {
- this.first = node;
- this.last = node;
- } else {
- const temp = this.last;
- this.last = node;
- node.prev = temp;
- temp.next = node;
- }
- }
- /**
- * Add data to the beginning of linked list.
- *
- * @param {Object} data Data which should be added.
- */
- unshift(data) {
- const node = new NodeStructure(data);
- if (this.first === null) {
- this.first = node;
- this.last = node;
- } else {
- const temp = this.first;
- this.first = node;
- node.next = temp;
- temp.prev = node;
- }
- }
- /**
- * In order traversal of the linked list.
- *
- * @param {Function} callback Callback which should be executed on each node.
- */
- inorder(callback) {
- let temp = this.first;
- while (temp) {
- callback(temp);
- temp = temp.next;
- }
- }
- /**
- * Remove data from the linked list.
- *
- * @param {Object} data Data which should be removed.
- * @returns {Boolean} Returns true if data has been removed.
- */
- remove(data) {
- if (this.first === null) {
- return false;
- }
- let temp = this.first;
- let next;
- let prev;
- while (temp) {
- if (temp.data === data) {
- next = temp.next;
- prev = temp.prev;
- if (next) {
- next.prev = prev;
- }
- if (prev) {
- prev.next = next;
- }
- if (temp === this.first) {
- this.first = next;
- }
- if (temp === this.last) {
- this.last = prev;
- }
- return true;
- }
- temp = temp.next;
- }
- return false;
- }
- /**
- * Check if linked list contains cycle.
- *
- * @returns {Boolean} Returns true if linked list contains cycle.
- */
- hasCycle() {
- let fast = this.first;
- let slow = this.first;
- while (true) {
- if (fast === null) {
- return false;
- }
- fast = fast.next;
- if (fast === null) {
- return false;
- }
- fast = fast.next;
- slow = slow.next;
- if (fast === slow) {
- return true;
- }
- }
- };
- /**
- * Return last node from the linked list.
- *
- * @returns {NodeStructure} Last node.
- */
- pop() {
- if (this.last === null) {
- return null;
- }
- let temp = this.last;
- this.last = this.last.prev;
- return temp;
- };
- /**
- * Return first node from the linked list.
- *
- * @returns {NodeStructure} First node.
- */
- shift() {
- if (this.first === null) {
- return null;
- }
- const temp = this.first;
- this.first = this.first.next;
- return temp;
- };
- /**
- * Reverses the linked list recursively
- */
- recursiveReverse() {
- function inverse(current, next) {
- if (!next) {
- return;
- }
- inverse(next, next.next);
- next.next = current;
- }
- if (!this.first) {
- return;
- }
- inverse(this.first, this.first.next);
- this.first.next = null;
- const temp = this.first;
- this.first = this.last;
- this.last = temp;
- };
- /**
- * Reverses the linked list iteratively
- */
- reverse() {
- if (!this.first || !this.first.next) {
- return;
- }
- let current = this.first.next;
- let prev = this.first;
- let temp;
- while (current) {
- temp = current.next;
- current.next = prev;
- prev.prev = current;
- prev = current;
- current = temp;
- }
- this.first.next = null;
- this.last.prev = null;
- temp = this.first;
- this.first = prev;
- this.last = temp;
- };
- };
- export {NodeStructure};
- export default LinkedList;
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