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Commit 29a3ab7

Browse files
merge: Iterator and log methods added for linked lists (#891)
* iterator, log methods added in SL * iterator, log methods added in DL * test file added for DoublyLL * format issue fix
1 parent 68ca0ce commit 29a3ab7

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5 files changed

+206
-10984
lines changed

5 files changed

+206
-10984
lines changed

‎Data-Structures/Linked-List/DoublyLinkedList.js

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@@ -194,6 +194,30 @@ function DoubleLinkedList () {
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this.getTail = function () {
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return tail
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}
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// Method to iterate over the LinkedList
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this.iterator = function () {
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let currentNode = this.getHead()
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if (currentNode === null) return -1
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const iterate = function * () {
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while (currentNode) {
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yield currentNode.element
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currentNode = currentNode.next
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}
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}
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return iterate()
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}
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// Method to log the LinkedList, for debugging
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// it' a circular structure, so can't use stringify to debug the whole structure
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this.log = function () {
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let currentNode = this.getHead()
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while (currentNode) {
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console.log(currentNode.element)
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currentNode = currentNode.next
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}
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}
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}
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// Example
@@ -202,5 +226,9 @@ function DoubleLinkedList () {
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// newDoubleLinkedList.append(1)
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// newDoubleLinkedList.append(2)
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// newDoubleLinkedList.size() // returns 2
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// const iterate = newDoubleLinkedList.iterator()
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// console.log(iterate.next().value) // 1
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// console.log(iterate.next().value) // 2
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// console.log(newDoubleLinkedList.log())
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export { DoubleLinkedList }

‎Data-Structures/Linked-List/SinglyLinkedList.js

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@@ -211,6 +211,25 @@ class LinkedList {
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return list
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}
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// Method to iterate over the LinkedList
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iterator () {
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let currentNode = this.headNode
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if (currentNode === null) return -1
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const iterate = function * () {
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while (currentNode) {
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yield currentNode.data
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currentNode = currentNode.next
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}
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}
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return iterate()
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}
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// Method to log the LinkedList
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log () {
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console.log(JSON.stringify(this.headNode, null, 2))
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}
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}
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export { Node, LinkedList }
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@@ -0,0 +1,127 @@
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import { DoubleLinkedList } from '../DoublyLinkedList'
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describe('DoubleLinkedList', () => {
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it('Check append', () => {
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const list = new DoubleLinkedList()
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list.append(1)
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expect(list.getHead().element).toEqual(1)
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list.append(2)
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expect(list.getTail().element).toEqual(2)
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})
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it('Check insert', () => {
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const list = new DoubleLinkedList()
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list.insert(0, 1)
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expect(list.getHead().element).toEqual(1)
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list.insert(1, 20)
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expect(list.getTail().element).toEqual(20)
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})
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it('Check removeAt', () => {
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const list = new DoubleLinkedList()
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list.insert(0, 10)
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list.insert(1, 40)
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list.insert(2, 30)
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list.removeAt(0)
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expect(list.getHead().element).toEqual(40)
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list.removeAt(1)
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expect(list.getTail().element).toEqual(40)
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})
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it('Check delete', () => {
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const list = new DoubleLinkedList()
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list.insert(0, 10)
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list.insert(1, 40)
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list.delete(10)
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expect(list.getHead().element).toEqual(40)
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})
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it('Check deleteTail', () => {
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const list = new DoubleLinkedList()
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list.insert(0, 10)
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list.insert(1, 40)
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list.deleteTail()
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expect(list.getTail().element).toEqual(10)
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})
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it('Check toString', () => {
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const list = new DoubleLinkedList()
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list.insert(0, 20)
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expect(list.toString()).toEqual('20')
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})
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it('Check isEmpty', () => {
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const list = new DoubleLinkedList()
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expect(list.isEmpty()).toEqual(true)
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list.insert(0, 'Hello')
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expect(list.isEmpty()).toEqual(false)
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})
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it('Check size', () => {
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const list = new DoubleLinkedList()
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expect(list.size()).toBe(0)
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list.append(10)
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expect(list.size()).toBe(1)
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list.removeAt(1)
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expect(list.size()).toBe(1)
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})
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it('Check toArray', () => {
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const list = new DoubleLinkedList()
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list.append(1)
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list.append(2)
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const listArray = list.toArray()
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expect(listArray).toEqual([1, 2])
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})
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it('Check getHead', () => {
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const list = new DoubleLinkedList()
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expect(list.getHead()).toEqual(null)
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list.append(1)
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list.append(2)
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expect(list.getHead()).toBeInstanceOf(Object)
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})
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it('Check Iterator', () => {
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const list = new DoubleLinkedList()
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let iterate = list.iterator()
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expect(iterate).toBe(-1)
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const arr = [10, 20, 5]
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list.append(arr[0])
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list.append(arr[1])
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list.append(arr[2])
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iterate = list.iterator()
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for (let i = 0; i < arr.length; i++) {
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expect(iterate.next().value).toBe(arr[i])
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}
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expect(iterate.next().value).toBe(undefined)
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iterate = list.iterator()
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let count = 0
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for (const item of iterate) {
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expect(item).toBe(arr[count])
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count++
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}
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})
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})

‎Data-Structures/Linked-List/test/SinglyLinkedList.test.js

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@@ -163,4 +163,29 @@ describe('SinglyLinkedList', () => {
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list.removeFirst()
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expect(list.size()).toBe(1)
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})
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it('Check Iterator', () => {
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const list = new LinkedList()
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let iterate = list.iterator()
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expect(iterate).toBe(-1)
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const arr = [10, 20, 5]
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list.addLast(arr[0])
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list.addLast(arr[1])
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list.addLast(arr[2])
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iterate = list.iterator()
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for (let i = 0; i < arr.length; i++) {
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expect(iterate.next().value).toBe(arr[i])
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}
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expect(iterate.next().value).toBe(undefined)
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iterate = list.iterator()
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let count = 0
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for (const item of iterate) {
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expect(item).toBe(arr[count])
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count++
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}
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})
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})

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