Commit bd15e6e

authored

Merge pull request knaxus#20 from ulasaydin/master

Added Reverse Linked List Problem.

2 parents aae5ade + dd2c796 commit bd15e6eCopy full SHA for bd15e6e

File tree

+53

-0

lines changed

README.md
src/_DataStructures_/LinkedList/reverse-linked-list
- index.js
- reverse-linked-list.test.js

+53

-0

lines changed

Lines changed: 1 addition & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -17,6 +17,7 @@ Collection of interview questions with Unit Tests. Problems includes Data Struct`
`17`	`17`	`- [N Element From Last](src/_DataStructures_/LinkedList/element-from-last)`
`18`	`18`	`- [Middle Node](src/_DataStructures_/LinkedList/middle-node)`
`19`	`19`	`- [Detect Loop](src/_DataStructures_/LinkedList/loop-in-list)`
	`20`	`+ - [Reverse Linked List](src/_DataStructures_/LinkedList/reverse-linked-list)`
`20`	`21`	`- [Stack](src/_DataStructures_/Stack)`
`21`	`22`	`- [Implement Queue Using Stack](src/_DataStructures_/Stack/immitate-queue-using-stack)`
`22`	`23`	`- [Baseball Game](src/_DataStructures_/Stack/baseball-game)`

Lines changed: 15 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,15 @@`
	`1`	`+function reverseLinkedList(linkedList) {`
	`2`	`+ let next = linkedList.getFirst();`
	`3`	`+ let current = null;`
	`4`	`+ let prev;`
	`5`	`+ while(next != null){`
	`6`	`+ prev = current;`
	`7`	`+ current = next;`
	`8`	`+ next = next.next;`
	`9`	`+ current.next = prev;`
	`10`	`+ }`
	`11`	`+ return current;`
	`12`	`+};`
	`13`	`+module.exports = {`
	`14`	`+ reverseLinkedList,`
	`15`	`+ };`

Lines changed: 37 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,37 @@`
	`1`	`+const { LinkedList } = require('../index');`
	`2`	`+const { reverseLinkedList } = require('.');`
	`3`	`+`
	`4`	`+describe('Reverse a LinkedList', () => {`
	`5`	`+ let list = null;`
	`6`	`+ beforeEach(() => {`
	`7`	`+ list = new LinkedList();`
	`8`	`+ list.addAtBeginning('1');`
	`9`	`+ list.addAtEnd('2');`
	`10`	`+ list.addAtEnd('3');`
	`11`	`+ list.addAtEnd('4');`
	`12`	`+ list.addAtEnd('5');`
	`13`	`+ });`
	`14`	`+`
	`15`	+ it('Should return `null` for empty list', () => {
	`16`	`+ list.delete();`
	`17`	`+ expect(reverseLinkedList(list)).toEqual(null);`
	`18`	`+ });`
	`19`	`+`
	`20`	+ it('Should return `5`->`4`->`3`->`2`->`1` for the given list', () => {
	`21`	`+ let reversedList = reverseLinkedList(list);`
	`22`	`+ expect(reversedList.data).toEqual('5');`
	`23`	`+ expect(reversedList.next.data).toEqual('4');`
	`24`	`+ expect(reversedList.next.next.data).toEqual('3');`
	`25`	`+ expect(reversedList.next.next.next.data).toEqual('2');`
	`26`	`+ expect(reversedList.next.next.next.next.data).toEqual('1');`
	`27`	`+ });`
	`28`	`+`
	`29`	+ it('Should return `3`->`2`->`1` after deleting 2 last nodes of the list', () => {
	`30`	`+ list.removeFromEnd();`
	`31`	`+ list.removeFromEnd();`
	`32`	`+ let reversedList2 = reverseLinkedList(list);`
	`33`	`+ expect(reversedList2.data).toEqual('3');`
	`34`	`+ expect(reversedList2.next.data).toEqual('2');`
	`35`	`+ expect(reversedList2.next.next.data).toEqual('1');`
	`36`	`+ });`
	`37`	`+});`

Comments

(0)