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Commit 6ad2467

Browse files
10kartikappgurueu
andauthored
algorithm: find the middle of linked-list (#1096)
* Added Middle of linked-list implementation. * Added Middle of LL function and tests * Refactor: Added method in singly LL and its tests * Refactor: Method name and inline test calls * Use `!== null` instead of `!= null` Co-authored-by: Lars Müller <34514239+appgurueu@users.noreply.github.com>
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‎Data-Structures/Linked-List/SinglyLinkedList.js

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@@ -6,7 +6,7 @@
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* a singly linked list.
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*/
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// Methods - size, head, addLast, addFirst, addAt, removeFirst, removeLast, remove, removeAt, indexOf, isEmpty, elementAt, get, clean
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// Methods - size, head, addLast, addFirst, addAt, removeFirst, removeLast, remove, removeAt, indexOf, isEmpty, elementAt, findMiddle, get, clean
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class Node {
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constructor (data) {
@@ -193,6 +193,19 @@ class LinkedList {
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return removedNode.data
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}
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// Returns a reference to middle node of linked list
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findMiddle () {
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// If there are two middle nodes, return the second middle node.
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let fast = this.headNode
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let slow = this.headNode
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while (fast !== null && fast.next !== null) {
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fast = fast.next.next
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slow = slow.next
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}
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return slow
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}
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// make the linkedList Empty
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clean () {
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this.headNode = null

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

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@@ -164,6 +164,29 @@ describe('SinglyLinkedList', () => {
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expect(list.size()).toBe(1)
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})
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it('Middle node of linked list', () => {
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const list = new LinkedList()
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list.addFirst(1)
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// Middle node for list having single node
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expect(list.findMiddle().data).toEqual(1)
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list.addLast(2)
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list.addLast(3)
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list.addLast(4)
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list.addLast(5)
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list.addLast(6)
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list.addLast(7)
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// Middle node for list having odd number of nodes
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expect(list.findMiddle().data).toEqual(4)
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list.addLast(10)
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// Middle node for list having even number of nodes
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expect(list.findMiddle().data).toEqual(5)
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})
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it('Check Iterator', () => {
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const list = new LinkedList()
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