diff --git a/Data-Structures/Linked-List/SinglyLinkedList.js b/Data-Structures/Linked-List/SinglyLinkedList.js
index ccf3557b49..378540c2c8 100644
--- a/Data-Structures/Linked-List/SinglyLinkedList.js
+++ b/Data-Structures/Linked-List/SinglyLinkedList.js
@@ -6,7 +6,7 @@
* a singly linked list.
*/
-// Methods - size, head, addLast, addFirst, addAt, removeFirst, removeLast, remove, removeAt, indexOf, isEmpty, elementAt, get
+// Methods - size, head, addLast, addFirst, addAt, removeFirst, removeLast, remove, removeAt, indexOf, isEmpty, elementAt, get, clean
class Node {
constructor (data) {
@@ -21,6 +21,11 @@ class LinkedList {
this.length = 0
}
+ // initiates the currentNode and currentIndex and return as an object
+ initiateNodeAndIndex () {
+ return { currentNode: this.headNode, currentIndex: 0 }
+ }
+
// Returns length
size () {
return this.length
@@ -28,29 +33,32 @@ class LinkedList {
// Returns the head
head () {
- return this.headNode ? this.headNode.data : null
+ return this.headNode?.data || null
+ }
+
+ // Return if the list is empty
+ isEmpty () {
+ return this.length === 0
}
// add a node at last it to linklist
addLast (element) {
- const node = new Node(element)
-
// Check if its the first element
if (this.headNode === null) {
- this.headNode = node
- } else {
- let currentNode = this.headNode
-
- // Loop till there is a node present in the list
- while (currentNode.next) {
- currentNode = currentNode.next
- }
+ return this.addFirst(element)
+ }
+ let { currentNode } = this.initiateNodeAndIndex()
- // Adding node at the end of the list
- currentNode.next = node
+ // Loop till there is a node present in the list
+ while (currentNode.next) {
+ currentNode = currentNode.next
}
- this.length++ // Increment the length
+ const node = new Node(element)
+ // Adding node at the end of the list and increase the length
+ currentNode.next = node
+ this.length++
+ return this.size()
}
// add a node at first it to linklist
@@ -58,75 +66,72 @@ class LinkedList {
const node = new Node(element)
node.next = this.headNode
this.headNode = node
- this.length++ // Increment the length
+ this.length++
+ return this.size()
}
// remove the first from the linklist
removeFirst () {
+ const removedNode = this.headNode
if (this.length > 0) {
this.headNode = this.headNode.next
this.length--
}
+ console.log(removedNode.data)
+ return removedNode?.data
}
// remove the last from the linklist
removeLast () {
+ if (this.isEmpty()) return null
if (this.length === 1) {
- this.headNode = null
- this.length--
- } else if (this.length > 1) {
- let index = 0
- let currentNode = this.headNode
- while (index !== this.length - 2) {
- index++
- currentNode = currentNode.next
- }
-
- currentNode.next = null
- this.length--
+ return this.removeFirst()
+ }
+ let { currentIndex, currentNode } = this.initiateNodeAndIndex()
+ while (currentIndex !== this.length - 2) {
+ currentIndex++
+ currentNode = currentNode.next
}
+ const removedNode = currentNode.next
+ currentNode.next = null
+ this.length--
+ return removedNode.data
}
// Removes the node with the value as param
remove (element) {
- let currentNode = this.headNode
-
+ if (this.isEmpty()) return null
+ let { currentNode } = this.initiateNodeAndIndex()
+ let removedNode = null
// Check if the head node is the element to remove
if (currentNode.data === element) {
- this.headNode = currentNode.next
- } else {
- // Check which node is the node to remove
- while (currentNode && currentNode.next) {
- if (currentNode.next.data === element) {
- currentNode.next = currentNode.next.next
- break
- }
- currentNode = currentNode.next
+ return this.removeFirst()
+ }
+ // Check which node is the node to remove
+ while (currentNode?.next) {
+ if (currentNode.next.data === element) {
+ removedNode = currentNode.next
+ currentNode.next = currentNode.next.next
+ this.length--
+ break
}
+ currentNode = currentNode.next
}
-
- this.length-- // Decrementing the length
- }
-
- // Return if the list is empty
- isEmpty () {
- return this.length === 0
+ return removedNode?.data || null
}
// Returns the index of the element passed as param otherwise -1
indexOf (element) {
- let currentNode = this.headNode
- let index = 0
+ let { currentIndex, currentNode } = this.initiateNodeAndIndex()
while (currentNode) {
// Checking if the node is the element we are searching for
if (currentNode.data === element) {
- return index
+ return currentIndex
}
currentNode = currentNode.next
- index++
+ currentIndex++
}
-
return -1
}
@@ -135,10 +140,9 @@ class LinkedList {
if (index >= this.length || index < 0) {
throw new RangeError('Out of Range index')
}
- let currentNode = this.headNode
- let count = 0
- while (count < index) {
- count++
+ let { currentIndex, currentNode } = this.initiateNodeAndIndex()
+ while (currentIndex < index) {
+ currentIndex++
currentNode = currentNode.next
}
return currentNode.data
@@ -146,64 +150,60 @@ class LinkedList {
// Adds the element at specified index
addAt (index, element) {
- const node = new Node(element)
-
// Check if index is out of bounds of list
if (index > this.length || index < 0) {
throw new RangeError('Out of Range index')
}
+ if (index === 0) return this.addFirst(element)
+ if (index === this.length) return this.addLast(element)
+ let { currentIndex, currentNode } = this.initiateNodeAndIndex()
+ const node = new Node(element)
- let currentNode = this.headNode
- let currentIndex = 0
- // Check if index is the start of list
- if (index === 0) {
- node.next = currentNode
- this.headNode = node
- } else {
- while (currentIndex !== index - 1) {
- currentIndex++
- currentNode = currentNode.next
- }
-
- // Adding the node at specified index
- const temp = currentNode.next
- currentNode.next = node
- node.next = temp
+ while (currentIndex !== index - 1) {
+ currentIndex++
+ currentNode = currentNode.next
}
+ // Adding the node at specified index
+ const tempNode = currentNode.next
+ currentNode.next = node
+ node.next = tempNode
// Incrementing the length
this.length++
+ return this.size()
}
// Removes the node at specified index
removeAt (index) {
- let currentNode = this.headNode
- let currentIndex = 0
-
// Check if index is present in list
if (index < 0 || index >= this.length) {
throw new RangeError('Out of Range index')
}
+ if (index === 0) return this.removeFirst()
+ if (index === this.length) return this.removeLast()
- // Check if element is the first element
- if (index === 0) {
- this.headNode = currentNode.next
- } else {
- while (currentIndex !== index - 1) {
- currentIndex++
- currentNode = currentNode.next
- }
- currentNode.next = currentNode.next.next
+ let { currentIndex, currentNode } = this.initiateNodeAndIndex()
+ while (currentIndex !== index - 1) {
+ currentIndex++
+ currentNode = currentNode.next
}
-
+ const removedNode = currentNode.next
+ currentNode.next = currentNode.next.next
// Decrementing the length
this.length--
+ return removedNode.data
+ }
+
+ // make the linkedList Empty
+ clean () {
+ this.headNode = null
+ this.length = 0
}
// Method to get the LinkedList
get () {
const list = []
- let currentNode = this.headNode
+ let { currentNode } = this.initiateNodeAndIndex()
while (currentNode) {
list.push(currentNode.data)
currentNode = currentNode.next
@@ -214,7 +214,7 @@ class LinkedList {
// Method to iterate over the LinkedList
iterator () {
- let currentNode = this.headNode
+ let { currentNode } = this.initiateNodeAndIndex()
if (currentNode === null) return -1
const iterate = function * () {
diff --git a/Data-Structures/Linked-List/test/SinglyLinkedList.test.js b/Data-Structures/Linked-List/test/SinglyLinkedList.test.js
index 1b44b3e5a8..4bfde62c84 100644
--- a/Data-Structures/Linked-List/test/SinglyLinkedList.test.js
+++ b/Data-Structures/Linked-List/test/SinglyLinkedList.test.js
@@ -5,38 +5,38 @@ describe('SinglyLinkedList', () => {
const list = new LinkedList()
expect(list.get()).toEqual([])
- list.addLast(1)
+ expect(list.addLast(1)).toEqual(1)
expect(list.get()).toEqual([1])
- list.addLast(2)
- expect(list.get()).toEqual([1, 2])
+ expect(list.addLast(5)).toEqual(2)
+ expect(list.get()).toEqual([1, 5])
})
it('Check addFirst', () => {
const list = new LinkedList()
expect(list.get()).toEqual([])
- list.addFirst(1)
+ expect(list.addFirst(1)).toEqual(1)
expect(list.get()).toEqual([1])
- list.addFirst(2)
- expect(list.get()).toEqual([2, 1])
+ expect(list.addFirst(5)).toEqual(2)
+ expect(list.get()).toEqual([5, 1])
})
it('Check addAt', () => {
const list = new LinkedList()
expect(list.get()).toEqual([])
- list.addAt(0, 10)
+ expect(list.addAt(0, 10)).toEqual(1)
expect(list.get()).toEqual([10])
- list.addAt(1, 20)
+ expect(list.addAt(1, 20)).toEqual(2)
expect(list.get()).toEqual([10, 20])
- list.addAt(1, 30)
+ expect(list.addAt(1, 30)).toEqual(3)
expect(list.get()).toEqual([10, 30, 20])
- list.addAt(3, 40)
+ expect(list.addAt(3, 40)).toEqual(4)
expect(list.get()).toEqual([10, 30, 20, 40])
})
@@ -46,10 +46,10 @@ describe('SinglyLinkedList', () => {
list.addLast(2)
expect(list.get()).toEqual([1, 2])
- list.removeLast()
+ expect(list.removeLast()).toEqual(2)
expect(list.get()).toEqual([1])
- list.removeLast()
+ expect(list.removeLast()).toEqual(1)
expect(list.get()).toEqual([])
})
@@ -59,10 +59,10 @@ describe('SinglyLinkedList', () => {
list.addLast(2)
expect(list.get()).toEqual([1, 2])
- list.removeFirst()
+ expect(list.removeFirst()).toEqual(1)
expect(list.get()).toEqual([2])
- list.removeFirst()
+ expect(list.removeFirst()).toEqual(2)
expect(list.get()).toEqual([])
})
@@ -75,13 +75,13 @@ describe('SinglyLinkedList', () => {
list.addLast(50)
expect(list.get()).toEqual([10, 20, 30, 40, 50])
- list.removeAt(0)
+ expect(list.removeAt(0)).toEqual(10)
expect(list.get()).toEqual([20, 30, 40, 50])
- list.removeAt(3)
+ expect(list.removeAt(3)).toEqual(50)
expect(list.get()).toEqual([20, 30, 40])
- list.removeAt(1)
+ expect(list.removeAt(1)).toEqual(30)
expect(list.get()).toEqual([20, 40])
})
@@ -92,11 +92,11 @@ describe('SinglyLinkedList', () => {
list.addLast(30)
expect(list.get()).toEqual([10, 20, 30])
- list.remove(20)
- expect(list.get()).toEqual([10, 30])
+ expect(list.remove(10)).toEqual(10)
+ expect(list.get()).toEqual([20, 30])
- list.remove(30)
- expect(list.get()).toEqual([10])
+ expect(list.remove(100)).toEqual(null)
+ expect(list.get()).toEqual([20, 30])
})
it('Check indexOf', () => {
@@ -188,4 +188,15 @@ describe('SinglyLinkedList', () => {
count++
}
})
+ it('Cleans the linkedList', () => {
+ const list = new LinkedList()
+ list.addLast(10)
+ list.addLast(20)
+ list.addLast(30)
+ list.addLast(40)
+ list.addLast(50)
+ expect(list.size()).toEqual(5)
+ list.clean()
+ expect(list.isEmpty()).toBe(true)
+ })
})
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