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Merged
akshitagupta15june merged 1 commit into from
Oct 9, 2020
Merged

Added Singly and Doubly Linked List Classes, with a bunch of methods(… #67

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116 changes: 116 additions & 0 deletions DataStructures/DoublyLinkedList.js
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Original file line number Diff line number Diff line change
@@ -0,0 +1,116 @@
class Node {
constructor(val) {
this.val = val;
this.next = null;
this.prev = null;
}
}

class DoublyLinkedList {
constructor() {
this.head = null;
this.tail = null;
this.length = 0;
}
push(val) {
var newNode = new Node(val);
if (this.length === 0) {
this.head = newNode;
this.tail = newNode;
} else {
this.tail.next = newNode;
newNode.prev = this.tail;
this.tail = newNode;
}
this.length++;
return this;
}
pop() {
if (!this.head) return undefined;
var poppedNode = this.tail;
if (this.length === 1) {
this.head = null;
this.tail = null;
} else {
this.tail = poppedNode.prev;
this.tail.next = null;
poppedNode.prev = null;
}
this.length--;
return poppedNode;
}
shift() {
if (this.length === 0) return undefined;
var oldHead = this.head;
if (this.length === 1) {
this.head = null;
this.tail = null;
} else {
this.head = oldHead.next;
this.head.prev = null;
oldHead.next = null;
}
this.length--;
return oldHead;
}
unshift(val) {
var newNode = new Node(val);
if (this.length === 0) {
this.head = newNode;
this.tail = newNode;
} else {
this.head.prev = newNode;
newNode.next = this.head;
this.head = newNode;
}
this.length++;
return this;
}
get(index) {
if (index < 0 || index >= this.length) return null;
var count, current;
if (index <= this.length / 2) {
count = 0;
current = this.head;
while (count !== index) {
current = current.next;
count++;
}
} else {
count = this.length - 1;
current = this.tail;
while (count !== index) {
current = current.prev;
count--;
}
}
return current;
}
set(index, val) {
var foundNode = this.get(index);
if (foundNode != null) {
foundNode.val = val;
return true;
}
return false;
}
insert(index, val) {
if (index < 0 || index > this.length) return false;
if (index === 0) return !!this.unshift(val);
if (index === this.length) return !!this.push(val);

var newNode = new Node(val);
var beforeNode = this.get(index - 1);
var afterNode = beforeNode.next;

(beforeNode.next = newNode), (newNode.prev = beforeNode);
(newNode.next = afterNode), (afterNode.prev = newNode);
this.length++;
return true;
}
}

var list = new DoublyLinkedList();
list.push("Harry");
list.push("Ron");
list.push("Hermione");
138 changes: 138 additions & 0 deletions DataStructures/SinglyLinkedList.js
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Original file line number Diff line number Diff line change
@@ -0,0 +1,138 @@
class Node {
constructor(val) {
this.val = val;
this.next = null;
}
}

class SinglyLinkedList {
constructor() {
this.head = null;
this.tail = null;
this.length = 0;
}
push(val) {
var newNode = new Node(val);
if (!this.head) {
this.head = newNode;
this.tail = this.head;
} else {
this.tail.next = newNode;
this.tail = newNode;
}
this.length++;
return this;
}
pop() {
if (!this.head) return undefined;
var current = this.head;
var newTail = current;
while (current.next) {
newTail = current;
current = current.next;
}
this.tail = newTail;
this.tail.next = null;
this.length--;
if (this.length === 0) {
this.head = null;
this.tail = null;
}
return current;
}
shift() {
if (!this.head) return undefined;
var currentHead = this.head;
this.head = currentHead.next;
this.length--;
if (this.length === 0) {
this.tail = null;
}
return currentHead;
}
unshift(val) {
var newNode = new Node(val);
if (!this.head) {
this.head = newNode;
this.tail = this.head;
}
newNode.next = this.head;
this.head = newNode;
this.length++;
return this;
}
get(index) {
if (index < 0 || index >= this.length) return null;
var counter = 0;
var current = this.head;
while (counter !== index) {
current = current.next;
counter++;
}
return current;
}
set(index, val) {
var foundNode = this.get(index);
if (foundNode) {
foundNode.val = val;
return true;
}
return false;
}
insert(index, val) {
if (index < 0 || index > this.length) return false;
if (index === this.length) return !!this.push(val);
if (index === 0) return !!this.unshift(val);

var newNode = new Node(val);
var prev = this.get(index - 1);
var temp = prev.next;
prev.next = newNode;
newNode.next = temp;
this.length++;
return true;
}
remove(index) {
if (index < 0 || index >= this.length) return undefined;
if (index === 0) return this.shift();
if (index === this.length - 1) return this.pop();
var previousNode = this.get(index - 1);
var removed = previousNode.next;
previousNode.next = removed.next;
this.length--;
return removed;
}
reverse() {
var node = this.head;
this.head = this.tail;
this.tail = node;
var next;
var prev = null;
for (var i = 0; i < this.length; i++) {
next = node.next;
node.next = prev;
prev = node;
node = next;
}
return this;
}
print() {
var arr = [];
var current = this.head;
while (current) {
arr.push(current.val);
current = current.next;
}
console.log(arr);
}
}

var list = new SinglyLinkedList();

list.push(100);
list.push(201);
list.push(250);
list.push(350);
list.push(999);

list.print();
1 change: 0 additions & 1 deletion DataStructures/add
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