Circular Linked List 👻

deadcoder0904 · deadcoder0904 · commit 3441c6d7cd38 · 2017-05-21T18:16:08.000+05:30
diff --git a/examples/datastructures/circular-linked-list.js b/examples/datastructures/circular-linked-list.js
@@ -0,0 +1,55 @@
+class Node {
+	constructor(data) {
+		this.data = data;
+		this.next = null;
+	}
+}
+
+class LinkedList {
+	constructor() {
+		this.head = new Node("head");
+		this.head.next = this.head;
+	}
+
+	find(data) {
+		let temp = this.head;
+		while(temp.data != data)
+			temp = temp.next;
+		return temp;
+	}
+
+	findPrev(data) {
+		let temp = this.head;
+		while(temp.next != null && temp.next.data != data)
+			temp = temp.next;
+		return temp;
+	}
+
+	printList() {
+		let temp = this.head;
+		if(temp.next == temp)
+			return "The Linked List is Empty";
+		let str = "";
+		while(temp.next != this.head) {
+			str += temp.next.data + " -> ";
+			temp = temp.next;
+		}
+		str += this.head.next.data + "\n";
+		return str;
+	}
+
+	insertAfter(data,currData) {
+		const newNode = new Node(data);
+		let curr = this.find(currData);
+		curr.next = newNode;
+		newNode.next = this.head;
+	}
+
+	remove(data) {
+		const prev = this.findPrev(data);
+		if(prev.next != null)
+			prev.next = prev.next.next;
+	}
+}
+
+module.exports = LinkedList;
diff --git a/test/datastructures/circular-linked-list.test.js b/test/datastructures/circular-linked-list.test.js
@@ -0,0 +1,46 @@
+const expect = require('chai').expect;
+const CircularLinkedList = require('../../examples/datastructures/circular-linked-list');
+
+describe('=> CIRCULAR LINKED LIST', function() {
+	let names;
+	before(function () {
+		names = new CircularLinkedList();
+	});
+
+	it('should create an Empty Linked List', function(done) {
+		expect(names.head.data).to.equal("head");
+		done();
+	});
+
+	it('should print an Empty Linked List', function(done) {
+		expect(names.printList()).to.equal("The Linked List is Empty");
+		done();
+	});
+
+	it('should insert into a Linked List', function(done) {
+		names.insertAfter(1,"head");
+		names.insertAfter(2, 1);
+		names.insertAfter(3, 2);
+		names.insertAfter(4, 3);
+		expect(names.printList()).to.equal("1 -> 2 -> 3 -> 4 -> 1\n");
+		done();
+	});
+
+	it('should remove element from a Linked List', function(done) {
+		names.remove(1);
+		expect(names.printList()).to.equal("2 -> 3 -> 4 -> 2\n");
+		done();
+	});
+
+	describe('=> clear', function() {
+		it('should clear the Linked List', function(done) {
+			names.remove(2);
+			names.remove(3);
+			names.remove(4);
+			expect(names.printList()).to.equal("The Linked List is Empty");
+			done();
+		});
+	});
+
+});
+
