fix: refactor PrimMST and fix bug in PriorityQueue (#1300)

* ref: KeyPriorityQueue in separate  file #1298

* feat: add tests for KeyPriorityQueue #1298

* fix: _shiftDown refactored and corrected #1298

* fix: use KeyPriorityQueue in PrimMST #1298

* feat: add test for PrimMST #1298

* fix: format files #1298

* fix: minor coding style changes

* fix: use map for keys and priorities #1298

Data-Structures/Heap/test/KeyPriorityQueue.test.js

@@ -0,0 +1,126 @@
+import { KeyPriorityQueue } from '../KeyPriorityQueue.js'
+
+describe('Key Priority Queue', () => {
+  describe('Method isEmpty', () => {
+    test('Check heap is empty', () => {
+      const queue = new KeyPriorityQueue()
+      const res = queue.isEmpty()
+      expect(res).toEqual(true)
+    })
+
+    test('Check heap is not empty', () => {
+      const queue = new KeyPriorityQueue()
+      queue.push(0, 2)
+      const res = queue.isEmpty()
+      expect(res).toEqual(false)
+    })
+  })
+
+  describe('Methods push and pop', () => {
+    test('Test Case 1', () => {
+      // create queue
+      const queue = new KeyPriorityQueue()
+      queue.push(0, 3)
+      queue.push(1, 7)
+      queue.push(2, 9)
+      queue.push(3, 13)
+      // create expected queue
+      const expectedQueue = new KeyPriorityQueue()
+      expectedQueue.push(1, 7)
+      expectedQueue.push(3, 13)
+      expectedQueue.push(2, 9)
+      // result from popping element from the queue
+      queue.pop()
+      expect(queue).toEqual(expectedQueue)
+    })
+
+    test('Test Case 2', () => {
+      // create queue
+      const queue = new KeyPriorityQueue()
+      queue.push(0, 3)
+      queue.push(1, 9)
+      queue.push(2, 7)
+      queue.push(3, 13)
+      // create expected queue
+      const expectedQueue = new KeyPriorityQueue()
+      expectedQueue.push(2, 7)
+      expectedQueue.push(1, 9)
+      expectedQueue.push(3, 13)
+      // result from popping element from the queue
+      queue.pop()
+      expect(queue).toEqual(expectedQueue)
+    })
+
+    test('Test Case 3', () => {
+      // create queue
+      const queue = new KeyPriorityQueue()
+      queue.push(0, 3)
+      queue.push(1, 7)
+      queue.push(2, 9)
+      queue.push(3, 12)
+      queue.push(4, 13)
+      // create expected queue
+      const expectedQueue = new KeyPriorityQueue()
+      expectedQueue.push(1, 7)
+      expectedQueue.push(3, 12)
+      expectedQueue.push(2, 9)
+      expectedQueue.push(4, 13)
+      // result from popping element from the queue
+      queue.pop()
+      expect(queue).toEqual(expectedQueue)
+    })
+  })
+
+  describe('Method contains', () => {
+    test('Check heap does not contain element', () => {
+      const queue = new KeyPriorityQueue()
+      const res = queue.contains(0)
+      expect(res).toEqual(false)
+    })
+
+    test('Check heap contains element', () => {
+      const queue = new KeyPriorityQueue()
+      queue.push(0, 2)
+      const res = queue.contains(0)
+      expect(res).toEqual(true)
+    })
+  })
+
+  describe('Method update', () => {
+    test('Update without change in position', () => {
+      // create queue
+      const queue = new KeyPriorityQueue()
+      queue.push(0, 3)
+      queue.push(1, 5)
+      queue.push(2, 7)
+      queue.push(3, 11)
+      // create expected queue
+      const expectedQueue = new KeyPriorityQueue()
+      expectedQueue.push(0, 2)
+      expectedQueue.push(1, 5)
+      expectedQueue.push(2, 7)
+      expectedQueue.push(3, 11)
+      // result from updating to similar priority
+      queue.update(0, 2)
+      expect(queue).toEqual(expectedQueue)
+    })
+
+    test('Update with change in position', () => {
+      // create queue
+      const queue = new KeyPriorityQueue()
+      queue.push(0, 3)
+      queue.push(1, 5)
+      queue.push(2, 7)
+      queue.push(3, 11)
+      // create expected queue
+      const expectedQueue = new KeyPriorityQueue()
+      expectedQueue.push(1, 5)
+      expectedQueue.push(3, 11)
+      expectedQueue.push(2, 7)
+      expectedQueue.push(0, 9)
+      // result from updating to similar priority
+      queue.update(0, 9)
+      expect(queue).toEqual(expectedQueue)
+    })
+  })
+})