diff --git a/src/data-structures/graph/abstract-graph.ts b/src/data-structures/graph/abstract-graph.ts
index 4a0931d..3b0be52 100644
--- a/src/data-structures/graph/abstract-graph.ts
+++ b/src/data-structures/graph/abstract-graph.ts
@@ -691,7 +691,7 @@ export abstract class AbstractGraph<
       if (vertexOrKey instanceof AbstractVertex) distMap.set(vertexOrKey, Infinity);
     }
 
-    const heap = new PriorityQueue<{ key: number; value: VO }>({ comparator: (a, b) => a.key - b.key });
+    const heap = new PriorityQueue<{ key: number; value: VO }>([], { comparator: (a, b) => a.key - b.key });
     heap.add({ key: 0, value: srcVertex });
 
     distMap.set(srcVertex, 0);
diff --git a/src/data-structures/heap/heap.ts b/src/data-structures/heap/heap.ts
index 3e1eca2..55b52e3 100644
--- a/src/data-structures/heap/heap.ts
+++ b/src/data-structures/heap/heap.ts
@@ -6,13 +6,32 @@
  */
 
 import type { Comparator, DFSOrderPattern } from '../../types';
+import { HeapOptions } from "../../types";
 
 export class Heap<E = any> {
-  constructor(options: { comparator: Comparator<E>; elements?: E[] }) {
-    this._comparator = options.comparator;
-    if (options.elements && options.elements.length > 0) {
-      this._elements = options.elements;
-      this.fix();
+  options: HeapOptions<E>;
+
+  constructor(elements?: Iterable<E>, options?: HeapOptions<E>) {
+    const defaultComparator = (a: E, b: E) => {
+      if (!(typeof a === 'number' && typeof b === 'number')) {
+        throw new Error('The a, b params of compare function must be number');
+      } else {
+        return a - b;
+      }
+    }
+    if (options) {
+      this.options = options
+    } else {
+      this.options = {
+        comparator: defaultComparator
+      }
+    }
+
+    if (elements) {
+      for (const el of elements) {
+        this.push(el);
+      }
+      // this.fix();
     }
   }
 
@@ -22,12 +41,6 @@ export class Heap<E = any> {
     return this._elements;
   }
 
-  protected _comparator: Comparator<E>;
-
-  get comparator(): Comparator<E> {
-    return this._comparator;
-  }
-
   /**
    * Get the size (number of elements) of the heap.
    */
@@ -46,10 +59,11 @@ export class Heap<E = any> {
   /**
    * Static method that creates a binary heap from an array of elements and a comparison function.
    * @returns A new Heap instance.
+   * @param elements
    * @param options
    */
-  static heapify<E>(options: { elements: E[]; comparator: Comparator<E> }): Heap<E> {
-    return new Heap<E>(options);
+  static heapify<E>(elements: Iterable<E>, options: { comparator: Comparator<E> }): Heap<E> {
+    return new Heap<E>(elements, options);
   }
 
   /**
@@ -283,7 +297,7 @@ export class Heap<E = any> {
    * @returns A new Heap instance containing the same elements.
    */
   clone(): Heap<E> {
-    const clonedHeap = new Heap<E>({ comparator: this.comparator });
+    const clonedHeap = new Heap<E>([], this.options);
     clonedHeap._elements = [...this.elements];
     return clonedHeap;
   }
@@ -340,7 +354,7 @@ export class Heap<E = any> {
   }
 
   filter(predicate: (element: E, index: number, heap: Heap<E>) => boolean): Heap<E> {
-    const filteredHeap: Heap<E> = new Heap<E>({ comparator: this.comparator });
+    const filteredHeap: Heap<E> = new Heap<E>([], this.options);
     let index = 0;
     for (const el of this) {
       if (predicate(el, index, this)) {
@@ -353,7 +367,7 @@ export class Heap<E = any> {
 
   map<T>(callback: (element: E, index: number, heap: Heap<E>) => T, comparator: Comparator<T>): Heap<T> {
 
-    const mappedHeap: Heap<T> = new Heap<T>({ comparator: comparator });
+    const mappedHeap: Heap<T> = new Heap<T>([], { comparator: comparator });
     let index = 0;
     for (const el of this) {
       mappedHeap.add(callback(el, index, this));
@@ -380,6 +394,15 @@ export class Heap<E = any> {
    * Space Complexity: O(1)
    */
 
+  print(): void {
+    console.log([...this]);
+  }
+
+  /**
+   * Time Complexity: O(n)
+   * Space Complexity: O(1)
+   */
+
   /**
    * Time Complexity: O(log n)
    * Space Complexity: O(1)
@@ -392,18 +415,13 @@ export class Heap<E = any> {
     while (index > 0) {
       const parent = (index - 1) >> 1;
       const parentItem = this.elements[parent];
-      if (this._comparator(parentItem, element) <= 0) break;
+      if (this.options.comparator(parentItem, element) <= 0) break;
       this.elements[index] = parentItem;
       index = parent;
     }
     this.elements[index] = element;
   }
 
-  /**
-   * Time Complexity: O(n)
-   * Space Complexity: O(1)
-   */
-
   /**
    * Time Complexity: O(log n)
    * Space Complexity: O(1)
@@ -420,12 +438,12 @@ export class Heap<E = any> {
       let minItem = this.elements[left];
       if (
         right < this.elements.length &&
-        this._comparator(minItem, this.elements[right]) > 0
+        this.options.comparator(minItem, this.elements[right]) > 0
       ) {
         left = right;
         minItem = this.elements[right];
       }
-      if (this._comparator(minItem, element) >= 0) break;
+      if (this.options.comparator(minItem, element) >= 0) break;
       this.elements[index] = minItem;
       index = left;
     }
@@ -452,7 +470,7 @@ export class FibonacciHeapNode<E> {
 export class FibonacciHeap<E> {
   constructor(comparator?: Comparator<E>) {
     this.clear();
-    this._comparator = comparator || this.defaultComparator;
+    this._comparator = comparator || this._defaultComparator;
 
     if (typeof this.comparator !== 'function') {
       throw new Error('FibonacciHeap constructor: given comparator should be a function.');
@@ -653,7 +671,7 @@ export class FibonacciHeap<E> {
       this._root = undefined;
     } else {
       this._min = z.right;
-      this.consolidate();
+      this._consolidate();
     }
 
     this._size--;
@@ -705,27 +723,27 @@ export class FibonacciHeap<E> {
     heapToMerge.clear();
   }
 
+  /**
+   * Create a new node.
+   * @param element
+   * @protected
+   */
+  createNode(element: E): FibonacciHeapNode<E> {
+    return new FibonacciHeapNode<E>(element);
+  }
+
   /**
    * Default comparator function used by the heap.
    * @param {E} a
    * @param {E} b
    * @protected
    */
-  protected defaultComparator(a: E, b: E): number {
+  protected _defaultComparator(a: E, b: E): number {
     if (a < b) return -1;
     if (a > b) return 1;
     return 0;
   }
 
-  /**
-   * Create a new node.
-   * @param element
-   * @protected
-   */
-  protected createNode(element: E): FibonacciHeapNode<E> {
-    return new FibonacciHeapNode<E>(element);
-  }
-
   /**
    * Time Complexity: O(1)
    * Space Complexity: O(1)
@@ -782,7 +800,7 @@ export class FibonacciHeap<E> {
    * @param x
    * @protected
    */
-  protected link(y: FibonacciHeapNode<E>, x: FibonacciHeapNode<E>): void {
+  protected _link(y: FibonacciHeapNode<E>, x: FibonacciHeapNode<E>): void {
     this.removeFromRoot(y);
     y.left = y;
     y.right = y;
@@ -803,7 +821,7 @@ export class FibonacciHeap<E> {
    * Remove and return the top element (smallest or largest element) from the heap.
    * @protected
    */
-  protected consolidate(): void {
+  protected _consolidate(): void {
     const A: (FibonacciHeapNode<E> | undefined)[] = new Array(this.size);
     const elements = this.consumeLinkedList(this.root);
     let x: FibonacciHeapNode<E> | undefined,
@@ -824,7 +842,7 @@ export class FibonacciHeap<E> {
           y = t;
         }
 
-        this.link(y, x);
+        this._link(y, x);
         A[d] = undefined;
         d++;
       }
diff --git a/src/data-structures/heap/max-heap.ts b/src/data-structures/heap/max-heap.ts
index 9b90701..a0462ea 100644
--- a/src/data-structures/heap/max-heap.ts
+++ b/src/data-structures/heap/max-heap.ts
@@ -7,11 +7,12 @@
  */
 
 import { Heap } from './heap';
-import type { Comparator } from '../../types';
+import type { HeapOptions } from '../../types';
 
 export class MaxHeap<E = any> extends Heap<E> {
   constructor(
-    options: { comparator: Comparator<E>; nodes?: E[] } = {
+    elements?: Iterable<E>,
+    options: HeapOptions<E> = {
       comparator: (a: E, b: E) => {
         if (!(typeof a === 'number' && typeof b === 'number')) {
           throw new Error('The a, b params of compare function must be number');
@@ -19,8 +20,7 @@ export class MaxHeap<E = any> extends Heap<E> {
           return b - a;
         }
       }
-    }
-  ) {
-    super(options);
+    }) {
+    super(elements, options);
   }
 }
diff --git a/src/data-structures/heap/min-heap.ts b/src/data-structures/heap/min-heap.ts
index e5181dd..65ef234 100644
--- a/src/data-structures/heap/min-heap.ts
+++ b/src/data-structures/heap/min-heap.ts
@@ -7,11 +7,12 @@
  */
 
 import { Heap } from './heap';
-import type { Comparator } from '../../types';
+import type { HeapOptions } from '../../types';
 
 export class MinHeap<E = any> extends Heap<E> {
   constructor(
-    options: { comparator: Comparator<E>; nodes?: E[] } = {
+    elements?: Iterable<E>,
+    options: HeapOptions<E> = {
       comparator: (a: E, b: E) => {
         if (!(typeof a === 'number' && typeof b === 'number')) {
           throw new Error('The a, b params of compare function must be number');
@@ -19,8 +20,7 @@ export class MinHeap<E = any> extends Heap<E> {
           return a - b;
         }
       }
-    }
-  ) {
-    super(options);
+    }) {
+    super(elements, options);
   }
 }
diff --git a/src/data-structures/linked-list/doubly-linked-list.ts b/src/data-structures/linked-list/doubly-linked-list.ts
index d7b9b90..dcb2da5 100644
--- a/src/data-structures/linked-list/doubly-linked-list.ts
+++ b/src/data-structures/linked-list/doubly-linked-list.ts
@@ -26,10 +26,15 @@ export class DoublyLinkedList<E = any> {
   /**
    * The constructor initializes the linked list with an empty head, tail, and length.
    */
-  constructor() {
+  constructor(elements?: Iterable<E>) {
     this._head = null;
     this._tail = null;
     this._length = 0;
+    if (elements) {
+      for (const el of elements) {
+        this.push(el);
+      }
+    }
   }
 
   protected _head: DoublyLinkedListNode<E> | null;
@@ -834,4 +839,8 @@ export class DoublyLinkedList<E = any> {
 
     return accumulator;
   }
+
+  print(): void {
+    console.log([...this]);
+  }
 }
diff --git a/src/data-structures/linked-list/singly-linked-list.ts b/src/data-structures/linked-list/singly-linked-list.ts
index d7372f0..d1d9a1a 100644
--- a/src/data-structures/linked-list/singly-linked-list.ts
+++ b/src/data-structures/linked-list/singly-linked-list.ts
@@ -24,10 +24,14 @@ export class SinglyLinkedList<E = any> {
   /**
    * The constructor initializes the linked list with an empty head, tail, and length.
    */
-  constructor() {
+  constructor(elements?: Iterable<E>) {
     this._head = null;
     this._tail = null;
     this._length = 0;
+    if (elements) {
+      for (const el of elements)
+        this.push(el);
+    }
   }
 
   protected _head: SinglyLinkedListNode<E> | null;
@@ -781,4 +785,8 @@ export class SinglyLinkedList<E = any> {
 
     return accumulator;
   }
+
+  print(): void {
+    console.log([...this]);
+  }
 }
diff --git a/src/data-structures/priority-queue/max-priority-queue.ts b/src/data-structures/priority-queue/max-priority-queue.ts
index f1765a9..5bfa218 100644
--- a/src/data-structures/priority-queue/max-priority-queue.ts
+++ b/src/data-structures/priority-queue/max-priority-queue.ts
@@ -6,11 +6,12 @@
  * @license MIT License
  */
 import { PriorityQueue } from './priority-queue';
-import type { Comparator } from '../../types';
+import type { PriorityQueueOptions } from '../../types';
 
 export class MaxPriorityQueue<E = any> extends PriorityQueue<E> {
   constructor(
-    options: { comparator: Comparator<E>; nodes?: E[] } = {
+    elements?: Iterable<E>,
+    options: PriorityQueueOptions<E> = {
       comparator: (a: E, b: E) => {
         if (!(typeof a === 'number' && typeof b === 'number')) {
           throw new Error('The a, b params of compare function must be number');
@@ -20,6 +21,6 @@ export class MaxPriorityQueue<E = any> extends PriorityQueue<E> {
       }
     }
   ) {
-    super(options);
+    super(elements, options);
   }
 }
diff --git a/src/data-structures/priority-queue/min-priority-queue.ts b/src/data-structures/priority-queue/min-priority-queue.ts
index 04276ee..a06b8ee 100644
--- a/src/data-structures/priority-queue/min-priority-queue.ts
+++ b/src/data-structures/priority-queue/min-priority-queue.ts
@@ -6,20 +6,20 @@
  * @license MIT License
  */
 import { PriorityQueue } from './priority-queue';
-import type { Comparator } from '../../types';
+import type { PriorityQueueOptions } from '../../types';
 
 export class MinPriorityQueue<E = any> extends PriorityQueue<E> {
-  constructor(
-    options: { comparator: Comparator<E>; nodes?: E[] } = {
-      comparator: (a: E, b: E) => {
-        if (!(typeof a === 'number' && typeof b === 'number')) {
-          throw new Error('The a, b params of compare function must be number');
-        } else {
-          return a - b;
-        }
-      }
-    }
+  constructor(elements?: Iterable<E>,
+              options: PriorityQueueOptions<E> = {
+                comparator: (a: E, b: E) => {
+                  if (!(typeof a === 'number' && typeof b === 'number')) {
+                    throw new Error('The a, b params of compare function must be number');
+                  } else {
+                    return a - b;
+                  }
+                }
+              }
   ) {
-    super(options);
+    super(elements, options);
   }
 }
diff --git a/src/data-structures/priority-queue/priority-queue.ts b/src/data-structures/priority-queue/priority-queue.ts
index e28121a..6978221 100644
--- a/src/data-structures/priority-queue/priority-queue.ts
+++ b/src/data-structures/priority-queue/priority-queue.ts
@@ -7,10 +7,10 @@
  */
 
 import { Heap } from '../heap';
-import { Comparator } from '../../types';
+import { PriorityQueueOptions } from '../../types';
 
 export class PriorityQueue<E = any> extends Heap<E> {
-  constructor(options: { comparator: Comparator<E>; nodes?: E[] }) {
-    super(options);
+  constructor(elements?: Iterable<E>, options?: PriorityQueueOptions<E>) {
+    super(elements, options);
   }
 }
diff --git a/src/data-structures/queue/deque.ts b/src/data-structures/queue/deque.ts
index 5ec2c2e..9326682 100644
--- a/src/data-structures/queue/deque.ts
+++ b/src/data-structures/queue/deque.ts
@@ -819,6 +819,10 @@ export class Deque<E> {
     return accumulator;
   }
 
+  print(): void {
+    console.log([...this])
+  }
+
   /**
    * Time Complexity: O(n)
    * Space Complexity: O(n)
diff --git a/src/data-structures/queue/queue.ts b/src/data-structures/queue/queue.ts
index 74b0302..32a7bab 100644
--- a/src/data-structures/queue/queue.ts
+++ b/src/data-structures/queue/queue.ts
@@ -300,6 +300,10 @@ export class Queue<E = any> {
     return new Queue(this.nodes.slice(this.offset));
   }
 
+  print(): void {
+    console.log([...this]);
+  }
+
   * [Symbol.iterator]() {
     for (const item of this.nodes) {
       yield item;
diff --git a/src/data-structures/stack/stack.ts b/src/data-structures/stack/stack.ts
index bfc4464..93cb0d3 100644
--- a/src/data-structures/stack/stack.ts
+++ b/src/data-structures/stack/stack.ts
@@ -10,8 +10,13 @@ export class Stack<E = any> {
    * of elements of type `E`. It is used to initialize the `_elements` property of the class. If the `elements` parameter
    * is provided and is an array, it is assigned to the `_elements
    */
-  constructor(elements?: E[]) {
-    this._elements = Array.isArray(elements) ? elements : [];
+  constructor(elements?: Iterable<E>) {
+    this._elements = [];
+    if (elements) {
+      for (const el of elements) {
+        this.push(el);
+      }
+    }
   }
 
   protected _elements: E[];
@@ -153,7 +158,7 @@ export class Stack<E = any> {
    * @returns An iterator object.
    */
   * [Symbol.iterator]() {
-    for (let i = this.elements.length - 1; i >= 0; i--) {
+    for (let i = 0; i < this.elements.length; i++) {
       yield this.elements[i];
     }
   }
@@ -203,4 +208,8 @@ export class Stack<E = any> {
     }
     return accumulator;
   }
+
+  print(): void {
+    console.log([...this]);
+  }
 }
diff --git a/src/types/data-structures/heap/heap.ts b/src/types/data-structures/heap/heap.ts
index cb0ff5c..ed8deed 100644
--- a/src/types/data-structures/heap/heap.ts
+++ b/src/types/data-structures/heap/heap.ts
@@ -1 +1,3 @@
-export {};
+import { Comparator } from "../../common";
+
+export type HeapOptions<T> = { comparator: Comparator<T> }
\ No newline at end of file
diff --git a/src/types/data-structures/priority-queue/priority-queue.ts b/src/types/data-structures/priority-queue/priority-queue.ts
index cb0ff5c..524b762 100644
--- a/src/types/data-structures/priority-queue/priority-queue.ts
+++ b/src/types/data-structures/priority-queue/priority-queue.ts
@@ -1 +1,3 @@
-export {};
+import { HeapOptions } from "../heap";
+
+export type PriorityQueueOptions<T> = HeapOptions<T> & {}
\ No newline at end of file
diff --git a/test/integration/conversion.test.ts b/test/integration/conversion.test.ts
deleted file mode 100644
index e69de29..0000000
diff --git a/test/unit/data-structures/heap/heap.test.ts b/test/unit/data-structures/heap/heap.test.ts
index d5f0499..84d4b7d 100644
--- a/test/unit/data-structures/heap/heap.test.ts
+++ b/test/unit/data-structures/heap/heap.test.ts
@@ -23,7 +23,7 @@ describe('Heap Operation Test', () => {
   });
 
   it('should object heap work well', function () {
-    const minHeap = new MinHeap<{ a: string; key: number }>({ comparator: (a, b) => a.key - b.key });
+    const minHeap = new MinHeap<{ a: string; key: number }>([], { comparator: (a, b) => a.key - b.key });
     minHeap.add({ key: 1, a: 'a1' });
     minHeap.add({ key: 6, a: 'a6' });
     minHeap.add({ key: 2, a: 'a2' });
@@ -43,7 +43,7 @@ describe('Heap Operation Test', () => {
       i++;
     }
 
-    const maxHeap = new MaxHeap<{ key: number; a: string }>({ comparator: (a, b) => b.key - a.key });
+    const maxHeap = new MaxHeap<{ key: number; a: string }>([], { comparator: (a, b) => b.key - a.key });
     maxHeap.add({ key: 1, a: 'a1' });
     maxHeap.add({ key: 6, a: 'a6' });
     maxHeap.add({ key: 5, a: 'a5' });
diff --git a/test/unit/data-structures/heap/max-heap.test.ts b/test/unit/data-structures/heap/max-heap.test.ts
index e665cf3..c8dc654 100644
--- a/test/unit/data-structures/heap/max-heap.test.ts
+++ b/test/unit/data-structures/heap/max-heap.test.ts
@@ -5,7 +5,7 @@ describe('MaxHeap', () => {
   let maxHeap: MaxHeap<number>;
 
   beforeEach(() => {
-    maxHeap = new MaxHeap({ comparator: numberComparator });
+    maxHeap = new MaxHeap([], { comparator: numberComparator });
   });
 
   it('add and poll elements in descending order', () => {
diff --git a/test/unit/data-structures/heap/min-heap.test.ts b/test/unit/data-structures/heap/min-heap.test.ts
index cdd8960..92f82df 100644
--- a/test/unit/data-structures/heap/min-heap.test.ts
+++ b/test/unit/data-structures/heap/min-heap.test.ts
@@ -5,7 +5,7 @@ describe('MinHeap', () => {
   let minHeap: MinHeap<number>;
 
   beforeEach(() => {
-    minHeap = new MinHeap({ comparator: numberComparator });
+    minHeap = new MinHeap([], { comparator: numberComparator });
   });
 
   it('add and poll elements in ascending order', () => {
diff --git a/test/unit/data-structures/priority-queue/max-priority-queue.test.ts b/test/unit/data-structures/priority-queue/max-priority-queue.test.ts
index 9e5f7ec..2461256 100644
--- a/test/unit/data-structures/priority-queue/max-priority-queue.test.ts
+++ b/test/unit/data-structures/priority-queue/max-priority-queue.test.ts
@@ -16,7 +16,7 @@ describe('MaxPriorityQueue Operation Test', () => {
   });
 
   it('should add elements and maintain heap property in a object MaxPriorityQueue', () => {
-    const priorityQueue = new MaxPriorityQueue<{ keyA: number }>({ comparator: (a, b) => b.keyA - a.keyA });
+    const priorityQueue = new MaxPriorityQueue<{ keyA: number }>([], { comparator: (a, b) => b.keyA - a.keyA });
     priorityQueue.refill([{ keyA: 5 }, { keyA: 3 }, { keyA: 1 }]);
     priorityQueue.add({ keyA: 7 });
 
@@ -52,7 +52,7 @@ describe('MaxPriorityQueue Operation Test', () => {
 
   it('should correctly heapify an array', () => {
     const array = [5, 3, 7, 1];
-    const heap = MaxPriorityQueue.heapify<number>({ elements: array, comparator: (a, b) => b - a });
+    const heap = MaxPriorityQueue.heapify<number>(array, { comparator: (a, b) => b - a });
     heap.refill(array);
 
     expect(heap.poll()).toBe(7);
@@ -63,7 +63,8 @@ describe('MaxPriorityQueue Operation Test', () => {
 
   it('should correctly heapify an object array', () => {
     const elements = [{ keyA: 5 }, { keyA: 3 }, { keyA: 7 }, { keyA: 1 }];
-    const maxPQ = MaxPriorityQueue.heapify<{ keyA: number }>({ elements, comparator: (a, b) => b.keyA - a.keyA });
+    debugger
+    const maxPQ = MaxPriorityQueue.heapify<{ keyA: number }>(elements, { comparator: (a, b) => b.keyA - a.keyA });
 
     expect(maxPQ.poll()?.keyA).toBe(7);
     expect(maxPQ.poll()?.keyA).toBe(5);
diff --git a/test/unit/data-structures/priority-queue/priority-queue.test.ts b/test/unit/data-structures/priority-queue/priority-queue.test.ts
index 1b9aed4..710bef5 100644
--- a/test/unit/data-structures/priority-queue/priority-queue.test.ts
+++ b/test/unit/data-structures/priority-queue/priority-queue.test.ts
@@ -5,7 +5,7 @@ import { isDebugTest } from '../../../config';
 const isDebug = isDebugTest;
 describe('PriorityQueue Operation Test', () => {
   it('should PriorityQueue poll, pee, heapify, toArray work well', function () {
-    const minPQ = new PriorityQueue<number>({ comparator: (a, b) => a - b });
+    const minPQ = new PriorityQueue<number>([], { comparator: (a, b) => a - b });
     minPQ.refill([5, 2, 3, 4, 6, 1]);
     expect(minPQ.toArray()).toEqual([1, 2, 3, 4, 6, 5]);
     minPQ.poll();
@@ -14,15 +14,14 @@ describe('PriorityQueue Operation Test', () => {
     expect(minPQ.toArray()).toEqual([4, 5, 6]);
     expect(minPQ.peek()).toBe(4);
     expect(
-      PriorityQueue.heapify({
-        elements: [3, 2, 1, 5, 6, 7, 8, 9, 10],
+      PriorityQueue.heapify([3, 2, 1, 5, 6, 7, 8, 9, 10], {
         comparator: (a, b) => a - b
       }).toArray()
-    ).toEqual([1, 2, 3, 5, 6, 7, 8, 9, 10]);
+    ).toEqual([1, 3, 2, 5, 6, 7, 8, 9, 10]);
   });
 
   it('should Max PriorityQueue poll, peek, heapify, toArray work well', function () {
-    const maxPriorityQueue = new PriorityQueue<number>({ comparator: (a, b) => b - a });
+    const maxPriorityQueue = new PriorityQueue<number>([], { comparator: (a, b) => b - a });
     maxPriorityQueue.refill([5, 2, 3, 4, 6, 1]);
     expect(maxPriorityQueue.toArray()).toEqual([6, 5, 3, 4, 2, 1]);
     maxPriorityQueue.poll();
@@ -31,15 +30,15 @@ describe('PriorityQueue Operation Test', () => {
     expect(maxPriorityQueue.toArray()).toEqual([3, 2, 1]);
     expect(maxPriorityQueue.peek()).toBe(3);
     expect(
-      PriorityQueue.heapify({
-        elements: [3, 2, 1, 5, 6, 7, 8, 9, 10],
+      PriorityQueue.heapify([3, 2, 1, 5, 6, 7, 8, 9, 10], {
+
         comparator: (a, b) => a - b
       }).toArray()
-    ).toEqual([1, 2, 3, 5, 6, 7, 8, 9, 10]);
+    ).toEqual([1, 3, 2, 5, 6, 7, 8, 9, 10]);
   });
 
   it('should PriorityQueue clone, sort, getNodes, dfs work well', function () {
-    const minPQ1 = new PriorityQueue<number>({ comparator: (a, b) => a - b });
+    const minPQ1 = new PriorityQueue<number>([], { comparator: (a, b) => a - b });
     minPQ1.refill([2, 5, 8, 3, 1, 6, 7, 4]);
     const clonedPriorityQueue = minPQ1.clone();
     expect(clonedPriorityQueue.elements).toEqual(minPQ1.elements);
@@ -52,7 +51,7 @@ describe('PriorityQueue Operation Test', () => {
 
 describe('Priority Queue Performance Test', () => {
   it('should numeric heap work well', function () {
-    const pq = new PriorityQueue({ comparator: (a, b) => b - a });
+    const pq = new PriorityQueue<number>([], { comparator: (a, b) => b - a });
 
     const tS = performance.now();
 
diff --git a/test/unit/data-structures/stack/stack.test.ts b/test/unit/data-structures/stack/stack.test.ts
index 8ee443d..15118d9 100644
--- a/test/unit/data-structures/stack/stack.test.ts
+++ b/test/unit/data-structures/stack/stack.test.ts
@@ -83,7 +83,7 @@ describe('Stack iterative methods', () => {
       result.push(element);
     }
 
-    expect(result).toEqual([3, 2, 1]); // iteration should start from the top of the stack
+    expect(result).toEqual([1, 2, 3]); // iteration should start from the top of the stack
   });
 
   test('should apply forEach to the stack', () => {
@@ -92,7 +92,7 @@ describe('Stack iterative methods', () => {
       result.push(element);
     });
 
-    expect(result).toEqual([3, 2, 1]);
+    expect(result).toEqual([1, 2, 3]);
   });
 
   test('should filter elements in the stack', () => {
diff --git a/test/unit/unrestricted-interconversion.test.ts b/test/unit/unrestricted-interconversion.test.ts
new file mode 100644
index 0000000..c970212
--- /dev/null
+++ b/test/unit/unrestricted-interconversion.test.ts
@@ -0,0 +1,59 @@
+import {
+  Deque,
+  DoublyLinkedList,
+  MaxHeap,
+  MaxPriorityQueue,
+  MinHeap,
+  MinPriorityQueue,
+  Queue,
+  SinglyLinkedList,
+  Stack
+} from '../../src';
+
+const orgArr: number[] = [6, 1, 2, 7, 5, 3, 4, 9, 8];
+describe('conversions', () => {
+  it('Array to Queue', () => {
+    const q = new Queue<number>(orgArr);
+    q.print();
+  })
+
+  it('Array to Deque', () => {
+    const dq = new Deque<number>(orgArr);
+    dq.print();
+  })
+
+  it('Array to SinglyLinkedList', () => {
+    const sl = new SinglyLinkedList<number>(orgArr);
+    sl.print();
+  })
+
+  it('Array to DoublyLinkedList', () => {
+    const dl = new DoublyLinkedList<number>(orgArr);
+    dl.print();
+  })
+
+  it('Array to Stack', () => {
+    const stack = new Stack<number>(orgArr);
+    stack.print();
+  })
+
+  it('Array to MinHeap', () => {
+    const minHeap = new MinHeap<number>(orgArr);
+    minHeap.print();
+  })
+
+  it('Array to MaxHeap', () => {
+    const maxHeap = new MaxHeap<number>(orgArr);
+    maxHeap.print();
+  })
+
+  it('Array to MinPriorityQueue', () => {
+    const minPQ = new MinPriorityQueue<number>(orgArr);
+    minPQ.print();
+  })
+
+  it('Array to MaxPriorityQueue', () => {
+    const maxPQ = new MaxPriorityQueue<number>(orgArr);
+    maxPQ.print();
+  })
+})
\ No newline at end of file