Priority queue js

[luckyb13]

Added Priority Queue Implementation (priorityQueue.js)

Overview
This PR introduces a reusable Priority Queue data structure implemented using a binary heap. It supports a custom comparator, enabling both min-heap and max-heap usage in real applications such as scheduling, graph algorithms (Dijkstra, A*), and task prioritization.

Key Features

• Binary heap implementation for efficient operations
• Custom comparator function support (default: min-heap)
• Public methods: push, pop, peek, size, isEmpty, clear
• Fully self-contained with no dependencies
• Node and browser compatible (ES Module)

Complexity

• push: O(log n)
• pop: O(log n)
• peek, size, isEmpty: O(1)
• Space: O(n)

Usage Example

import { PriorityQueue } from "./priorityQueue.js";

const pq = new PriorityQueue();
[5, 1, 4, 2, 3].forEach(x => pq.push(x));

while (!pq.isEmpty()) {
console.log(pq.pop()); // 1, 2, 3, 4, 5
}

Validation

• Verified ordering correctness with both small and large inputs
• Verified comparator customization for max-heap behavior
• Verified API behavior and error-free execution

Notes for Reviewers

• Clear function naming and private helper methods
• No existing functionality modified
• Code formatted consistently with repository style

Hacktoberfest Request
This is a meaningful contribution adding a widely-needed data structure. Please add the label:

hacktoberfest-accepted

Thank you.