Feature/varun/priority queue

data-structures-in-javascript/priority-queue.es6.js

@@ -0,0 +1,102 @@
+class Node {
+    constructor(data, priority) {
+        this.data = data;
+        this.priority = priority
+    }
+}
+
+/**
+ * Priority Queue Class here implements the data structure 'Priority Queue' using javascript array.
+ * Element with priority of smaller number are lined up 1st i.e. they are given higher priority.
+ * If for 2 elements they have same priority then in that case we serve it as FCFS i.e. new element is inserted
+ * at back of the already inserted element with same priority.
+ */
+class PriorityQueue {
+    constructor() {
+        this.queue = [];
+    }
+
+    /**
+     * @description It creates a new Node with (data and priority) and inserts it into queue based on priority.
+     * Priority with lowest number is at higher priority.
+     * @param {*} data Element which is to be inserted.
+     * @param {number} priority Priority of the element it be inserted.
+     */
+    insert(data, priority) {
+        // finding the position where to insert the data
+        let index = 0;
+        for (; index < this.size; index++) {
+            if (priority < this.queue[index].priority) {
+                break;
+            }
+        }
+        // creating new node and inserts data
+        let newNode = new Node(data, priority);
+        this.queue.splice(index, 0, newNode);
+    }
+
+    /**
+     * @description It removes the data of highest priority
+     */
+    remove() {
+        return this.queue.shift();
+    }
+
+    /**
+     * @description It returns the length of the queue
+     */
+    length() {
+        return this.queue.length;
+    }
+
+    /**
+     * @description It checks if the queue is empty
+     */
+    isEmpty() {
+        return this.queue.length === 0;
+    }
+
+    /**
+     * @description It iterates over the elements of queue
+     * @param {*} fn 
+     */
+    iterator(fn) {
+        for (let node of this.queue) {
+            fn(node);
+        }
+    }
+
+    /**
+     * @description It prints the queue
+     */
+    print() {
+        for (let node of this.queue) {
+            console.log('data:', node.data, 'priority:', node.priority);
+        }
+    }
+}
+
+
+
+
+
+let pQueue = new PriorityQueue();
+console.log(pQueue.isEmpty());
+pQueue.insert(12, 5);
+console.log(pQueue.isEmpty());
+pQueue.insert(55, 2);
+console.log(pQueue.length());
+pQueue.insert(23, 5);
+pQueue.insert(134, 8);
+pQueue.print();
+console.log(pQueue.remove());
+console.log(pQueue.length());
+console.log(pQueue.remove());
+console.log(pQueue.length());
+pQueue.insert(194, 11);
+pQueue.print();
+console.log(pQueue.iterator);
+
+pQueue.iterator(item => {
+    console.log(item);
+});

data-structures-in-javascript/priority-queue.js

@@ -0,0 +1,98 @@
+function Node(data, priority) {
+    this.data = data;
+    this.priority = priority
+}
+
+/**
+ * Priority Queue Class here implements the data structure 'Priority Queue' using javascript array.
+ * Element with priority of smaller number are lined up 1st i.e. they are given higher priority.
+ * If for 2 elements they have same priority then in that case we serve it as FCFS i.e. new element is inserted
+ * at back of the already inserted element with same priority.
+ */
+function PriorityQueue() {
+    this.queue = [];
+}
+
+/**
+ * @description It creates a new Node with (data and priority) and inserts it into queue based on priority.
+ * Priority with lowest number is at higher priority.
+ * @param {*} data Element which is to be inserted.
+ * @param {number} priority Priority of the element it be inserted.
+ */
+PriorityQueue.prototype.insert = function (data, priority) {
+    // finding the position where to insert the data
+    let index = 0;
+    for (; index < this.size; index++) {
+        if (priority < this.queue[index].priority) {
+            break;
+        }
+    }
+    // creating new node and inserts data
+    let newNode = new Node(data, priority);
+    this.queue.splice(index, 0, newNode);
+}
+
+/**
+ * @description It removes the data of highest priority
+ */
+PriorityQueue.prototype.remove = function () {
+    return this.queue.shift();
+}
+
+/**
+ * @description It returns the length of the queue
+ */
+PriorityQueue.prototype.length = function () {
+    return this.queue.length;
+}
+
+/**
+ * @description It checks if the queue is empty
+ */
+PriorityQueue.prototype.isEmpty = function () {
+    return this.queue.length === 0;
+}
+
+/**
+ * @description It iterates over the elements of queue
+ * @param {*} fn 
+ */
+PriorityQueue.prototype.iterator = function (fn) {
+    for (let node of this.queue) {
+        fn(node);
+    }
+}
+
+/**
+ * @description It prints the queue
+ */
+PriorityQueue.prototype.print = function () {
+    for (let node of this.queue) {
+        console.log('data:', node.data, 'priority:', node.priority);
+    }
+}
+
+
+
+
+
+let pQueue = new PriorityQueue();
+console.log(pQueue.isEmpty());
+pQueue.insert(12, 5);
+console.log(pQueue.isEmpty());
+pQueue.insert(55, 2);
+console.log(pQueue.length());
+pQueue.insert(23, 5);
+pQueue.insert(134, 8);
+pQueue.print();
+console.log(pQueue.remove());
+console.log(pQueue.length());
+console.log(pQueue.remove());
+console.log(pQueue.length());
+pQueue.insert(194, 11);
+pQueue.print();
+console.log(pQueue.iterator);
+
+pQueue.iterator(item => {
+    console.log(item);
+});