Add PriorityQueue

Author: bcExpt1123

src/main/java/org/alda/Main.java

@@ -13,14 +13,16 @@
 import org.alda.structure.queue.Queue;
 import org.alda.structure.queue.array.QueueArray;
 import org.alda.structure.queue.linkedList.QueueLinkedList;
+import org.alda.structure.queue.priority.IPriorityQueue;
+import org.alda.structure.queue.priority.PriorityQueue;
 import org.alda.structure.stack.array.IStackArray;
 import org.alda.structure.stack.array.StackArray;
 import org.alda.structure.stack.linkedList.IStackLinkedList;
 import org.alda.structure.stack.linkedList.StackLinkedList;
 
 public class Main {
     public static void main(String[] args) {
-        testQueue();
+        testPriorityQueue();
     }
     public static void testSimpleLinkedList() {
         ISimpleLinkedList<Integer> intList = new SimpleLinkedList<Integer>();
@@ -183,4 +185,25 @@ public static void testQueueLinkedList(){
         System.out.println(front);
         System.out.println(rear);
     }
+
+    public static void testPriorityQueue(){
+        IPriorityQueue<Integer> intQueue = new PriorityQueue<>();
+
+        intQueue.enqueue(2, 1);
+        intQueue.enqueue(32, 25);
+        intQueue.enqueue(48, 0);
+        intQueue.enqueue(15, 3);
+        intQueue.enqueue(36, 2);
+        intQueue.enqueue(27, 4);
+
+        Integer item = intQueue.dequeue();
+        Integer item1 = intQueue.dequeue();
+        Integer item2 = intQueue.dequeue();
+        Integer item3 = intQueue.dequeue();
+
+        System.out.println(item);
+        System.out.println(item1);
+        System.out.println(item2);
+        System.out.println(item3);
+    }
 }

src/main/java/org/alda/structure/queue/priority/IPriorityQueue.java

@@ -0,0 +1,6 @@
+package org.alda.structure.queue.priority;
+
+public interface IPriorityQueue<T> {
+    void enqueue(T element, Integer priority);
+    T dequeue();
+}

src/main/java/org/alda/structure/queue/priority/Node.java

@@ -0,0 +1,12 @@
+package org.alda.structure.queue.priority;
+
+public class Node<T> {
+    public T data;
+    public Integer priority;
+    public Node<T> next;
+
+    public Node(T data, Integer priority){
+        this.data = data;
+        this.priority = priority;
+    }
+}

src/main/java/org/alda/structure/queue/priority/PriorityQueue.java

@@ -0,0 +1,36 @@
+package org.alda.structure.queue.priority;
+
+import org.alda.common.Comparer;
+
+public class PriorityQueue<T> implements IPriorityQueue<T> {
+    private Node<T> head;
+
+    public void enqueue(T data, Integer priority) {
+        Node<T> newNode = new Node<>(data, priority);
+        Node<T> current = null;
+        if(head == null) {
+            newNode.next = head;
+            head = newNode;
+        } else if (Comparer.compare(head.priority, newNode.priority) >= 0) {
+            newNode.next = head;
+            head = newNode;
+        } else {
+            current = head;
+            while (current.next != null && Comparer.compare(current.next.priority, newNode.priority) < 0) {
+                current = current.next;
+            }
+            newNode.next = current.next;
+            current.next = newNode;
+
+        }
+    }
+
+    public T dequeue() {
+        if(head == null) {
+            return null;
+        }
+        Node<T> current = head;
+        head = head.next;
+        return current.data;
+    }
+}