Create Max_Heap_Priority_Queue.java

Author: sksalahuddin2828

Diff for: Max_Heap_Priority_Queue.java

@@ -0,0 +1,82 @@
+import java.util.ArrayList;
+import java.util.List;
+
+class MaxHeap {
+    private List<Integer> heap;
+
+    public MaxHeap() {
+        heap = new ArrayList<>();
+    }
+
+    private void heapify(int n, int i) {
+        int largest = i;
+        int leftChild = 2 * i + 1;
+        int rightChild = 2 * i + 2;
+
+        if (leftChild < n && heap.get(i) < heap.get(leftChild)) {
+            largest = leftChild;
+        }
+
+        if (rightChild < n && heap.get(largest) < heap.get(rightChild)) {
+            largest = rightChild;
+        }
+
+        if (largest != i) {
+            int temp = heap.get(i);
+            heap.set(i, heap.get(largest));
+            heap.set(largest, temp);
+            heapify(n, largest);
+        }
+    }
+
+    public void insert(int newNum) {
+        int size = heap.size();
+        if (size == 0) {
+            heap.add(newNum);
+        } else {
+            heap.add(newNum);
+            for (int i = (size / 2) - 1; i >= 0; i--) {
+                heapify(size, i);
+            }
+        }
+    }
+
+    public void deleteNode(int num) {
+        int size = heap.size();
+        int i;
+        for (i = 0; i < size; i++) {
+            if (num == heap.get(i)) {
+                break;
+            }
+        }
+
+        int temp = heap.get(i);
+        heap.set(i, heap.get(size - 1));
+        heap.set(size - 1, temp);
+        heap.remove(size - 1);
+
+        for (i = (heap.size() / 2) - 1; i >= 0; i--) {
+            heapify(heap.size(), i);
+        }
+    }
+
+    public void printHeap() {
+        System.out.println("Max-Heap array: " + heap);
+    }
+}
+
+public class Main {
+    public static void main(String[] args) {
+        MaxHeap maxHeap = new MaxHeap();
+        maxHeap.insert(3);
+        maxHeap.insert(4);
+        maxHeap.insert(9);
+        maxHeap.insert(5);
+        maxHeap.insert(2);
+
+        maxHeap.printHeap();
+
+        maxHeap.deleteNode(4);
+        maxHeap.printHeap();
+    }
+}