Added custom Heap Sort algorithm for Hacktoberfest 2025

Author: chintansood

sorting/heap_sorting.cpp

@@ -0,0 +1,30 @@
+#include <iostream>
+using namespace std;
+
+void heapify(int arr[], int n, int i) {
+    int largest = i;
+    int l = 2*i + 1;
+    int r = 2*i + 2;
+    if (l < n && arr[l] > arr[largest]) largest = l;
+    if (r < n && arr[r] > arr[largest]) largest = r;
+    if (largest != i) {
+        swap(arr[i], arr[largest]);
+        heapify(arr, n, largest);
+    }
+}
+
+void heapSort(int arr[], int n) {
+    for (int i = n / 2 - 1; i >= 0; i--) heapify(arr, n, i);
+    for (int i = n - 1; i >= 0; i--) {
+        swap(arr[0], arr[i]);
+        heapify(arr, i, 0);
+    }
+}
+
+int main() {
+    int arr[] = {12, 11, 13, 5, 6, 7};
+    int n = sizeof(arr) / sizeof(arr[0]);
+    heapSort(arr, n);
+    cout << "Sorted array: ";
+    for (int i = 0; i < n; i++) cout << arr[i] << " ";
+}