added Heap Sort algorithm

C++/Sorting/Heap_Sort.cpp

@@ -0,0 +1,56 @@
+// C++ program for implementation of Heap Sort using vector
+#include <bits/stdc++.h>
+using namespace std;
+
+// Heapify method which create the max heap in O(n) cpmplexity
+void heapify(vector<int>& arr, int n, int i){
+    // Initialize largest as root
+    int largest = i;
+
+    // left index = 2*i + 1
+    int l = 2 * i + 1;
+
+    // right index = 2*i + 2
+    int r = 2 * i + 2;
+
+    // If left child is larger than root
+    if (l < n && arr[l] > arr[largest])
+        largest = l;
+
+    // If right child is larger than largest so far
+    if (r < n && arr[r] > arr[largest])
+        largest = r;
+
+    // If largest is not root
+    if (largest != i) {
+        swap(arr[i], arr[largest]);
+
+        heapify(arr, n, largest);
+    }
+}
+
+// Main function to do heap sort
+void heapSort(vector<int>& arr){
+    int n = arr.size();
+
+    for (int i = n / 2 - 1; i >= 0; i--)
+        heapify(arr, n, i);
+
+    // One by one extract an element from heap
+    for (int i = n - 1; i > 0; i--) {
+        // Move current root to end
+        swap(arr[0], arr[i]);
+
+        heapify(arr, i, 0);
+    }
+}
+
+int main(){
+    vector<int> arr = { 9, 4, 3, 8, 10, 2, 5 };
+
+    heapSort(arr);
+
+    cout << "Sorted array is: ";
+    for (int i = 0; i < arr.size(); ++i)
+        cout << arr[i] << " ";
+}