heap problem added

Cpp/heapproblem.cpp

@@ -0,0 +1,87 @@
+// { Driver Code Starts
+// C++ program for implementation of Heap Sort
+#include <bits/stdc++.h>
+using namespace std;
+
+
+ // } Driver Code Ends
+// The functions should be written in a way that array become sorted 
+// in increasing order when heapSort() is called.
+
+class Solution
+{
+    public:
+    //Heapify function to maintain heap property.
+    void heapify(int arr[], int n, int i)  
+    {
+        int largest = i;
+
+int left =( 2 * i) +1;
+
+int right =( 2 * i) +2;
+
+if( left < n && arr [largest] < arr [ left ] )
+
+largest = left ;
+if( right < n && arr[ largest] < arr[ right ])
+
+ largest= right;
+
+if( largest != i)
+{
+swap (arr[i] , arr[largest]);
+heapify (arr , n , largest);
+}  
+     }
+   public:
+    //Function to build a Heap from array.
+    void buildHeap(int arr[], int n)  
+    { 
+
+      int pos = (n-1) / 2 ;
+for(int i = pos ; i>= 0 ; i-- ){
+heapify( arr , n , i ) ;
+ }
+    }
+   public:
+    //Function to sort an array using Heap Sort.
+    void heapSort(int arr[], int n)
+    {
+       buildHeap(arr,n);
+for (int i = n - 1; i > 0; i--) {
+swap(arr[0], arr[i]);
+heapify(arr, i, 0);
+}
+    }
+};
+
+
+
+
+
+// { Driver Code Starts.
+
+/* Function to print an array */
+void printArray(int arr[], int size)
+{
+    int i;
+    for (i=0; i < size; i++)
+        printf("%d ", arr[i]);
+    printf("\n");
+}
+
+// Driver program to test above functions
+int main()
+{
+    int arr[1000000],n,T,i;
+    scanf("%d",&T);
+    while(T--){
+    scanf("%d",&n);
+    for(i=0;i<n;i++)
+      scanf("%d",&arr[i]);
+    Solution ob;
+    ob.heapSort(arr, n);
+    printArray(arr, n);
+    }
+    return 0;
+}