From be4bb44154c36a40af6a5852303dff68485a0051 Mon Sep 17 00:00:00 2001
From: Nitya <53599318+nitya123-github@users.noreply.github.com>
Date: Thu, 1 Oct 2020 07:03:13 +0530
Subject: [PATCH] heap sort

Heap sort is a comparison based sorting technique based on Binary Heap data structure. It is similar to selection sort where we first find the maximum element and place the maximum element at the end. We repeat the same process for the remaining elements.
---
 heap sort | 74 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 74 insertions(+)
 create mode 100644 heap sort

diff --git a/heap sort b/heap sort
new file mode 100644
index 0000000..629e6e2
--- /dev/null
+++ b/heap sort	
@@ -0,0 +1,74 @@
+// Java program for implementation of Heap Sort 
+public class HeapSort 
+{ 
+    public void sort(int arr[]) 
+    { 
+        int n = arr.length; 
+  
+        // Build heap (rearrange array) 
+        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 
+            int temp = arr[0]; 
+            arr[0] = arr[i]; 
+            arr[i] = temp; 
+  
+            // call max heapify on the reduced heap 
+            heapify(arr, i, 0); 
+        } 
+    } 
+  
+    // To heapify a subtree rooted with node i which is 
+    // an index in arr[]. n is size of heap 
+    void heapify(int arr[], int n, int i) 
+    { 
+        int largest = i; // Initialize largest as root 
+        int l = 2*i + 1; // left = 2*i + 1 
+        int r = 2*i + 2; // right = 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) 
+        { 
+            int swap = arr[i]; 
+            arr[i] = arr[largest]; 
+            arr[largest] = swap; 
+  
+            // Recursively heapify the affected sub-tree 
+            heapify(arr, n, largest); 
+        } 
+    } 
+  
+    /* A utility function to print array of size n */
+    static void printArray(int arr[]) 
+    { 
+        int n = arr.length; 
+        for (int i=0; i<n; ++i) 
+            System.out.print(arr[i]+" "); 
+        System.out.println(); 
+    } 
+  
+    // Driver program 
+    public static void main(String args[]) 
+    { 
+        int arr[] = {12, 11, 13, 5, 6, 7}; 
+        int n = arr.length; 
+  
+        HeapSort ob = new HeapSort(); 
+        ob.sort(arr); 
+  
+        System.out.println("Sorted array is"); 
+        printArray(arr); 
+    } 
+}