Merge pull request #211 from adityamep/add-heap-sort

Add Heap Sort implementation in Java

Author: Pradeepsingh61

Java/algorithms/sorting/HeapSort.java

@@ -0,0 +1,43 @@
+import java.util.Arrays;
+
+public class HeapSort {
+    static 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[left] > arr[largest])
+            largest = left;
+
+        if (right < n && arr[right] > arr[largest])
+            largest = right;
+
+        if (largest != i) {
+            int temp = arr[i];
+            arr[i] = arr[largest];
+            arr[largest] = temp;
+            heapify(arr, n, largest);
+        }
+    }
+
+    static void heapSort(int arr[]) {
+        int n = arr.length;
+
+        for (int i = n / 2 - 1; i >= 0; i--)
+            heapify(arr, n, i);
+
+        for (int i = n - 1; i >= 0; i--) {
+            int temp = arr[0];
+            arr[0] = arr[i];
+            arr[i] = temp;
+            heapify(arr, i, 0);
+        }
+    }
+
+    public static void main(String[] args) {
+        int arr[] = {12, 11, 13, 5, 6, 7};
+        System.out.println("Original array: " + Arrays.toString(arr));
+        heapSort(arr);
+        System.out.println("Sorted array: " + Arrays.toString(arr));
+    }
+}