Minor improvements

Author: rampatra

src/main/java/com/rampatra/common/MinHeap.java

@@ -3,8 +3,6 @@
 import java.util.Arrays;
 
 /**
- * Created by IntelliJ IDEA.
- * <p/>
  * A HEAP is a specialized tree-based ABSTRACT DATA TYPE that satisfies the heap property:
  * min-heap: All non-leaf elements are either smaller than or equal to their left and right child.
  * max-heap: All non-leaf elements are either greater than or equal to their left and right child.
@@ -16,17 +14,16 @@
  * Each successor can be found in O(log n). The algorithm in minHeapify() takes O(log n) time
  * Therefore, buildMinHeap() would take O(n log n) time BUT IF OBSERVED CAREFULLY IT TAKES 0(N) TIME.
  * <p/>
- * Used in the HeapSort algorithm. Also can be used to implement a PriorityQueue.
+ * Used in the HeapSort algorithm. Also can be used to implement a PriorityQueue. 
+ * <a href="@see http://staff.ustc.edu.cn/~csli/graduate/algorithms/book6/chap07.htm">Learn more</a>
  *
- * @author: ramswaroop
- * @date: 8/2/15
- * @time: 11:57 AM
- * @see: http://staff.ustc.edu.cn/~csli/graduate/algorithms/book6/chap07.htm
+ * @author rampatra
+ * @since 8/2/15
  */
 public class MinHeap {
 
-    int[] heap;
-    int size;
+    private int[] heap;
+    private int size;
 
     public MinHeap(int[] heap) {
         this.size = heap.length;
@@ -71,7 +68,7 @@ public void buildMinHeap() {
     }
 
     public void insert(int elem) {
-        heap = Arrays.copyOf(heap, size + 1);
+        heap = Arrays.copyOf(heap, 2 * size);
         int i = size;
         int parentIndex = (int) Math.floor((i - 1) / 2);
         while (i > 0 && elem < heap[parentIndex]) {
@@ -143,4 +140,4 @@ public static void main(String[] args) {
         minHeap.insert(0);
         minHeap.printHeap();
     }
-}
+}

src/main/java/com/rampatra/sorting/HeapSort.java

@@ -7,9 +7,8 @@
 /**
  * Created by IntelliJ IDEA.
  *
- * @author: ramswaroop
- * @date: 8/3/15
- * @time: 3:13 PM
+ * @author rampatra
+ * @since 8/3/15
  */
 public class HeapSort {
 
@@ -41,7 +40,7 @@ public static void heapSort(int[] a) {
      * @param index
      * @param end
      */
-    private static void maxHeapify(int[] a, int index, int end) {
+    public static void maxHeapify(int[] a, int index, int end) {
         int largest = index;
         int leftIndex = 2 * index + 1;
         int rightIndex = 2 * index + 2;
@@ -76,7 +75,7 @@ private static void swap(int[] a, int firstIndex, int secondIndex) {
         a[firstIndex] = a[firstIndex] - a[secondIndex];
     }
 
-    public static void main(String a[]) {
+    public static void main(String[] a) {
         int[] ar = new int[]{2, 5, 1, 7, 9, 4};
         System.out.println(Arrays.toString(ar));
         heapSort(ar);