Adding heap sort to practice

.gitignore

@@ -1,6 +1,7 @@
 # Ignore Gradle project-specific cache directory
 .gradle
-
+# Igonre the .idea directory
+.idea
 # Ignore Gradle build output directory
 build
 bin

module8/src/main/java/com/hithomelabs/princeton1/module8/Heap.java

@@ -11,29 +11,13 @@ public class Heap{
 
     /*
     * * Sink Node T with to it's appropriate place in a Heap of size N, if it's children exist and are greater
+    * * Implement sink API to sink a node if it's sub-heap is not heap-order
     */
     public static <T> void sink(T[] arr, int root, int N){
-        // *  Check if at least one child exists
-        while(2 * root <= N){
-            int j = 2 * root;
-        // *  Check if the right child exists and is larger than the left child, if yes swap right and left child
-            if(j+1 <= N){
-                if (less(arr[j], arr[j+1])) j++;
-            }
-            if (!less(arr[root], arr[j])) break;
-            exch(arr, root, j);
-        // * The root node has now sunken low, call sink recursively with new node to check if it sinks further
-            root = j;
-        }
     }
 
     // * * Swim if element is not root, and parent is lesser than node
     public static <T extends Comparable<T>> void swim(T[] arr, int node, int N){
-        while(node > 1){
-            if(! less(arr[node/2],arr[node])) break;
-            exch(arr, node, node/2);
-            node = node/2;
-        }
     }
 
     private static <T> void exch(T[] arr, int i, int j){
@@ -43,7 +27,6 @@ public class Heap{
     }
 
     private static <T> boolean less(T v, T w){
-
         if(((Comparable<T>)v).compareTo(w) < 1 ) return true;
         else return false;
     }

module8/src/main/java/com/hithomelabs/princeton1/module8/HeapSort.java

@@ -10,22 +10,18 @@ public class HeapSort<E> extends AbstractCustomSorts<E> {
         int N = arr.length;
 
         E[] heapArr = (E[]) new Object[N+1];
-        // * * to simplify we copy original array from
+        // * * to simplify we copy original array and write it to the new array starting index 1
         System.arraycopy(arr, 0, heapArr, 1, N);
-
         // * * An array of size N holds a heap of size N-1
         coreSortingLogic(heapArr, N);
+        // * * Re-copying the sorted array to the original
         System.arraycopy(heapArr, 1, arr, 0, N);
     }
 
+    /*
+     * * Implement the core sorting logic
+     * * P.S the provision of making the index 0 null for ease of use has already been done above
+    */
     private void coreSortingLogic(E[] arr, int N) {
-        // * * Converting array to max-heap an array in place
-        for (int i = N/2; i >= 1; i--)
-            Heap.sink(arr, i, N);
-        // * * After converting to max-heap, in every iteration remove the max element of the heap
-        while(N > 1){
-            exch(arr, 1, N--);
-            Heap.sink(arr, 1, N);
-        }
     }
 }