practice #18
							
								
								
									
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							| @ -1,6 +1,7 @@ | ||||
| # Ignore Gradle project-specific cache directory | ||||
| .gradle | ||||
| 
 | ||||
| # Igonre the .idea directory | ||||
| .idea | ||||
| # Ignore Gradle build output directory | ||||
| build | ||||
| bin | ||||
| @ -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; | ||||
|     } | ||||
|  | ||||
| @ -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); | ||||
|         } | ||||
|     } | ||||
| } | ||||
|  | ||||
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