一、学习内容

        堆的结构可以分为大根堆和小根堆，是一个完全二叉树，而堆排序是根据堆的这种数据结构设计的一种排序。每个结点的值都大于其左孩子和右孩子结点的值，称之为大根堆；每个结点的值都小于其左孩子和右孩子结点的值，称之为小根堆。学习链接：堆排序算法（图解详细流程）_阿顾的博客-CSDN博客_堆排序

/**
	 *********************
	 * Heap sort. Maybe the most difficult sorting algorithm.
	 *********************
	 */
	public void heapSort() {
		DataNode tempNode;
		// Step 1. Construct the initial heap.
		for (int i = length / 2 - 1; i >= 0; i--) {
			adjustHeap(i, length);
		} // Of for i
		System.out.println("The initial heap: " + this + "\r\n");

		// Step 2. Swap and reconstruct.
		for (int i = length - 1; i > 0; i--) {
			tempNode = data[0];
			data[0] = data[i];
			data[i] = tempNode;

			adjustHeap(0, i);
			System.out.println("Round " + (length - i) + ": " + this);
		} // Of for i
	}// Of heapSort

	/**
	 *********************
	 * Adjust the heap.
	 * 
	 * @param paraStart  The start of the index.
	 * @param paraLength The length of the adjusted sequence.
	 *********************
	 */
	public void adjustHeap(int paraStart, int paraLength) {
		DataNode tempNode = data[paraStart];
		int tempParent = paraStart;
		int tempKey = data[paraStart].key;

		for (int tempChild = paraStart * 2 + 1; tempChild < paraLength; tempChild = tempChild * 2 + 1) {
			// The right child is bigger.
			if (tempChild + 1 < paraLength) {
				if (data[tempChild].key < data[tempChild + 1].key) {
					tempChild++;
				} // Of if
			} // Of if

			System.out.println("The parent position is " + tempParent + " and the child is " + tempChild);
			if (tempKey < data[tempChild].key) {
				// The child is bigger.
				data[tempParent] = data[tempChild];
				System.out.println("Move " + data[tempChild].key + " to position " + tempParent);
				tempParent = tempChild;
			} else {
				break;
			} // Of if
		} // Of for tempChild

		data[tempParent] = tempNode;

		System.out.println("Adjust " + paraStart + " to " + paraLength + ": " + this);
	}// Of adjustHeap

	/**
	 *********************
	 * Test the method.
	 *********************
	 */
	public static void heapSortTest() {
		int[] tempUnsortedKeys = { 5, 3, 6, 10, 7, 1, 9 };
		String[] tempContents = { "if", "then", "else", "switch", "case", "for", "while" };
		DataArray tempDataArray = new DataArray(tempUnsortedKeys, tempContents);

		System.out.println(tempDataArray);

		tempDataArray.heapSort();
		System.out.println("Result\r\n" + tempDataArray);
	}// Of heapSortTest

二、实现结果