java写的堆排序 代码

参照改写自  http://blog.kingsamchen.com/archives/547#viewSource

public class HeapSorter {

	int temp = 0;

	/*
	 * 输 入: Ary(int[]) - [in,out]排序数组 nIndex(int) - 起始下标 nHeapSize(int) - 堆大小 输
	 * 出: - 功 能: 从nIndex开始检查并保持最大堆性质
	 */
	void MaxHeapify(int Ary[], int nIndex, int nHeapSize) {
		while (true) {
			int nL = left(nIndex);
			int nR = right(nIndex);
			int nLargest;

			if (nL <= nHeapSize && Ary[nIndex] < Ary[nL]) {
				nLargest = nL;
			} else {
				nLargest = nIndex;
			}

			if (nR <= nHeapSize && Ary[nLargest] < Ary[nR]) {
				nLargest = nR;
			}

			if (nLargest != nIndex) {
				// 调整后可能仍然违反堆性质
				swap(Ary, nLargest, nIndex);
				nIndex = nLargest;
			} else {
				break;
			}
		}
	}

	/*
	 * 输 入: Ary(int[]) - [in,out]排序数组 nHeapSize(int) - [in]堆大小(zero-based) 输 出:
	 * - 功 能: 将一个数组改造为最大堆
	 */
	void BuildMaxHeap(int Ary[], int nHeapSize) {
		for (int i = parent(nHeapSize); i >= 0; --i) {
			MaxHeapify(Ary, i, nHeapSize);
		}
	}

	/*
	 * 输 入: Ary(int[]) - [in,out]排序数组 nCount(int) - [in]元素个数 输 出: - 功 能:
	 * 对一个数组进行堆排序
	 */
	void HeapSort(int Ary[], int nCount) {
		int nHeapSize = nCount - 1;

		BuildMaxHeap(Ary, nHeapSize);

		for (int i = nHeapSize; i >= 1; --i) {
			swap(Ary, 0, i);
			--nHeapSize;
			MaxHeapify(Ary, 0, nHeapSize);
		}
	}

	private void swap(int[] array, int index1, int index2) {
		temp = array[index1];
		array[index1] = array[index2];
		array[index2] = temp;
	}

	private int left(int x) {
		return (x << 1) + 1;
	}

	private int right(int x) {
		return (x + 1) << 1;
	}

	private int parent(int x) {
		return ((x + 1) >> 1) - 1;
	}

	public static void main(String[] s) {
		int a[] = {6, 16, 4, 10, 14, 7, 9, 3, 2, 8, 1 };
		new HeapSorter().HeapSort(a, 10);
		for (int i : a) {
			System.out.print(i + ",");
		}
	}
}

输出结果是:1,2,3,4,6,7,8,9,10,14,16,
未做优化.原文就不贴出了