堆排序

最新推荐文章于 2025-09-11 18:44:42 发布

转载最新推荐文章于 2025-09-11 18:44:42 发布 · 61 阅读

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原文链接：https://my.oschina.net/u/3342652/blog/1787965

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#数据结构与算法 #python

本文介绍了一种基于最大堆的堆排序算法实现。通过构建最大堆并进行调整来完成排序过程，详细展示了排序步骤及核心代码。

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public class HeapSort {

    private static int[] sort = new int[]{1, 0, 10, 20, 3, 5, 6, 4, 9, 8, 12,
            17, 34, 11};

    public static void main1() {
        buildMaxHeapify(sort);
        heapSort(sort);
        print(sort);
    }

    private static void buildMaxHeapify(int[] data) {
        int startIndex = getParentIndex(data.length - 1);
        for (int i = startIndex; i >= 0; i--) {
            maxHeapify(data, data.length, i);
        }
    }

    private static void maxHeapify(int[] data, int heapSize, int index) {
        int left = getChildLeftIndex(index);
        int right = getChildRightIndex(index);
        int largest = index;
        if (left < heapSize && data[index] < data[left]) {
            largest = left;
        }
        if (right < heapSize && data[largest] < data[right]) {
            largest = right;
        }
        if (largest != index) {
            int temp = data[index];
            data[index] = data[largest];
            data[largest] = temp;
            maxHeapify(data, heapSize, largest);
        }
    }

    /**
     * 排序，最大值放在末尾，data虽然是最大堆，在排序后就成了递增的
     *
     * @paramdata
     */
    private static void heapSort(int[] data) {
        for (int i = data.length - 1; i > 0; i--) {
            int temp = data[0];
            data[0] = data[i];
            data[i] = temp;
            maxHeapify(data, i, 0);
        }
    }

    /**
     * 父节点位置
     *
     * @return
     * @paramcurrent
     */
    private static int getParentIndex(int current) {
        return ;
    }

    /**
     * 左子节点position注意括号，加法优先级更高
     *
     * @return
     * @paramcurrent
     */
    private static int getChildLeftIndex(int current) {
        return (current << 1) + 1;
    }

    /**
     * 右子节点position
     *
     * @return
     * @paramcurrent
     */
    private static int getChildRightIndex(int current) {
        return (current << 1) + 2;
    }

    private static void print(int[] data) {
        int pre = -2;
        for (int i = 0; i < data.length; i++) {
            if (pre < (int) getLog(i + 1)) {
                pre = (int) getLog(i + 1);
                System.out.println();
            }
            System.out.print(data[i] + "|");
        }
    }

    /**
     * 以2为底的对数
     *
     * @return
     * @paramparam
     */
    private static double getLog(double param) {
        return Math.log(param) / Math.log(2);
    }
}