java实现冒泡排序,快速排序,希尔排序,堆排序算法

堆排序算法参考了下面的文章,在他的基础上改进了一点,原来有几个地方循环次数多了https://www.cnblogs.com/Java3y/p/8639937.html
public class TestThird {
    private static int[] ss = {334, 4, 532, 24, 147, 76, 735, 245, 734, 2356, 24, 334, 735};

    public static void main(String[] args) {
        int len = ss.length;
        for (int i = 0; i < len; i++) {
            System.out.print(" " + ss[i]);
        }
        System.out.println(" ");
//        heapSort(ss, len);
//        sort(0, len - 1);
//        bubbleSort(ss, len);
        shellSort(len);
        for (int i = 0; i < len; i++) {
            System.out.print(" " + ss[i]);
        }
    }

    //冒泡排序 思想是相邻两个数两两比较,经过一轮排序确认一个最大值,下轮循环就少循环一次
    private static void bubbleSort(int[] aa, int len) {
        for (int i = 0; i < len; i++) {
            for (int j = 1; j < len - i; j++) {
                if (aa[j] < aa[j - 1]) {
                    int temp = aa[j - 1];
                    aa[j - 1] = aa[j];
                    aa[j] = temp;
                }
            }
        }
    }

    //快速排序 思想找一个基准,通常选数组中的第一个元素,把比基准大的放在他的右边,比基准小的放在它的左边,
//最后基准的位置找到,这时,由基准的位置把数组分成了两部分,从新用上面方法,用到递归方法。
    private static void sort(int left, int right) {
        if (left >= right) {
            return;
        }
        int index = quickSort(left, right);
        sort(index + 1, right);
        sort(left, index - 1);
    }

    //快速排序的步骤
    private static int quickSort(int left, int right) {
        int key = ss[left];
        while (left < right) {
            while (left < right && ss[right] >= key) {
                right--;
            }
            ss[left] = ss[right];
            while (left < right && ss[left] <= key) {
                left++;
            }
            ss[right] = ss[left];

        }
        ss[left] = key;
        return left;
    }

    //堆排序 堆排序算法参考了下面的文章,在他的基础上改进了一点,原来有几个地方循环次数多了// https://www.cnblogs.com/Java3y/p/8639937.html
    private static void heapSort(int[] arr, int len) {
        madHeap(arr, len);
        int currentMaxIndex = len - 1;
        for (int i = 0; i < len; i++) {
            int temp = arr[0];
            arr[0] = arr[len - 1 - i];
            arr[len - 1 - i] = temp;
            heapAdjust(arr, 0, currentMaxIndex);
            currentMaxIndex--;
        }
    }

    //堆排序构建大根堆
    private static void madHeap(int[] arr, int size) {
        for (int i = (size - 1) / 2; i >= 0; i--) {
            heapAdjust(arr, i, size);
        }
    }

    //调整堆使之成为大根堆
    private static void heapAdjust(int[] arr, int index, int size) {
        int left = index * 2 + 1;
        int right = index * 2 + 2;
        int max = index;
        if (left < size) {
            if (arr[max] < arr[left]) {
                max = left;
            }
        }
        if (right < size) {
            if (arr[max] < arr[right]) {
                max = right;
            }
        }

        if (max != index) {
            int temp = arr[index];
            arr[index] = arr[max];
            arr[max] = temp;
            heapAdjust(arr, max, size);
        }
    }

    //希尔排序
    private static void shellSort(int len) {
        int temp = 0;
        int d = len;
        //下面的两个while循环 都是希尔排序的实现,只是想法不一样,插入的方式不同 第一个循环次数少
        while (true) {
            d = d / 2;
            for (int i = d; i < len; i++) {
                for (int j = i; j >= d; j = j - d) {
                    if (ss[j] < ss[j - d]) {
                        temp = ss[j];
                        ss[j] = ss[j - d];
                        ss[j - d] = temp;
                    }
                }

            }
            if (d == 1) {
                break;
            }
        }

        while (true) {
            d = d / 2;
            for (int i = 0; i < d; i++) {
                for (int j = i + d; j < len; j = j + d) {
                    for (int k = j - d; k >= 0; k = k - d) {
                        if (ss[k + d] < ss[k]) {
                            temp = ss[k];
                            ss[k] = ss[k + d];
                            ss[k + d] = temp;
                        }

                    }
                }

            }

            if (d == 1) {
                break;
            }
        }
    }


}
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转载自blog.csdn.net/u010502370/article/details/85121782