常用排序算法之归并排序

常用排序算法之冒泡排序
常用排序算法之快速排序
常用排序算法之插入排序
常用排序算法之希尔排序
常用排序算法之选择排序
常用排序算法之堆排序
归并排序算法

/**     * 归并排序     * @param array     * @return     */    public static int[] mergingSort(int[] array) {        sort(array, 0, array.length - 1);        return array;    }    public static void sort(int[] data, int left, int right) {        if (left < right) {            //找出中间索引            int center = (left + right) / 2;            //对左边数组进行递归            sort(data, left, center);            //对右边数组进行递归            sort(data, center + 1, right);            merge(data, left, center, right);        }    }    public static void merge(int[] data, int left, int center, int right) {        int[] tmpArr = new int[data.length];        int mid = center + 1;        int third = left;        int tmp = left;        while (left <= center && mid <= right) {            if (data[left] <= data[mid]) {                tmpArr[third++] = data[left++];            } else {                tmpArr[third++] = data[mid++];            }        }        while (mid <= right) {            tmpArr[third++] = data[mid++];        }        while (left <= center) {            tmpArr[third++] = data[left++];        }        while (tmp <= right) {            data[tmp] = tmpArr[tmp++];        }    }

运行

/**     * 待排序的数组     */    private static int[] array = {            12, 10, 5, 9, 5, 32, 16, 1, 9, 99, 80, 3, 18, 19, 20, 25, 7, 15    };    public static void main(String[] args) {        int[] result = SortUtils.mergingSort(array.clone());        System.out.println(Arrays.toString(result));    }

输出

[1, 3, 5, 5, 7, 9, 9, 10, 12, 15, 16, 18, 19, 20, 25, 32, 80, 99]

常用算法时间复杂度和空间复杂度表