归并排序

归并排序算法主要采用的是分治的思想，通过先分后治的方法来达到排序的目的。

具体代码如下：

private void mergeSort() {
        int[] nums = {11, 44, 23, 67, 88, 65, 34, 48, 9, 12};
        int[] temp = new int[nums.length];
        mergeSort(nums, 0, nums.length - 1, temp);
}

private void mergeSort(int[] nums, int low, int high, int[] temps) {
        if (low < high) {
            int mid = (low + high) / 2;
            mergeSort(nums, low, mid, temps);//先分左半部分
            mergeSort(nums, mid + 1, high, temps);//再分右半部分
            merge(nums, low, mid, high, temps);//再合并
            System.out.println(low + "/" + mid + "/" + high);
        } 
}

private void merge(int[] nums, int low, int mid, int high, int[] temps) {
        int i = 0;
        int j = low, k = mid + 1;
        while (j <= mid && k <= high) {
            if (nums[j] < nums[k]) {
                temps[i++] = nums[j++];
            } else {
                temps[i++] = nums[k++];
            }
        }

        while (j <= mid) {
            temps[i++] = nums[j++];
        }

        while (k <= high) {
            temps[i++] = nums[k++];
        }
        for (int l = 0; l < i; l++) {
            nums[low + l] = temps[l];
        }
}

对应归并排序更详细的分析可以看这篇文章https://www.cnblogs.com/chengxiao/p/6194356.html