合并排序

所有子序列都进行两路合并，递归实现。

import java.util.Arrays;public class MergeSort {    public static int[] sort(int[] nums, int low, int high) {        int mid = (low + high) / 2;        if (low < high) {            // 左边            sort(nums, low, mid);            // 右边            sort(nums, mid + 1, high);            // 左右归并            merge(nums, low, mid, high);        }        return nums;    }    public static void merge(int[] nums, int low, int mid, int high) {        int[] temp = new int[high - low + 1];        int i = low;// 左指针        int j = mid + 1;// 右指针        int k = 0;        // 把较小的数先移到新数组中        while (i <= mid && j <= high) {            if (nums[i] < nums[j]) {                temp[k++] = nums[i++];            } else {                temp[k++] = nums[j++];            }        }        // 把左边剩余的数移入数组        while (i <= mid) {            temp[k++] = nums[i++];        }        // 把右边边剩余的数移入数组        while (j <= high) {            temp[k++] = nums[j++];        }        // 把新数组中的数覆盖部分nums数组        for (int k2 = 0; k2 < temp.length; k2++) {            nums[k2 + low] = temp[k2];        }    }    // 归并排序的实现    public static void main(String[] args) {        int[] nums = { 2, 7, 8, 3, 1, 6, 9, 0, 5, 4 };        MergeSort.sort(nums, 0, nums.length - 1);        System.out.println(Arrays.toString(nums));    }}