题解 | #输入整型数组和排序标识，对其元素按照升序或降序进行排序#

import java.util.*;
public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int number = Integer.valueOf(scan.nextLine().trim());
        String line = scan.nextLine();
        String[] strs = line.split(" ");
        int[] nums = new int[strs.length];
        for (int i = 0; i < nums.length; i++) {
            nums[i] = Integer.valueOf(strs[i].trim());
        }
        int sign = Integer.valueOf(scan.nextLine().trim());
        mergeSort(nums, sign);
        for (int i = 0; i < nums.length; i++) {
            if (i == nums.length - 1) {
                System.out.print(nums[i]);
                return;
            }
            System.out.print(nums[i] + " ");
        }
    }
    public static void mergeSort(int[] nums, int sign) {
        if (null == nums || nums.length < 2) {
            return;
        }
        process(nums, 0, nums.length - 1, sign);
    }
    public static void process(int[] nums, int start, int end, int sign) {
        if (start >= end) {
            return;
        }
        int mid = start + ((end - start) >> 1);
        process(nums, start, mid, sign);
        process(nums, mid + 1, end, sign);
        if (sign == 0) {
            merge1(nums, start, mid, end);
        } else {
            merge2(nums, start, mid, end);
        }
    }
    public static void merge1(int[] nums, int start, int mid, int end) {
        int[] helper = new int[end - start + 1];
        int index = 0;
        int p1 = start;
        int p2 = mid + 1;
        while (p1 <= mid && p2 <= end) {
            helper[index++] = nums[p1] <= nums[p2] ? nums[p1++] : nums[p2++];
        }
        while (p1 <= mid) {
            helper[index++] = nums[p1++];
        }
        while (p2 <= end) {
            helper[index++] = nums[p2++];
        }
        for (int i = 0; i < helper.length; i++) {
            nums[start + i] = helper[i];
        }
    }
    public static void merge2(int[] nums, int start, int mid, int end) {
        int[] helper = new int[end - start + 1];
        int index = 0;
        int p1 = start;
        int p2 = mid + 1;
        while (p1 <= mid && p2 <= end) {
            helper[index++] = nums[p1] >= nums[p2] ? nums[p1++] : nums[p2++];
        }
        while (p1 <= mid) {
            helper[index++] = nums[p1++];
        }
        while (p2 <= end) {
            helper[index++] = nums[p2++];
        }
        for (int i = 0; i < helper.length; i++) {
            nums[start + i] = helper[i];
        }
    }
}