利用归并排序算法将读入的 n 个数从小到大排序后输出。JAVA

好的，下面是 Java 代码实现归并排序算法：

import java.util.Scanner;

public class MergeSort {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        int[] nums = new int[n];
        for (int i = 0; i < n; i++) {
            nums[i] = scanner.nextInt();
        }
        mergeSort(nums, 0, n - 1);
        for (int i = 0; i < n; i++) {
            System.out.print(nums[i] + " ");
        }
    }

    private static void mergeSort(int[] nums, int left, int right) {
        if (left < right) {
            int mid = (left + right) / 2;
            mergeSort(nums, left, mid);
            mergeSort(nums, mid + 1, right);
            merge(nums, left, mid, right);
        }
    }

    private static void merge(int[] nums, int left, int mid, int right) {
        int[] temp = new int[right - left + 1];
        int i = left, j = mid + 1, k = 0;
        while (i <= mid && j <= right) {
            if (nums[i] <= nums[j]) {
                temp[k++] = nums[i++];
            } else {
                temp[k++] = nums[j++];
            }
        }
        while (i <= mid) {
            temp[k++] = nums[i++];
        }
        while (j <= right) {
            temp[k++] = nums[j++];
        }
        for (int p = 0; p < temp.length; p++) {
            nums[left + p] = temp[p];
        }
    }
}

以上代码将读入的 n 个数存入数组 nums 中，然后调用 `mergeSort` 方法进行归并排序，最后输出排序后的结果即可。