Merge sort

package kr_2;

import java.util.*;

public class Mergesort {

    public static void merge(int[] arr, int[] l, int[] r, int left, int right) {
        int i = 0, j = 0, k = 0;
        while (i < left && j < right) {
            if (l[i] <= r[j]) {
                arr[k++] = l[i++];
            } else {
                arr[k++] = r[j++];
            }
        }
        while (i < left) {
            arr[k++] = l[i++];
        }
        while (j < right) {
            arr[k++] = r[j++];
        }

    }

    public static void mergeSort(int[] a, int n) {
        if (n < 2) {
            return;
        }
        int mid = n / 2;
        int[] l = new int[mid];
        int[] r = new int[n - mid];

        for (int i = 0; i < mid; i++) {
            l[i] = a[i];
        }
        for (int i = mid; i < n; i++) {
            r[i - mid] = a[i];
        }
        mergeSort(l, mid);
        mergeSort(r, n - mid);

        merge(a, l, r, mid, n - mid);
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.nextLine());
        Random rd = new Random();
        int[] arr = new int[n];
        for (int i = 0; i < arr.length; i++) {
            arr[i]=rd.nextInt();
        }
        mergeSort(arr, arr.length);
        for (int i = 0; i < arr.length; i++) {
            System.out.printf("Array[%d]=%d\n", i, arr[i]);
        }
    }

}