The merge sort algorithm

Package com.ebiz.sort; 

Import java.util.Arrays; 

/ ** 
 * @author YHJ 
 * @Create 2019-09-03 22:21 
 * / ** 
 * merge sort (recursive) 
 * 
 * per phase sequence ①. o two numbers merge operation, a floor (n / 2) sequences 
 * ②. executed ① until each element has a 
* ③. compared between groups 
 * ④. repeat step ③ , until all elements sorted.
 * / 

Public  class the Merge { 


    public  static  void main (String [] args) { 

        int [] ARR = {8,4,5,7,1,3,6,2,9 }; 

      mergingSort (ARR); 

    } 


    public  static  int [] mergingSort ( int[] arr){
        if(arr.length <= 1){
            return arr;
        }

        int num = arr.length >> 1;
        int[] leftArr = Arrays.copyOfRange(arr, 0, num);
        int[] rightArr = Arrays.copyOfRange(arr, num, arr.length);
        System.out.println("split two array: " + Arrays.toString(leftArr) + " And " + Arrays.toString(rightArr));
        return mergeTwoArray(mergingSort(leftArr), mergingSort(rightArr));      //不断拆分为最小单元，再排序合并
    }

    private static int[] mergeTwoArray(int[] Of arr1, int [] arr2 is) {
         int I = 0, J = 0, K = 0 ;
         int [] = Result new new  int [arr1.length arr2.length +];   // apply extra storage space after the merger an array of 
        the while (I <arr1.length && J <arr2.length) {       // select a smaller value of the two sequences into a new array 
            IF (of arr1 [I] <= arr2 is [J]) { 
                Result [K ++ ] of arr1 = [I ++ ]; 
            } the else { 
                Result [K ++] = arr2 is [J ++ ]; 
            } 
        } 
        the while (I <arr1.length) {      // excess sequence of elements 1 into the new array
            Result [K ++] = of arr1 [I ++ ]; 
        } 
        the while (J <arr2.length) {      // sequence extra elements 2 into the new array 
            Result [K ++] = arr2 is [J ++ ]; 
        } 
        System.out.println ( "section Merging : "+ of Arrays.toString (Result));
         return Result; 
    } 



}