Method merge

Lecture 41 - Merge Sort/src/Main.java:7–28

(int[] arr, int l, int mid, int r)

        }
    }
    static void merge(int[] arr, int l, int mid, int r){
        int n1 = mid-l+1;
        int n2 = r-mid;
        int[] left = new int[n1];
        int[] right = new int[n2];
        int i, j, k;
        for(i = 0; i < n1; i++) left[i] = arr[l+i];
        for(j = 0; j < n2; j++) right[j] = arr[mid+1+j];
        i = 0;
        j = 0;
        k = l;
        while(i < n1 && j < n2){
            if(left[i] < right[j])
                arr[k++] = left[i++];
            else
                arr[k++] = right[j++];
        }
        while(i < n1)
            arr[k++] = left[i++];
        while (j < n2)
            arr[k++] = right[j++];
    }
    static void mergeSort(int[] arr, int l, int r){
        if(l >= r) return;
        int mid = (l+r)/2;