MergeSortMethods

public class MergeSortMethods {

    public static void divide(int[] arr, int l, int r) {
        if (l < r) {
            int m = (l + r) / 2;

            divide(arr, l, m);
            divide(arr, m + 1, r);

            SortMerge(arr, l, m, r);

        }
    }



        public static void SortMerge(int[] arr, int l, int m, int r) {
            int LeftHalf = m - l + 1;
            int RightHalf = r - l;

            int[] L = new int[LeftHalf];
            int[] R = new int[RightHalf];


            for (int i = 0; i < LeftHalf; i++) {
                L[i] = arr[l + i];
                i++;
            }

            for (int j = 0; j < RightHalf; j++) {
                R[j] = arr[m + 1 + j];
                j++;
            }


            int i = 0;
            int j = 0;

            int k = l;

            while (i < LeftHalf && j < RightHalf) {
                if (L[i] <= R[j]) {
                    arr[k] = L[i];
                    i++;
                } else {
                    arr[k] = R[j];
                    j++;
                }
                k++;
            }

            while (i < LeftHalf) {
                arr[k] = L[i];
                i++;
                k++;
            }

            while (j < RightHalf) {
                arr[k] = R[j];
                j++;
                k++;
            }
        }
}