merge()

/* Merge the two sorted sub-arrays into a larger sorted (sub)array */
private static void merge(int[] elements, int[] aux, int low, int mid, int high) {

    for (int k = low; k <= high; k++) {             // 1
        aux[k] = elements[k];                       // 1
    }

    int i = low;                                    // 2
    int j = mid + 1;                                // 2
    for (int k = low; k <= high; k++) {             // 3
        if (i > mid) {                              // 4
            elements[k] = aux[j++];                 // 4
        } else if (j > high) {                      // 5
            elements[k] = aux[i++];                 // 5
        } else if (less(aux[j], aux[i])) {          // 6
            elements[k] = aux[j++];                 // 6
        } else {                                    // 7
            elements[k] = aux[i++];                 // 7
        }
    }
}