bottom-up sort()

/* Bottom-up merge sort implementation */
public static void sort(int[] elements) {
    int[] aux = new int[elements.length];                                       // 1
    for (int size = 1; size < elements.length; size *= 2) {                     // 2
        for (int low = 0; low < elements.length - size; low += 2 * size) {      // 3
            int mid = low + size - 1;                                           // 4
            int high = Math.min(low + 2 * size - 1, elements.length - 1);       // 4
            merge(elements, aux, low, mid, high);                               // 5
        }
    }
}