SIMD accelerated sorting in Java – how it works and why it was 3x faster(jbaker.io)

    int partition(int[] array, int from, int to, int pivot) {
        int[] buf1 = new int[to - from];
        int[] buf2 = new int[to - from]; // buffers could be preallocated, as in the blogpost

        int idx1 = 0;
        int idx2 = 0;

        for (int i = from; i < to; i++) {
            int value = array[i];
            if (value < pivot) {
                buf1[idx1++] = value;
            }
        }

        for (int i = from; i < to; i++) {
            int value = array[i];
            if (value >= pivot) {
                buf2[idx2++] = value;
            }
        }

        System.arraycopy(buf1, 0, array, from, idx1);
        System.arraycopy(buf2, 0, array, from, idx2);
    }