uint32_t arr_max(uint32_t *arr, size_t length)
{
  /* FIXME */

  size_t length_l= length/2;
  size_t length_r= length - length_l;

  uint32_t max_l= arr_max(&arr[0], length_l);
  uint32_t max_r= arr_max(&arr[length_l], length_r);

  if(max_l > max_r) {
    return(max_l);
  }
  else {
    return(max_r);
  }
}

void setup()
{
  Serial.begin(9600);
}

void loop()
{
  uint32_t arr[]= {
    1615, 1014, 2447, 3885, 3390, 1641, 3932, 3017,
    2465, 1823, 1790, 1188, 4046, 3214,  228, 2737,
       4, 3195, 1919, 1074, 3334, 3748, 2655,  572,
    2958, 3866, 1549, 1750,  576, 3973, 1963,  340,
    1056, 2819, 2777,  135, 3546, 1144, 2667,   22,
    2635,  409, 1143, 1715,  925,  909, 1030,  757,
       9, 3349, 3908, 2638, 3557, 3041, 1369, 1316,
    1570,  258, 1394, 3523, 2846, 1424, 3866,  621
  };

  Serial.print("arr_max(arr, 64)= ");
  Serial.println(arr_max(arr, 64));

  delay(5000);
}