sort2.c — see for example "Faster sorting algorithms discovered using deep reinforcement learning" — https://www.nature.com/articles/s41586-023-06004-9

sort2.c

void variable_sort_2(int length, int *a) {
  if(length == 2){
    if(a[0] > a[1]){
      int temp = a[0];
      a[0] = a[1];
      a[1] = temp;
    }
  }
}

static int a0[] = {};

int main(void){
  variable_sort_2(0, a0);
  return 0;
}