Алгоритм Карацубы для умножения полиномов

struct Polynom {
  double koef;
  int step;
};
 
Polynom kara(Polynom* polyn1, int size1, Polynom* polyn2, int size2) {
  int n;
  if (polyn1[size1].step < polyn2[size2].step)
  n = polyn2[size2].step;
  else 
  n = polyn1[size1].step;
  if (n == 1) {
    // polyn1 = 1x + 1
    // polyn2 = 2x + 2
    // XY =   (1*2)x^2 + ((1+1)(2+2) - 2 - 2)T + (1*2) = 
    Polynom* buff_res = new Polynom[3];
    buff_res[2].koef = polyn1[1].koef*polyn2[1].koef;
    buff_res[0].koef = polyn1[0].koef*polyn2[0].koef;
    buff_res[1].koef = ((polyn1[0].koef+polyn1[1].koef)*(polyn2[0].koef + polyn2[1].koef) - buff_res[2].koef - buff_res[0].koef);
    return *buff_res;
  }
 
  int mid1 = size1/2, mid2 = size2/2;
  Polynom* buff1_l = new Polynom[mid1];
  Polynom* buff1_r = new Polynom[size1-mid1];
  Polynom* buff2_l = new Polynom[mid2];
  Polynom* buff2_r = new Polynom[size2-mid2];
  for (int i = 0; i < mid1; i++) {
    buff1_l[i].koef = polyn1[i].koef;
    buff1_l[i].step = polyn1[i].step;}
  for (int i = mid1+1; i < size1; i++) {
    buff1_r[i].koef = polyn1[i].koef;
    buff1_r[i].step = (polyn1[i].step - 2);}
  for (int i = 0; i < mid1; i++) {
    buff2_l[i].koef = polyn2[i].koef;
    buff2_l[i].step = polyn2[i].step;}
  for (int i = mid2 + 1; i < size2; i++) {
    buff2_r[i].koef = polyn2[i].koef;
    buff2_r[i].step = (polyn2[i].step - 2);}
 
  Polynom* res1 = new Polynom[];
  *res1 = kara(buff1_l, mid1, buff2_l, mid2);
  Polynom* res2 = new Polynom[];
  *res2 = kara(buff1_r, size1 - mid1, buff2_r, size2 - mid2);
  Polynom* res3 = new Polynom[];
  *res3 = kara(polyn1, size1, polyn2, size2);
  Polynom* res  = new Polynom[];
  /*?*/
  return /*?*/;
}