Function insert

Data Structures/Treap persistent.cpp:66–70

  return t;
}
node* insert(node* t, int pos, int val) {
  node *l, *r;
  split(t, pos - 1, l, r);
  return merge(merge(l, new node(val)), r);
}
node* insert(node* t, int pos, node* x) {
  node *l, *r;
  split(t, pos - 1, l, r);