Function find

code/data-structures/cartesian_tree.cpp:23–28

    l->r = merge(l->r, r); augment(l); return l; }
  r->l = merge(l, r->l); augment(r); return r; }
node* find(node *t, int x) {
  while (t) {
    if (x < t->x) t = t->l;
    else if (t->x < x) t = t->r;
    else return t; }
  return NULL; }
node* insert(node *t, int x, int y) {
  if (find(t, x) != NULL) return t;
  pair<node*,node*> res = split(t, x);