// Return true if the subtree rooted at root
// contains value somewhere in it
bool contains(node* root,int value)
{
  if(root == nullptr)
    return false;
  if(root->data == value)
    return true;
  if(value < root->data)
    return contains(root->left,value);
  else
    return contains(root->right,value);
}

bool has_duplicates(node *root)
{
  if(root == nullptr)
    return false;
  if(contains(root->left,root->data))
    return true;
  if(contains(root->right,root->data))
    return true;
  return has_duplicates(root->left) || has_duplicates(root->right);
}