static int verify_dict_has_node(dnode_t *nil, dnode_t *root, dnode_t *node) { if (root != nil) { return root == node || verify_dict_has_node(nil, root->left, node) || verify_dict_has_node(nil, root->right, node); } return 0; }
int dict_contains(dict_t *dict, dnode_t *node) { return verify_dict_has_node(dict_nil(dict), dict_root(dict), node); }