ignoring return value of 'bool std::operator!=(const std::shared_ptr<_Tp>&, std::nullptr_t) [with _Tp = Bitmap; std::nullptr_t = std::nullptr_t]', declared with attribute nodiscard [-Wunused-result]

comparison of integer expressions of different signedness: 'std::vector<SearchNode>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]

unused variable 'found_parent' [-Wunused-variable]