関連ワード:  delete from unordered_map c++    delete from unordered_map    delete from unordered map while iterating    unordered_map remove    remove from unordered_map c++    erase from unordered_map c++    unordered_map erase    delete element from unordered_map c++    delete key from unordered_map c++    delete entry from unordered_map c++