Category: C++

Use std::queue for FIFO processing.

Maintain a heap-ordered priority queue.

Store unique ordered keys in std::set.

Store ordered keys with duplicates in multiset.

Associate unique keys with values in an ordered map.

Map keys to multiple values with multimap.

Traverse containers with iterators and iterator categories.

Avoid name clashes with namespaces; prefer std:: qualified names.

Use #include and include guards; minimize macro magic.

Use STL containers, iterators, and algorithms as your default toolkit.