Erasing Elements

Use m.erase(key) to remove an entry by its key. The method returns the number of elements removed, which is 0 if the key wasn't found or 1 if the entry was deleted. You can also erase by iterator: m.erase(m.find(key)).

This is useful when you already have the iterator from a previous find operation and don't need to search again. Erasing a single element runs in $O(\log n)$ time. Use m.clear() to remove all entries at once, which is faster than erasing elements one by one in a loop.