cpp/container/map/emplace hint

Inserts a new element to the container as close as possible to the position just before. The element is constructed in-place, i.e. no copy or move operations are performed.

The constructor of the element type (, that is, ) is called with exactly the same arguments as supplied to the function, forwarded with.

Return value
Returns an iterator to the newly inserted element.

If the insertion failed because the element already exists, returns an iterator to the already existing element with the equivalent key.

Exceptions
If an exception is thrown by any operation, this function has no effect (strong exception guarantee).

Complexity
Logarithmic in the size of the container in general, but amortized constant if the new element is inserted just before.