In the best case and the average case scenario, an unordered_map is faster than a map because the best case and the average case time complexities of all the operations in an unordered_map (O(1)) are less than
core features, such as ordered and unordered lists, parent-child relationship, descendant elements and ancestors, HTML layouts. I also used some CSS core concepts, like cascading, inheritance and specificity, the CSS box model, the different selectors, combinators, classes and IDs, block and… ...
ComplexityA fifo_map object has the space overhead of:one std::unordered_map<Key, std::size_t> object to store the key order, one pointer to this object in the Compare object.Inserting a value (via operator[], insert) and removing a value (erase) rely on std::unordered_map::insert...