Shaun Jackman <sjackman@xxxxxxxx> writes: > unordered_set::erase returns an iterator to the next element in the hash > table. When the hash table is empty, this means checking every single > bucket. For a hash table that used to have a lot of elements (say one > million) which were all removed and now has only a few elements (say > two), erasing an element is very slow. I'm not using the iterator > returned by erase. Is there a way to avoid this situation? I'm not very > keen on checking the load_factor and resizing the number buckets. I think you have described the situation accurately. It would be easy for libstdc++ to expose a variant of erase which does not return an iterator (it's already there, but it's a private method), but that would be a non-standard extension to the standardized class. I recommend that you file an enhancement request at http://gcc.gnu.org/bugzilla/ to see what the libstdc++ maintainers think. Or you could try asking on the libstdc++@xxxxxxxxxxx mailing list. Ian
