3 ms·

It isn’t. You are correct. This is useful to support the underlying hash function but at that point you might as well just improve that and take the power of tw

• vidarh 8y ago
  I think that boils down the problem nicely: if you're using a hash table or writing your own for a specialised use-case, you should pick a good hash function. But if you're writing a general purpose hashtable implementation you have to deal with the fact that a lot of users won't use a good hash while some will, so you need to find a tradeoff between using their hash as-is and mixing it up to improve on the bad ones. The latter need to come almost free, however, or you'll ruin performance for those who actually do their homework.