It necessarily does. That is also the case where it might cause a rehash, however that’s less certain as many hashmaps will trade memory for storing the hashes to avoid recomputing them over and over. I’d assume they can use these hashes directly when reallocating, though they still need to perform collision resolution.

Either way properly sizing the hashmap is a good idea. Though load factor needs to be take in account, and I’m not sure whether the average hashmap multiplies the capacity by the maximum load factor in order to ensure there’s actually space for the number of items intended. I’d hope so, but…