hashing figure hash table after rehashing rehashing can be implemented in several ways with quadratic probing one alternative is to rehash as soon as the table is half full the other extreme is to rehash only when an insertion fails thirdmiddle-of-the-road strategy is to rehash when the table reaches certain load factor since performance does degrade as the load factor increasesthe third strategyimplemented with good cutoffcould be best rehashing for separate chaining hash tables is similar figure shows that rehashing is simple to implement and provides an implementation for separate chaining rehashing hash tables in the standard library in ++ the standard library includes hash table implementations of sets and maps-namelyunordered_set and unordered_mapwhich parallel set and map the items in the ordered_set (or the keys in the unordered_mapmust provide an overloaded operator=and hash functionas described earlierin section just as the set and map templates can