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std::unordered_map::rehash(3) C++ Standard Libary std::unordered_map::rehash(3)


std::unordered_map::rehash - std::unordered_map::rehash


void rehash( size_type count ); (since C++11)

Sets the number of buckets to count and rehashes the container, i.e. puts the
elements into appropriate buckets considering that total number of buckets has
changed. If the new number of buckets makes load factor more than maximum load
factor (count < size() / max_load_factor()), then the new number of buckets is at
least size() / max_load_factor().


count - new number of buckets

Return value



Average case linear in the size of the container, worst case quadratic.


rehash(0) may be used to force an unconditional rehash, such as after suspension of
automatic rehashing by temporarily increasing max_load_factor().

See also

reserve reserves space for at least the specified number of elements and regenerates
(C++11) the hash table
(public member function)