std::unordered_multimap<Key,T,Hash,KeyEqual,Allocator>::merge
template<class H2, class P2> void merge(std::unordered_map<Key, T, H2, P2, Allocator>& source); | (1) | (since C++17) |
template<class H2, class P2> void merge(std::unordered_map<Key, T, H2, P2, Allocator>&& source); | (2) | (since C++17) |
template<class H2, class P2> void merge(std::unordered_multimap<Key, T, H2, P2, Allocator>& source); | (3) | (since C++17) |
template<class H2, class P2> void merge(std::unordered_multimap<Key, T, H2, P2, Allocator>&& source); | (4) | (since C++17) |
Attempts to extract ("splice") each element in source and insert it into *this using the hash function and key equality predicate of *this.
No elements are copied or moved, only the internal pointers of the container nodes are repointed. All pointers and references to the transferred elements remain valid, but now refer into *this, not into source. Iterators referring to the transferred elements and all iterators referring to *this are invalidated.
The behavior is undefined if get_allocator() != source.get_allocator().
Parameters
| source | - | compatible container to transfer the nodes from |
Return value
(none).
Complexity
Average case O(N), worst case O(N*size()+N), where N is source.size().
Example
See also
|
(C++17) | extracts nodes from the container (public member function) |
| inserts elements or nodes (since C++17) (public member function) |
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