std::unordered_multimap<Key,T,Hash,KeyEqual,Allocator>:: insert_range

Inserts a copy of each element in the range rg .

Each iterator in the range rg is dereferenced exactly once.

If any of the following conditions is satisfied, the behavior is undefined:

• value_type is not EmplaceConstructible into unordered_multimap from * ranges:: begin ( rg )
• rg and * this overlap.

If after the operation the new number of elements is greater than old max_load_factor() * bucket_count() a rehashing takes place.
If rehashing occurs (due to the insertion), all iterators are invalidated. Otherwise (no rehashing), iterators are not invalidated.

Parameters

Complexity

Average case \(\scriptsize N\) N , worst case \(\scriptsize O(N \cdot S + N)\) O(N·S+N) , where \(\scriptsize S\) S is size ( ) and \(\scriptsize N\) N is ranges:: distance ( rg ) .

Notes

Example

#include <iostream>
#include <unordered_map>
#include <utility>
void println(auto, const auto& container)
{
    for (const auto& [key, value] : container)
        std::cout << '{' << key << ',' << value << '}' << ' ';
    std::cout << '\n';
}
int main()
{
    auto container = std::unordered_multimap{std::pair{1, 11}, {3, 33}, {2, 22}, {4, 44}};
    const auto rg = {std::pair{-1, -11}, {3, -33}, {-2, -22}};
#ifdef __cpp_lib_containers_ranges
    container.insert_range(rg);
#else
    container.insert(rg.begin(), rg.end());
#endif
    println("{}", container);
}

{1,11} {-2,-22} {3,-33} {3,33} {2,22} {-1,-11} {4,44}

See also