On Tue, 11 Feb 2025 at 18:33, Александр Поваляев via Std-Proposals <
std-proposals_at_[hidden]> wrote:

> *[[[My comments in bold]]]*
>
> вт, 11 февр. 2025 г. в 21:06, Bo Persson via Std-Proposals <
> std-proposals_at_[hidden]>:
>
>> On tis 2025-02-11 at 09:29, Александр Поваляев via Std-Proposals wrote:
>> > A Proposal to Add a New Multiset container Method to the Standard
>> > Library Technical Report
>> >
>>
>> > C++ Containers library std::multiset
>> >
>> > (1) size_type reduce( const Key& key );
>> >
>> > (2)
>> > template< class K >
>> > size_type reduce( K&& x );
>> >
>> > (3) size_type reduce( const Key& key, size_type count );
>> >
>> > (4)
>> > template< class K >
>> > size_type reduce( K&& x, size_type count );
>> >
>> > This method acts in right the opposite way to how method 'insert' does.
>> > Method 'reduce' decreases the number of std::multiset elements with
>> > the same key value. And while being supplied within the second argument
>> > 'size_type count', method 'reduce' decreases the number of std::multiset
>> > elements with the same key value but several times.
>> >
>>
>> How do we know if the function is to remove the oldest or the newest
>> inserts? Or some in the middle?
>>
> *[[[Aleksandr]]] I believe it should be in the priority queue like style. *
>

No, there is no priority here.


> *https://en.cppreference.com/w/cpp/container/multiset
> <https://en.cppreference.com/w/cpp/container/multiset> says "*
>
> *The order of the elements that compare equivalent is the order of
> insertion and does not change.*
> *(since C++11)**", so the oldest inserts should be deleted.*
>

It doesn't say anything about "oldest". You cannot know which are the
"oldest", you can only know which are the closest to the beginning of the
container.

If you insert every equivalent element using a hint, you can put the newer
elements before the older ones, or after them. So the order of equivalent
elements is not in oldest to newest, or newest to oldest. It depends on how
they were inserted.