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[RFC] libstdc++/19422: complexity of ass. containers range constr.
- From: Paolo Carlini <pcarlini at suse dot de>
- To: libstdc++ <libstdc++ at gcc dot gnu dot org>
- Cc: Matt Austern <austern at apple dot com>
- Date: Thu, 13 Jan 2005 18:51:18 +0100
- Subject: [RFC] libstdc++/19422: complexity of ass. containers range constr.
this interesting PR points out that we have a problem wrt the complexity
of range constructor (and range insert) when [i, j) is sorted: should be
linear, is n*log(n) instead, as in the generic case...
Indeed, internally, in the loop, insert_unique and insert_equal taking
ranges are using insert_unique/insert_equal taking a value, and
submitter seems definitely right.
Now, my immediate reaction: why we are not using instead the versions of
insert_unique/insert_equal that take an hint iterator too? That version
has guaranteed constant complexity if t is inserted right after p (Table
69) and that would be the case when [i, j) is already sorted, I think...
Is my reasoning correct? Comments?