Counterexample: List of Tuples: (1,1), (1,3),(3,1),(3,3),(2,2) with nX = nY = 2
(2,2) is within the "square" but needs to be removed -----Ursprüngliche Nachricht----- Von: sqlite-users [mailto:sqlite-users-boun...@mailinglists.sqlite.org] Im Auftrag von Barry Smith Gesendet: Mittwoch, 02. Mai 2018 00:12 An: SQLite mailing list <sqlite-users@mailinglists.sqlite.org> Betreff: [EXTERNAL] Re: [sqlite] probably recursive? Well those constraints simplify your problem. In the resultant dataset, the largest X and Y values will be equal, and the largest X will have and entry for every coordinate from (X, 1) to (X, X). Likewise the largest Y will have an entry for every coordinate from (1, Y) to (Y, Y). Basically you'll have two lines from the axes, drawing a square. All points outside that square will be culled, all points on and inside the square will be kept. Since you know that, you now have a one dimensional problem to solve. It still seems a little recursive to me, but it should be easier because you only need to find a single number (which you can then plug into a delete statement). If my statement about the square is not obvious to prove in your head I can try write a proof for that but I'm not much good at proofs. > On 2 May 2018, at 7:27 am, Roman Fleysher <roman.fleys...@einstein.yu.edu> > wrote: > > Pairs (x,y) do not repeat. > > Actual x and y are positive integers, but I do not see how being positive can > be relevant. Integer is important for sorting/comparison. > > > Roman > > ________________________________________ > From: sqlite-users [sqlite-users-boun...@mailinglists.sqlite.org] on behalf > of Barry Smith [smith.bar...@gmail.com] > Sent: Tuesday, May 01, 2018 5:23 PM > To: SQLite mailing list > Subject: Re: [sqlite] probably recursive? > > Is there a uniqueness constraint on your initial data? Can the same > coordinate be listed multiple times? > > Is there a requirement that X > 0 and Y > 0? > >>> On 2 May 2018, at 3:35 am, Simon Slavin <slav...@bigfraud.org> wrote: >>> >>> On 1 May 2018, at 6:28pm, Simon Slavin <slav...@bigfraud.org> wrote: >>> >>> I just realised that >> >> That was intended to be personal email. Apologies, everyone. >> >> Simon. >> _______________________________________________ >> sqlite-users mailing list >> sqlite-users@mailinglists.sqlite.org >> http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users > _______________________________________________ > sqlite-users mailing list > sqlite-users@mailinglists.sqlite.org > http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users > _______________________________________________ > sqlite-users mailing list > sqlite-users@mailinglists.sqlite.org > http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users ___________________________________________ Gunter Hick | Software Engineer | Scientific Games International GmbH | Klitschgasse 2-4, A-1130 Vienna | FN 157284 a, HG Wien, DVR: 0430013 | (O) +43 1 80100 - 0 May be privileged. May be confidential. Please delete if not the addressee. _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
