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Re: OT: CSES Number Spiral algorithm

From Tim Rentsch <tr.17687@z991.linuxsc.com>
Newsgroups comp.lang.c
Subject Re: OT: CSES Number Spiral algorithm
Date 2025-03-20 11:38 -0700
Organization A noiseless patient Spider
Message-ID <861puro8dh.fsf@linuxsc.com> (permalink)
References <vrhgqd$3ku1m$2@dont-email.me>

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DFS <nospam@dfs.com> writes:

> I don't have a C question, but rather I'd like input about algorithmic
> approaches.
>
> https://cses.fi/problemset/task/1071
>
> It's an 'infinite grid'.  You have to find the value at rows-columns
> from 1 to 10^9.
>
> First thing you notice about the 5x5 grid is the values in
> odd-numbered columns begin with the square of the column number, and
> the values in even-numbered rows begin with the square of the row
> number.
>
> I followed the number pattern and built a grid in Excel and expanded
> it to 10x10 for more testing.
>
> https://imgur.com/x4VymmA
>
> Then coded 4 conditions      solution
> 1. row <= col and col odd    (col * col) - row + 1
> 2. row <= col and col even   ((col-1) * (col-1)) + row
> 3. row >  col and row odd    ((row-1) * (row-1)) + col
> 4. row >  col and row even   (row * row) - col + 1
>
> My full C code submission was accepted the first time.
>
> How would you have done it?

This posting is not appropriate for comp.lang.c.  Putting "OT" in
the subject line doesn't excuse its lack of suitability.

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OT: CSES Number Spiral algorithm DFS <nospam@dfs.com> - 2025-03-20 12:47 -0400
  Re: OT: CSES Number Spiral algorithm Richard Heathfield <rjh@cpax.org.uk> - 2025-03-20 18:02 +0000
    Re: OT: CSES Number Spiral algorithm DFS <nospam@dfs.com> - 2025-03-23 12:30 -0400
      Re: OT: CSES Number Spiral algorithm Richard Heathfield <rjh@cpax.org.uk> - 2025-03-24 04:15 +0000
  Re: OT: CSES Number Spiral algorithm Kaz Kylheku <643-408-1753@kylheku.com> - 2025-03-20 18:32 +0000
    Re: OT: CSES Number Spiral algorithm DFS <nospam@dfs.com> - 2025-03-21 16:54 -0400
      Re: OT: CSES Number Spiral algorithm Kaz Kylheku <643-408-1753@kylheku.com> - 2025-03-22 01:55 +0000
  Re: OT: CSES Number Spiral algorithm Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-03-20 11:38 -0700
    Re: OT: CSES Number Spiral algorithm Richard Heathfield <rjh@cpax.org.uk> - 2025-03-20 20:07 +0000
      Re: OT: CSES Number Spiral algorithm Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-03-20 13:10 -0700
        Re: OT: CSES Number Spiral algorithm Richard Heathfield <rjh@cpax.org.uk> - 2025-03-21 03:40 +0000
          Re: OT: CSES Number Spiral algorithm Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-03-20 23:52 -0700
    Re: OT: CSES Number Spiral algorithm DFS <nospam@dfs.com> - 2025-03-20 16:54 -0400
      Re: OT: CSES Number Spiral algorithm Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-03-20 16:52 -0700
        Re: OT: CSES Number Spiral algorithm DFS <nospam@dfs.com> - 2025-03-20 20:26 -0400
          Re: OT: CSES Number Spiral algorithm Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-03-20 18:49 -0700
            Re: OT: CSES Number Spiral algorithm "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2025-03-21 14:18 -0700
        Re: OT: CSES Number Spiral algorithm DFS <nospam@dfs.com> - 2025-03-20 20:45 -0400

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