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<div dir="ltr" data-setdir="false">I realized I did not answer the question Doug posed, but the algorithm as originally presented works correctly and calculates correctly the number of possible knight pairings for each k x k board and generates the correct output requested by the problem.</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">The issue is still that, as I have implemented it in Haskell, it doesn't run fast enough to pass the automated CSES testing for n=10000. I am very curious whether it's possible to pass the speed testing for this problem using Haskell and if so how.</div><div><br></div>
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On Sunday, June 28, 2020, 09:49:02 AM PDT, Irfon-Kim Ahmad <irfon@ambienautica.com> wrote:
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<div class="ydp6b38afayiv2108629601moz-cite-prefix">On 2020-06-28 11:26 a.m., Doug McIlroy
wrote:<br clear="none">
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<pre class="ydp6b38afayiv2108629601moz-quote-pre">I'm currently stuck on the Two Knights problem.
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<pre class="ydp6b38afayiv2108629601moz-quote-pre">Having placed one knight on the board, in how many
places can you put the other?
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<p>If you check the website indicated, it's a slight variation on
that: <br clear="none">
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<p>"Your task is to count for <span class="ydp6b38afayiv2108629601MathJax_Preview" style="color:inherit;"></span><span class="ydp6b38afayiv2108629601MathJax" id="ydp6b38afayiv2108629601MathJax-Element-1-Frame" style="position:relative;"><span class="ydp6b38afayiv2108629601math" id="ydp6b38afayiv2108629601MathJax-Span-1" style="width:7.016em;display:inline-block;"><span style="display:inline-block;position:relative;width:6.14em;min-height:0px;font-size:114%;"><span><span class="ydp6b38afayiv2108629601mrow" id="ydp6b38afayiv2108629601MathJax-Span-2"><span class="ydp6b38afayiv2108629601mi" id="ydp6b38afayiv2108629601MathJax-Span-3" style="font-style:italic;">k</span><span class="ydp6b38afayiv2108629601mo" id="ydp6b38afayiv2108629601MathJax-Span-4" style="padding-left:0.278em;">=</span><span class="ydp6b38afayiv2108629601mn" id="ydp6b38afayiv2108629601MathJax-Span-5" style="padding-left:0.278em;">1</span><span class="ydp6b38afayiv2108629601mo" id="ydp6b38afayiv2108629601MathJax-Span-6">,</span><span class="ydp6b38afayiv2108629601mn" id="ydp6b38afayiv2108629601MathJax-Span-7" style="padding-left:0.167em;">2</span><span class="ydp6b38afayiv2108629601mo" id="ydp6b38afayiv2108629601MathJax-Span-8">,</span><span class="ydp6b38afayiv2108629601mo" id="ydp6b38afayiv2108629601MathJax-Span-9" style="padding-left:0.167em;">…</span><span class="ydp6b38afayiv2108629601mo" id="ydp6b38afayiv2108629601MathJax-Span-10" style="padding-left:0.167em;">,</span><span class="ydp6b38afayiv2108629601mi" id="ydp6b38afayiv2108629601MathJax-Span-11" style="font-style:italic;padding-left:0.167em;">n</span></span><span style="display:inline-block;width:0px;min-height:2.193em;"></span></span></span><span style="display: inline-block; vertical-align: -0.284em; border-left: 0px solid; width: 0px; min-height: 1.137em;"></span></span></span> the
number of ways two knights can be placed on a <span class="ydp6b38afayiv2108629601MathJax_Preview" style="color:inherit;"></span><span class="ydp6b38afayiv2108629601MathJax" id="ydp6b38afayiv2108629601MathJax-Element-2-Frame" style="position:relative;"><span class="ydp6b38afayiv2108629601math" id="ydp6b38afayiv2108629601MathJax-Span-12" style="width:2.578em;display:inline-block;"><span style="display:inline-block;position:relative;width:2.248em;min-height:0px;font-size:114%;"><span><span class="ydp6b38afayiv2108629601mrow" id="ydp6b38afayiv2108629601MathJax-Span-13"><span class="ydp6b38afayiv2108629601mi" id="ydp6b38afayiv2108629601MathJax-Span-14" style="font-style:italic;">k</span><span class="ydp6b38afayiv2108629601mo" id="ydp6b38afayiv2108629601MathJax-Span-15" style="padding-left:0.222em;">×</span><span class="ydp6b38afayiv2108629601mi" id="ydp6b38afayiv2108629601MathJax-Span-16" style="font-style:italic;padding-left:0.222em;">k</span></span><span style="display:inline-block;width:0px;min-height:2.193em;"></span></span></span><span style="display: inline-block; vertical-align: -0.075em; border-left: 0px solid; width: 0px; min-height: 0.929em;"></span></span></span>
chessboard so that they do not attack each other."<br clear="none">
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<p>The input is n (an integer that can range from 1 to 10000), the
output is a single integer for each value from 1 to n, one per
line, the memory limit is 512MB, and the maximum runtime is 1.00
seconds. </p><div class="ydp6b38afayiv2108629601yqt4596307336" id="ydp6b38afayiv2108629601yqtfd56774"><br clear="none">
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