Practical numbers: Difference between revisions
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(No Paddy, you can't endlessly delete approaches which you wish to discourage. We are optimizing different things. Live and let live. Let others show their approach.) |
Thundergnat (talk | contribs) (→{{header|Raku}}: Do some smarter filtering. More verbose but MUCH faster for most numbers) |
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sub is-practical ($n) { |
sub is-practical ($n) { |
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return True if $n == 1; |
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| ⚫ | |||
return False if $n % 2; |
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my @proper = $n.&proper-divisors :sort; |
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return True if all( @proper.rotor(2 => -1).map: { .[0] / .[1] >= .5 } ); |
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| ⚫ | |||
+@proper-sums < $n-1 ?? False !! @proper-sums[^$n] eqv (^$n).list ?? True !! False |
+@proper-sums < $n-1 ?? False !! @proper-sums[^$n] eqv (^$n).list ?? True !! False |
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} |
} |
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given [ (1..333).hyper(:32batch).grep: { is-practical($_) } ]; |
given [ (1..333).hyper(:32batch).grep: { is-practical($_) } ]; |
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printf "%5s is practical? %s\n", $_, .&is-practical for 666, 6666, 66666;</lang> |
printf "%5s is practical? %s\n", $_, .&is-practical for 666, 6666, 66666, 672, 720;</lang> |
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{{out}} |
{{out}} |
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<pre>77 matching numbers: |
<pre>77 matching numbers: |
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666 is practical? True |
666 is practical? True |
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6666 is practical? True |
6666 is practical? True |
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66666 is practical? False |
66666 is practical? False |
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672 is practical? True |
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720 is practical? True</pre> |
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=={{header|Wren}}== |
=={{header|Wren}}== |
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