Working code:
#!/usr/bin/perl use warnings; use strict; use feature qw{ say }; use constant MAX => 20; use constant EMPTY => "\0" x ((MAX / 8) + 1); my @AoA = map [ map int rand 1 + MAX, 1 .. 4 ], 0 .. 1000; my @vectors = (EMPTY) x (MAX + 1); for my $num (0 .. MAX) { for my $pos (0 .. $#AoA) { vec($vectors[$num], $pos, 1) = grep($num == $_, @{ $AoA[$pos] +}) ? 1 : 0; } } print "@$_; " for @AoA; print "\n"; my $subarray = $AoA[0]; say "Selecting: @$subarray."; my $result = EMPTY; for my $num (@$subarray) { $result |= $vectors[$num]; } for my $i (0 .. $#AoA) { say "@{ $AoA[$i] }" unless vec($result, $i, 1); }

Update: Runs under 0.3s for 10_000 quadruples.

لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ

In reply to Re^2: Efficient selection mechanism? by choroba
in thread Efficient selection mechanism? by BrowserUk

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