Note: this would fail if you had repeated numbers inside an item, like (1,1,2).

use strict;
my (@a, @b);

@a = (1,2,3);
@b = (5,6,7);
{
  my %test;
  @test{@a,@b}=1;
  print scalar keys %test == 6 ? 'ok' : 'not';
}
# ok

@a = (1,2,3);
@b = (2,4,6);
{
  my %test;
  @test{@a,@b}=1;
  print scalar keys %test == 6 ? 'ok' : 'not';
}
# not
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