If you know the items are always sorted, there's a routine that's likely to be faster than anything else shown here as I post this:
my $ok = no_common_item_in_these_numeric_sorted_lists(
[1, 2, 3],
[2, 4, 6]
);
sub no_common_item_in_these_numeric_sorted_lists {
my @x = @{+shift}; # these are copies
my @y = @{+shift};
## presuming numeric sorted
while (@x or @y) {
shift @x, next if not @y or $x[0] < $y[0];
shift @y, next if not @x or $x[0] > $y[0];
return 0; # not ok - we found an identical item
}
return 1; # ok - we found no identical items
}
-- Randal L. Schwartz, Perl hacker
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