Quantum::Superpositions doesn't sound like an appropriate module for efficiently comparing large arrays of strings, although in the future it might include some quantum XS code that will run very fast on a quantum CPU.

The easy way to extract unique items is to use a hash.

# for example
my %counts;

# count how many of each value you see.
$counts{$_}++ foreach (@array);

# Pull out only the ones you've seen exactly one of.
my @uniques = grep {$counts{$_} == 1} keys %counts;
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