Pardon me? That example would presumably return a sorting network or certain size and type; I'm not sure what you mean by "sort two networks". Memoization helps there because of recursive structure. I'll give another example that requires no explanation.

sub fibonacci {
  my $n = shift;
  return 0+($n==1) if $n < 2;

  state @mem;

  $mem[$n] //= fibonacci($n-1) + fibonacci($n-2);
}
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And before you ask: no, I do not foresee a need to produce two (different) Fibonacci sequences.