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in reply to Re^2: Five Ways to Reverse a String of Words (C#, Perl 5, Perl6, Ruby, Haskell)
in thread Five Ways to Reverse a String of Words (C#, Perl 5, Perl 6, Ruby, Haskell)

How do you concatenate n strings in O(log n)? Every string will have to be concatenated to something least once, so it's not obvious to me how it could ever be less than O(n).

Concatenating in pairs and then concatenating the results etc adds up to O(n).