String concatenation in Java is O(N), which together with the loop over the input makes your solution O(N^2).
Outputing the answer char by char right away in the loop would be one way to get around this. -- You received this message because you are subscribed to the Google Groups "Google Code Jam" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/google-code/178bc61f-34f3-4578-90ec-d87fd98a36fa%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
