Please, tell me what is the correct answer for test abcdeedcbaabcdeedcba?

Empty string

i think it will be
abcdeedcbaabcdeedcba ll give
---
abcddcbbcddcba


Edited by author 14.03.2009 20:54

I agree with  Vedernikoff Sergey (HSE: EconomicsForever!), it will be the empty string. Look at the sample in problem and you'll understand.

for :abcddcbbcddcba
the answer is ""