I'm WA15 always.
My program passes all tests given there discussion, but can't AC.

Please help. Anyone knows about the test?

Edited by author 04.03.2014 21:46

Edited by author 05.03.2014 10:38

I had WA 29, these tests helped me:

abaaa
aab
Answer: aa

baaba
abb
Answer: aa

bcbbc
abcc
Answer: abb

Edited by author 18.10.2015 22:56

It is not clear from statement whether it is allowed to remove previously inserted  modifier from the string using operation 2: "Choose the position in the DNA sequence that contains a *letter*" while in operation 1: "Insert a *gene modifier* into any place of the DNA".
AC solution assumes that gene_modifier==letter, so answer for
a
zz
Is "a", not "azz"

abcba
bc
=> aba

abcbc
bc
=> abbbc

cba
ba
=> abcba

a
bbcc
=> a

a
bbccc
=> abbc

d
bbcc
=> bbccd

zzza
zzz
answer:
a

It test help me. It's not test 3. Good luck. =)