Consider the following test case:
["AGTAAAAA", "GGTAAAAA", "GATAAAAA", "GACAAAAA"]
The mutation is possible, but OJ returned -1.
Also the statement never says that you would have to have make the mutations through valid genes, which is the intent I guess. Also, I am not sure why the start mutation is not part of the bank, although it would not make much difference.
@amandeepgautam5 Sorry about the bug in my code, I will fix it soon.
I mean, sometimes you need to mutate multiple times to get the "end" gene string, which means that each mutation needs to be valid to make the whole mutations valid. But I will add this point to the desctiption.
Also, we assume that the starting point is already valid, so I did not add it to the bank.
Thank you for your suggestions!