I have no idea what is the difference between this code and this code ?

Problem is here.

Thank in advance.

How can I find out whether the problem is a Special Judge Problem or NOT ? Do there are any common condition or specification for identifying this type of problem ? Thanks in advance.

Anyone here to help me please ? I have no idea about this "Discrete Logarithm" or "Shank's baby-step giant-step algorithm" . I have found this . But it is beyond my understanding. Is there anyone who can make it easy to me, please ?