here is the problem link : Anti Hash (SPOJ)

problem is related to polynomial string hashing , you are given P and M and also a string (let's say A) ,find and print another string (say B) which is different than A but have same hash as A.

here is what I am able to think till now : I am treating them as polynomial.

hash(A) = Polynomial Pa hash(B) = Polynomial Pb

since there hash is same hence , (Pa — Pb) % M must be zero.

I am not able to think how to proceed further.

any hint would be helpful , there are no editorial available for this problem.

Thank you.