What I understood is author wanted **“Good Subsequence”** to be calculated and **not** Subsequence of an array.

After reading Problem statement again and again what I realise that goodsubsequence can only be derived from good sequence.

Good sequence=“She defines a good sequence of integers as a non-empty sequence such that the sum of the elements in each of its non-empty subsequences is divisible by m”.

In order to form a good sequence straight away remove elements from array not divisible by m.

For an array or String subsequence/Subset:-

(2^n-1). //-1 for removing null set

^ --> raise to

n–> No. of elements in array

Am I right?