Print all distinct Subsets of a given Set

Given a set S, generate all distinct subsets of it i.e., find distinct power set of set S. A power set of any set S is the set of all subsets of S, including the empty set and S itself.  

Maximum Length Snake Sequence

Given a square matrix, print maximum length snake sequence in it. A Snake sequence is defined as a sequence of numbers where each new number, which can only be located to the right or down of the current number, is either plus or minus one.