Group Shifted Strings

Given an array of strings (all lowercase letters), the task is to group them in such a way that all strings in a group are shifted versions of each other. Two string S and T are called shifted if,

S.length = T.length
and
S[i] = T[i] + K for
1 <= i <= S.length  for a constant integer K
For example strings {acd, dfg, wyz, yab, mop} are shifted versions of each other.

http://www.geeksforgeeks.org/group-shifted-string/