You are given a set S of n strings. Sum of length of all the strings <= 2 * 10^5. Now you have to find the size of the smallest generating set for these n strings. The smallest generating set is the minimal set that contains some arbitrary strings such that by concatenation some of its strings multiple times you can generate all the strings in the set S.
For example let the set S contains strings "eappl" , "apple" and "appleee" then the answer is 2 as you can have a set {"apple" , "e"} and using these strings you can generate all the other 3 strings. Also you can concatenate any string >= 0 times.
Link to the problem statement.