Given a string S and a string T, count the number of distinct subsequences ofT inS. A subsequence of a string is a new string which is formed from the original string by deleting some (can be none) of the characters without disturbing the relative po
Description We give the following inductive definition of a “regular brackets” sequence: the empty sequence is a regular brackets sequence, if s is a regular brackets sequence, then (s) and [s] are regular brackets sequences, and if a and b are regul