## String Expansion

You are given a string s consisting of lowercase alphabet characters, digits, and brackets"(" and ")". s encodes a longer string and is represented as concat...

You are given a string s consisting of lowercase alphabet characters, digits, and brackets"(" and ")". s encodes a longer string and is represented as concat...

Given a string of digits ip, generate all possible valid IP address combinations and return them in sorted order.

Given a string digits containing 2 to 9 inclusive, return in sorted lexicographic order all possible strings it could represent when mapping to letters on a ...

An upside down number is one that appears the same when flipped 180 degrees. Given n, return all upside down numbers as strings whose length is n, sorted in ...