Given a string containing only digits, restore it by returning all possible valid IP address combinations.
A valid IP address must be in the form of A.B.C.D, where A,B,C and D are numbers from 0-255. The numbers cannot be 0 prefixed unless they are 0.
return [“255.255.11.135”, “255.255.111.35”]. (Make sure the returned strings are sorted in order)