Phone interview:
The Interviewer was late for 20 mins... Ask nothing on my resume.
Tow questions:
1) A string consists of ‘0’, ‘1’ and '?'. The question mark can be either '0' or '1'. Find all possible combinations for a string.
2) Give you a text file, remove duplicated lines.
Follow up: If the file is very large, general hash map takes too much spaces, come up with a better solution.