Preliminary interview with one interviewer, approximately one hour.

First, the interviewer asked about a project I completed, followed by a coding question.

During the coding question, the interviewer added further complexities to the initial problem until it reached its final version, which I described.

Given a string that only contains lowercase letters, you need to delete repeated letters, leaving only one of each. The resulting string should be lexicographically as small as possible.

i.e. bcabc Delete the first 'b' and the first 'c'.