Phone Screen (45 min duration in total).

The interviewer said a little bit about himself and went straight to a technical question.

There were no background questions.

The interview process went as expected, with no surprises.

The interviewer seemed to be a nice guy.

Given a sequence of numbers (e.g., 34128) and an input map, such as a dial pad on a phone (2 -> [a, b, c], 3 -> [d, e, f], 4 -> [g, h, i]), write an algorithm to return all possible words from the sequence.

Example: Input: 232 Output: [ada, adb, adc, aea, aeb, aec, afa, afb, afc, bda, bdb, bdc, bea, beb, bec, bfa, bfb, bfc, cda, cdb, cdc, cea, ceb, cec, cfa, cfb, cfc]