Algorithm to match one input file with given numbers of file

Question

I had an interview last week. I was stuck in one of the question in algorithm round. I answered that question, but the interviewer did not seem convinced. That\'s why I am s

Answer 1

diff them and pass through wc -l, or implement Levenshtein distance in C++ treating each line as a single character (or any more appropriate unit condidering the subject domain)