The question they asked me was an easier variation of expression add opertors leetcode question https://leetcode.com/problems/expression-add-operators/ . I was able to come with a solution and in the end he asked me if it could be improved. I suggested DP to cache all the states and he said this is what he was looking for. I am feeling good but at the same time a little uncertain becuase in the given time of 15 min I felt this question was a little tough and my code was messy.