Microsoft Software Engineer interview questions

The interviewer introduced himself and then asked me to tell him about myself. Then he asked me to find longest common prefix from an array of strings. We discussed an approach and then I had to code it down. he also asked me about the time complexity and then asked me to optimise it. I gave another approach and then he asked me to code it and give the time complexity. We optimised the solution further with a new approach and I coded it too. The interviewer was satisfied.