**Feb. 15, 2019** <br>

It is the algorithm in my phone screen from Microsoft in 2015. I just could not believe that it was a challenge algorithm for me at that time. I still remember that the discussion of this algorithm, and I was so surprised to learn so many things in phone interview.

**Nov. 1, 2023**<br>

I learned from the interviewer - Microsoft principle engineer showed me how to cut short and make one line statement to do checking.