Easy-Mid problems

Bring a whiteboard or a laptop or a piece of paper. We will be solving 1 easy and 1 medium problem on LeetCode. We have no rules for being late or leaving early, you can be late and start from the second problem or do the first one and leave. The main idea is to work together on it, share thoughts and discuss a solution. For those who don't like the time pressure during the session, I will be posting problems in the comments for the session 1 day in advance.