Have you ever been curious about what red coders do during a contest in order to solve all problems within a contest? How they think? How they debug?
You can check out my screencast here: CodeChef January Lunchtime 2020 Division 1 - YouTube (note that it’s almost 3 hours long)
I don’t describe solutions very well while doing the contest though, look at January Lunchtime 2020 Post-Contest Discussion Stream if you are looking for solutions instead.