Problem E — Sensor Optimization Dilemma 2 from last Atcoder Beginner Contest had a new idea that people in the comments section claimed to be pretty well known. However, this was my first time encountering such an idea, and I figured it'd be the same for a lot of people, so I created a video editorial talking about this fractional greedy idea (with a twist).

https://youtu.be/Tha0WO2FVXE?si=cxuKQbIiaVaGIpt1

Credits to Igor_Parfenov for sharing his wonderful approach in the comments.