Medium data structure and algorithm practice puzzle.
Given meetings as [start, end], return the fewest rooms needed to hold them all. A meeting can start in a room right as another ends. The answer is the most meetings happening at the same time. Sort the start times and end times separately. Walk the starts. Each one needs a room, but first free up every room whose meeting has already ended.
Solve it three ways: snap the jigsaw pieces together, fill in the blanks, or type it from scratch against the tests. This one is free.
Every line of the solution comes with a note explaining why it is there, and a step by step replay shows the code running. At level 3, where you type it yourself, you can ask for an AI mock interview on this problem that ends with a hiring manager's scorecard.
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