Well first off I think any company using leetcode as a screen for their candidates is out of the minds. (It seems to be a popular way to be out of their mind b

Well first off I think any company using leetcode as a screen for their candidates is out of the minds. (It seems to be a popular way to be out of their mind but that doesn’t make it a good idea. :)) But implementing a trivial unoptimized solution for the problem you linked is feasible enough in 45 minutes. Talking idly through how one might tweak the algorithm to optimize, or adopting an optimized algorithm if one occurs to you as you’re implementing the basic one also seems fine. If they want a tested, optimized, and implemented novel solution in that period, they are testing for people who grind leetcode and not people who are good engineers. I would have likely saved myself the time by not applying to a company like that in the first place! Screens should generally focus on finding candidates worth talking more with. Leetcode exercises are low value for that. If you want to learn anything, don’t work there. Work at a place that selects for better talent than mindlessly picking leetcode exercises as a screener. You will learn more, you will be at a company that does better, etc. (I have never screened a candidate using leetcode. I have never been screened using leetcode. The one time someone tried to screen me using stupid questions like this I finished our session and promptly terminated the process when they called me back for a future round because while I may have passed their screen they emphatically did not pass my screen. I don’t study for interviews, nor do I expect people who I interview to study. Nothing I’m going to ask is something you can cram about the night before. This isn’t a college midterm.)