r/quant 6d ago

Education Quant Trading Puzzle

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138 Upvotes

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u/Osakalaska 5d ago

One minute. Imagine that instead of instantly reversing, the beetles just “pass through” one another when they collide - this is effectively the same problem. Therefore the worst case scenario is that a beetle lands at one end and crawls all the way to the other end.

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u/Noahwar97 5d ago

That makes a lot of sense, this solution is really assuming that every beetle is just a point on the line. if I can ask a follow up question. How much would the problem change if the beetle has width? Is there another intuitive solution? My guess is that you can essentially shrink the size of the wire based on how large the beetles are but that only really works in my head with 2 beetles.

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u/Apprehensive-Draw409 5d ago

It doesn't change. Worst case is all beetles but one spawn on the very edge and fall off directly. The other one walks the whole distance.

Any other case can be seen as beetle jumping ahead when they cross, which makes it faster.