Timeline for 3 Numbers on Hats, A = B + C
Current License: CC BY-SA 3.0
11 events
| when toggle format | what | by | license | comment | |
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| Mar 21, 2018 at 7:24 | comment | added | votbear | Ah right, euclid's algorithm. I knew this formula reminded me of something :P | |
| Mar 21, 2018 at 4:33 | vote | accept | Max Wang | ||
| Mar 21, 2018 at 4:32 | comment | added | Max Wang | You're good. I was originally looking for an explicit explanation of why the recursion you gave always terminates but looking at it again, it seems obvious. I didn't see it at first because the way I solved this myself was the reverse: I started with all values X=Y(1,1;2,2;3,3...etc) and showed that every positive integer pair can be built from one of these "seeds". And I think you're right about the simplification being better as that causes the second question to neatly reduce to "what is the runtime of Euclid's Algorithm". | |
| Mar 21, 2018 at 2:53 | history | edited | votbear | CC BY-SA 3.0 |
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| Mar 21, 2018 at 2:45 | comment | added | votbear | I added some extra explanation, but i don't know if that helps at all, haha. At some point it feels like i'm just explaining something trivial. And you're right, it can definitely deviate by more than one iteration, fixed that part. Still, i kind of disagree with 'more natural to understand'. Having them submit their answer all at once (e.g. using paper or the like) feels pretty understandable imo, and is definitely worth making the problem much simpler rather than adding the complexity of possibly less iterations based on the ordering. | |
| Mar 21, 2018 at 2:40 | history | edited | votbear | CC BY-SA 3.0 |
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| Mar 20, 2018 at 21:06 | comment | added | Max Wang | Nice! You're pretty much there, I'd just like a little bit more rigor with regards to showing why your reasoning in the third spoiler block applies to all positive integers.(also I think there's a typo in the explanation of case 5). As for the second part, with the question as currently stated the number of iterations can deviate by more than 1 from your formula, though it would be correct if I implemented your suggestion. I agree that the question might be improved by your proposal but I felt like this way was more natural to understand and reason about. | |
| Mar 20, 2018 at 9:57 | history | edited | votbear | CC BY-SA 3.0 |
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| Mar 20, 2018 at 8:22 | history | edited | votbear | CC BY-SA 3.0 |
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| Mar 20, 2018 at 8:14 | history | edited | votbear | CC BY-SA 3.0 |
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| Mar 20, 2018 at 8:05 | history | answered | votbear | CC BY-SA 3.0 |