cognitive psychology. PhD 
Combinatorics problem: you're arranging 10 people (A .. J) in a row. A and B must sit next to each other. How many arrangements? How could writing this problem as a program help scaffold the problem-solving process?
Show this thread
-
I would reframe it as arranging 9 units: (AB) and C .. J. The result is the number of permutations of 9 things × 2 — one set for AB and another for BA. I find a lot of tricky problems get simpler if you can find a non-obvious thing to treat as a first-class entity.
Agreed! That's the "additive" solution I mention (see down in the thread). My question: what is a general strategy to help people reach this solution from the problem statement?
-
-
I don't think there is one. The problem is that "insight" is fragile: if you instead asked "where A and B are NOT adjacent", I don't think you can use the same constructive solution. You could instead say it's 10! - (9!*2), but that's another leap of insight
-
And if we instead perturbed to "A and B have *exactly one* person between them", I don't see what the constructive solution would be at all
- Show replies
New conversation -
Loading seems to be taking a while.
Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.