Cuttleshock
Inkling Commander
- Joined
- Apr 1, 2016
- Messages
- 459
Maybe I'm not trying hard enough to follow, but I don't fully get it... what I'm confident of is that your method is different to mine.
No, okay, here. What I did was along the lines of setting up simultaneous recursive equations in three probabilities: p(n), q(n) and r(n). p(n) is the probability that, after 2n presses, the state is 10. q(n) is the probability that the state is 01 and r(n), 11. p(0) = q(0) = r(0) =1/3. If the state is 10, there's probability 1/2 that it'll terminate after one more press and 1/2 that it'll go on to the next multiple of 2 (because it definitely can't terminate after two presses, as the first switch would necessarily be ON then). If the state is 01, there's a probability 1/4 that it'll terminate after 2 presses and 3/4 that it'll go on. If 11, again, 1/4 that it'll terminate after 2 presses, 3/4 that it'll go on. We can get a recursive definition for p(n+1) in terms of p(n), q(n) and r(n) and similarly for the other two states. This leads us to several unwieldy infinite geometric sequences which very much require us to evaluate something like the infinite sum of the reciprocals of the Fibonacci numbers.
Extending that to the case with three switches, it begins to get very unpleasant, as you'd need seven recurrently-defined probabilities; again, though, it works by the logic that each one can only terminate at its final 1 after 3n clicks (e.g. 101 being the situation after 3n clicks means that you only have a chance of switching it off at 3n+3 clicks). But I guess I could give it a shot tomorrow. Sleepy right now.
No, okay, here. What I did was along the lines of setting up simultaneous recursive equations in three probabilities: p(n), q(n) and r(n). p(n) is the probability that, after 2n presses, the state is 10. q(n) is the probability that the state is 01 and r(n), 11. p(0) = q(0) = r(0) =1/3. If the state is 10, there's probability 1/2 that it'll terminate after one more press and 1/2 that it'll go on to the next multiple of 2 (because it definitely can't terminate after two presses, as the first switch would necessarily be ON then). If the state is 01, there's a probability 1/4 that it'll terminate after 2 presses and 3/4 that it'll go on. If 11, again, 1/4 that it'll terminate after 2 presses, 3/4 that it'll go on. We can get a recursive definition for p(n+1) in terms of p(n), q(n) and r(n) and similarly for the other two states. This leads us to several unwieldy infinite geometric sequences which very much require us to evaluate something like the infinite sum of the reciprocals of the Fibonacci numbers.
Extending that to the case with three switches, it begins to get very unpleasant, as you'd need seven recurrently-defined probabilities; again, though, it works by the logic that each one can only terminate at its final 1 after 3n clicks (e.g. 101 being the situation after 3n clicks means that you only have a chance of switching it off at 3n+3 clicks). But I guess I could give it a shot tomorrow. Sleepy right now.