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        riddles >> hard >> Sink the sub
        
(Message started by: Ralph on Sep 30^th, 2007, 5:03pm)

Title: Sink the sub
Post by Ralph on Sep 30^th, 2007, 5:03pm

Howdy, I stumbled on this site via a blog post--another way for me to procrastinate, I reckon. Anyway, I'm a bit stumped by the Sink the Sub (http://www.ocf.berkeley.edu/~wwu/riddles/hard.shtml#sinkTheSub) riddle and was wondering if anyone had any hints as to how to solve this. It would be appreciated.

Update: I swear I searched for "Sink the sub", "sink", and "sub" to no avail, yet I just found this

http://www.ocf.berkeley.edu/~wwu/cgi-bin/yabb/YaBB.cgi?board=riddles_hard;action=display;num=1028142186

in the unsolved hard riddle sticky.

Title: Re: Sink the sub
Post by Ralph on Sep 30^th, 2007, 5:18pm

Sorry about that. I sure haven't made a very good first impression. :-/

Title: Re: Sink the sub
Post by FiBsTeR on Sep 30^th, 2007, 6:30pm

I remember reading the answer on here somewhere, and I think it went like this:

Let f(A,B,t) = At + B, then simply drop the torpedos at every t like this:

t=1: f(0,0,1)

t=2: f(-1,0,2)
t=3: f(0,-1,3)
t=4: f(-1,-1,4)

t=5: f(0,1,5)
t=6: f(1,0,6)
t=7: f(1,1,7)

t=8: f(-1,1,8)
t=9: f(1,-1,9)

t=10: f(0,-2,10)
...

If the velocity of the sub is p and its original position q, then eventually, for some t, A=p and B=q, and thus f(A,B,t)=f(p,q,t)=pt+q=pt+q, and the sub is sunk.

Title: Re: Sink the sub
Post by temporary on Feb 12^th, 2008, 11:16pm

0 0 0, 0 0 1, 0 1 0, 1 0 0, 1 0 1, 0 1 1, 1 1 0, 1 1 1, 0 0 2...