Ricardo Aráoz wrote: > > Ok, I'll bite. > First, the instructions make no sense. There is no left and right! In a > railroad there is forward and backwards, and these are relative to the > directions the cars dropped at which I assume will be random. So "move > fwd" has the same meaning as "move bck" as there is no common reference > system (at least you mentioned none). > > Anyway the program is obvious: > > label1 > Move one car's length fwd > If car is next to a parachute Goto label2 > do nothing > goto label1 > > label2 > Move one car's length fwd > goto label2 > > > This will give you 75% probability that the cars meet (they will never > meet if they land facing opposite ways). > > When the problem was posed to me there was a diagram in which left and right made sense. Your observation is also good.
The program is obvious - well eventually. It took me several iterations before I was able to see the obvious. My preferred solution is the one Michael Langford offered as this makes no assumptions about execution time: #Same assumptions as 1, but assumes: # NO-OP takes no time to execute # so we have to move the car around more # to slow it down #Approach: Two steps forward, one step back, # until we're sure we're the chasing car PROG2: GO LEFT GO LEFT GO RIGHT IF AT PARACHUTE GOTO FASTER GOTO PROG2 FASTER: GO LEFT GOTO FASTER _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor