My logic went like this:
- we can shorten the run time by intercepting red after one check of the left bit to see if it points left
- if the left bit points right, we will need to check the right bit
- since there is a 50/50 chance that the right bit will require us to intercept a blue ball, there is no advantage to running a red ball through again
- if the second bit points right, intercept the blue ball, else, let it drain and release the final ball that will be intercepted.