Each problem is worth 10 points. You have just been awarded a contract to revamp the signaling system on the New York City subway lines.
Tracks are one-way only.
You decide to place a combinational circuit under each section of track. The input P is 1 if there is a train in this section. The inputs and are received from the next section. The outputs G , Y and R should be a 1 to light the green, yellow, and red signals, respectively, for this section of track. The outputs and are passed back to the previous section.