public class Lab10sol {
    public static void main(String[] args) {
	TrafficSignal ts = new TrafficSignal(); // create a new TrafficSignal
	ts.runOneCycle();                       // run one cycle of the Bulbs
	System.out.println(ts);                 // output how much time the cycle used
    }
} // Class Lab10sol

class TrafficSignal {
    private Bulb red = new Bulb("R", 120);     // create red light Bulb
    private Bulb green = new Bulb("G", 120);   // create green light Bulb
    private int time;  // amount of time used in one cycle
    
    // Activate the red and green Bulbs in succession:
       public void runOneCycle() {
	   red.runLight();           // run the red Bulb
	   time += red.getTime();    // add the amount of time from red
	   green.runLight();         // run the green Bulb
	   time += green.getTime();  // add the amount of time from green
       }
    
    // Return a String description of how much time the TrafficSignal has run:
       public String toString() {
	   return "The traffic signal ran for "+time+" secs.";
       }

} // Class TrafficSignal

class Bulb {
    private String color; // color of the light Bulb
    private int duration; // amount of time light Bulb designed to stay on (sec)
    private boolean on;   // whether or not Bulb is on: $true$ means on
    private int time;     // amount of time Bulb has been on (sec)

    // Create a new Bulb with color and duration:
       public Bulb(String color, int duration) {
	   this.color = color;        // set color of Bulb
	   this.duration = duration ; // set duration of Bulb
       }

    // Return the amount of time that the Bulb was on:
       public int getTime() { return time; }

    // Turn the current Bulb off and on:
       private void turnOff() { on=false ; }
       private void turnOn()  { on=true ; }
    
    // Run the current Bulb for the duration of time, after which the Bulb will turn 	
    // off. During the operation, the Bulb may randomly turn off after 30 seconds:
       public void runLight() {
	   
	   turnOn();   // turn Bulb on	  
	   time = 30;  // Bulb stays on at least 30 sec
	   
	   // Operate Bulb for remainder of duration. Has 1% chance of shutting off
	   // at beginning or end of a second:
	   shutOffAtRandom();
	   while (on && time < duration) {
	       time++;
	       shutOffAtRandom();
	   }
	   turnOff(); // Bulb shuts off after duration is over
       }

    // Turn the Bulb off about 1% of the time:
       private void shutOffAtRandom() {
	   if (MyMath.myRandom(1,100)==1)
	       turnOff();
       }
    
} // Class Bulb

class MyMath {
    public static int myRandom(int low, int high) {
	return (int) (Math.random()*(high-low+1)) + (int) low;
    }
}