const int greenLedPin = 2;
const int redLedPin = 3;
const int ldrPin = A0;
const int trigPin = 7;
const int echoPin = 6;

void setup() {
  // Initialize serial communication
  Serial.begin(9600);
  // Set LED pins as outputs
  pinMode(greenLedPin, OUTPUT);
  pinMode(redLedPin, OUTPUT);
  // Set trigger pin as output and echo pin as input
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
}

void loop() {
  // Create array to store sensor values
  int sensors[] = {1, 2, 3};
  
  for(int i = 0; i < 3; i++) {
    if(sensors[i] == 1) {
      int ldrValue = analogRead(ldrPin);
      if(ldrValue < 500) {
        digitalWrite(greenLedPin, HIGH);
        delay(1000);
        digitalWrite(greenLedPin, LOW);
      }
    } else if(sensors[i] == 2) {
      long duration, distance;
      digitalWrite(trigPin, LOW);
      delayMicroseconds(2);
      digitalWrite(trigPin, HIGH);
      delayMicroseconds(10);
      digitalWrite(trigPin, LOW);
      duration = pulseIn(echoPin, HIGH);
      distance = (duration / 2) / 29.1;
      if(distance < 20) {
        digitalWrite(redLedPin, HIGH);
        delay(1000);
        digitalWrite(redLedPin, LOW);
       
      }
    } else if(sensors[i] == 3) {
      digitalWrite(greenLedPin, HIGH);
      digitalWrite(redLedPin, HIGH);
      delay(1000);
      digitalWrite(greenLedPin, LOW);
      digitalWrite(redLedPin, LOW);
    }
  }
}