int ldr1 = 13;
int led1 = 16;
int led2 = 17;
int led3 = 5;
int led4 = 18;
int value1 = 0;
int value2 = 0;

void setup() {

  Serial.begin(9600);

  pinMode(led1, OUTPUT);
  pinMode(led2, OUTPUT);
  pinMode(led3, OUTPUT);
  pinMode(led4, OUTPUT);
}

void loop() {
  delay(100);
  value1 = analogRead(ldr1);
  Serial.print("value1:");
  Serial.print(value1);

  value2 = map(value1, 500, 3000, 0, 4);
  Serial.print(" value2:");
  Serial.println(value2);

  if (value2 == 4) {
    digitalWrite(led1, 0);
    digitalWrite(led2, 0);
    digitalWrite(led3, 0);
    digitalWrite(led4, 0);
  } else if (value2 == 3) {
    digitalWrite(led1, 1);
    digitalWrite(led2, 0);
    digitalWrite(led3, 0);
    digitalWrite(led4, 0);
  } else if (value2 == 2) {
    digitalWrite(led1, 1);
    digitalWrite(led2, 1);
    digitalWrite(led3, 0);
    digitalWrite(led4, 0);
  } else if (value2 == 1) {
    digitalWrite(led1, 1);
    digitalWrite(led2, 1);
    digitalWrite(led3, 1);
    digitalWrite(led4, 0);
  } else if (value2 == 0) {
    digitalWrite(led1, 1);
    digitalWrite(led2, 1);
    digitalWrite(led3, 1);
    digitalWrite(led4, 1);
  }
}