#define analogPin A2
#define leds 4 

int ledPins[] = {0, 1, 2, 3};

void setup() {
    for (uint8_t i = 0; i < leds; i++)
      pinMode(ledPins[i], OUTPUT);
}

void loop() {
  uint16_t sensorValue = analogRead(analogPin);
  // uint8_t ledLevel = (sensorValue * leds) / 1023;
  uint8_t ledLevel = map(sensorValue, 0, 1023, 0, leds);

  for (uint8_t i = 0; i < leds; i++) 
    digitalWrite(ledPins[i], (i < ledLevel) ? HIGH : LOW);

  delay(1);
}