int led1[] = {26,27,14};
int led2[] = {19,18,5};
int swtch = 13;

void declare(int a[])
{
  for(int i=0;i < sizeof(a);i++)
  {
    pinMode(a[i], OUTPUT);
  }
}

void setup() {
  Serial.begin(115200);
  declare(led1);
  declare(led2);
  pinMode(swtch, INPUT_PULLUP);
}

void on(int a)
{
  digitalWrite(led1[a], HIGH);
  delay(10);
  digitalWrite(led2[a], HIGH);
}
void off(int a)
{
  digitalWrite(led1[a], LOW);
  digitalWrite(led2[a], LOW);
}
void blink(int a)
{
  on(a);
  delay(500);
  off(a);
}

void loop() {
  if (digitalRead(swtch) == HIGH)
  {
    blink(0);
    blink(1);
    blink(2);
  }
  else
  {
    off(0);
    off(1);
    off(2);
  }
}