Arduino Code Combinations

const int LED=9;
const int BUTTON1=2;
const int BUTTON2=3;
const String CODE = "ABAB";

String rec = "";
String lastRec = "";
boolean lastButton1 = LOW;
boolean currentButton1 = LOW;

boolean lastButton2 = LOW;
boolean currentButton2 = LOW;

boolean ledOn = false;

void setup() {
  Serial.begin(9600);
  pinMode(LED,OUTPUT);
  pinMode(BUTTON1,INPUT);
  pinMode(BUTTON2,INPUT);
  Serial.println("Hello World");
}

boolean debounce(boolean last, int button)
{
  boolean current = digitalRead(button);
  
  if(last != current)
  {
    delay(5);
    current = digitalRead(button);
  }
  return current;
}

void loop() {
  
  currentButton1 = debounce(lastButton1,BUTTON1);
  
  if(lastButton1 == LOW && currentButton1 == HIGH)
  {
    rec+="A";
  }
  
  lastButton1 = currentButton1;
  
  currentButton2 = debounce(lastButton2,BUTTON2);
  
  if(lastButton2 == LOW && currentButton2 == HIGH)
  {
    rec+="B";
  }
  
  lastButton2 = currentButton2;
  
  if(rec.endsWith(CODE))
  {
    ledOn = true;
  }else
  {
    ledOn= false;
  }
  
  if(rec != "")
  {
    if(lastRec != rec) //only output rec if there is a change
    {
      Serial.println(rec);
      lastRec = rec;
    }
  }
  
  digitalWrite(LED,ledOn);
}