// 定义LED灯的引脚
const int red1 = 2;
const int yellow1 = 3;
const int green1 = 4;
const int red2 = 5;
const int yellow2 = 6;
const int green2 = 7;

// 定义按钮的引脚
#define button1 8
#define button2 9

// 定义状态
enum State {
  RED_GREEN,
  YELLOW_RED,
  GREEN_RED,
  RED_YELLOW
};

// 定义当前状态和上一个状态
State currentState = RED_GREEN;
State previousState = RED_GREEN;

void setup() {
  // 设置LED灯为输出模式
  pinMode(red1, OUTPUT);
  pinMode(yellow1, OUTPUT);
  pinMode(green1, OUTPUT);
  pinMode(red2, OUTPUT);
  pinMode(yellow2, OUTPUT);
  pinMode(green2, OUTPUT);

  // 设置按钮为输入模式
  pinMode(button1, INPUT);
  pinMode(button2, INPUT);

  // 初始化LED灯为关闭状态
  digitalWrite(red1, LOW);
  digitalWrite(yellow1, LOW);
  digitalWrite(green1, LOW);
  digitalWrite(red2, LOW);
  digitalWrite(yellow2, LOW);
  digitalWrite(green2, LOW);
}

void loop() {
  // 检测按钮状态
  int buttonState1 = digitalRead(button1);
  int buttonState2 = digitalRead(button2);

  // 更新状态
  if (buttonState1 == HIGH) {
    currentState = RED_GREEN;
  } else if (buttonState2 == HIGH) {
    currentState = GREEN_RED;
  } else {
    switch (previousState) {
      case RED_GREEN:
        currentState = RED_YELLOW;
        break;
      case YELLOW_RED:
        currentState = RED_GREEN;
        break;
      case GREEN_RED:
        currentState = YELLOW_RED;
        break;
      case RED_YELLOW:
        currentState =GREEN_RED;
        break;
    }
  }

  // 更新LED灯状态
  switch (currentState) {
    case RED_GREEN:
      digitalWrite(red1, HIGH);
      digitalWrite(yellow1, LOW);
      digitalWrite(green1, LOW);
      digitalWrite(red2, LOW);
      digitalWrite(yellow2, LOW);
      digitalWrite(green2, HIGH);
      delay(3000);
      break;
    case YELLOW_RED:
      digitalWrite(red1, LOW);
      digitalWrite(yellow1, HIGH);
      digitalWrite(green1, LOW);
      digitalWrite(red2, HIGH);
      digitalWrite(yellow2,LOW);
      digitalWrite(green2, LOW);
      delay(500);
      break;
    case GREEN_RED:
      digitalWrite(red1, LOW);
      digitalWrite(yellow1, LOW);
      digitalWrite(green1, HIGH);
      digitalWrite(red2, HIGH);
      digitalWrite(yellow2, LOW);
      digitalWrite(green2, LOW);
      delay(3000);
      break;
    case RED_YELLOW:
      digitalWrite(red1, HIGH);
      digitalWrite(yellow1, LOW);
      digitalWrite(green1, LOW);
      digitalWrite(red2, LOW);
      digitalWrite(yellow2, HIGH);
      digitalWrite(green2, LOW);
      delay(500);
      break;
  }

  // 更新上一个状态
  previousState = currentState;
}