2020蓝桥杯省赛javaA 回文日期

public class 回文日期 {
    public static void main(String[] args) {
        // 先判断是不是回文串在判断是不是日期
        get();
    }

    public static void get(){
        Scanner sr = new Scanner(System.in);
        String s = sr.nextLine();

        int date = Integer.parseInt(s);

        int next = 0;
        int nextAB = 0;
        int times = 0;
        int firstNext = 0;

        for (date++;date <=89991231; date++){
            if (huiwen(date) && isDate(date)) {
                next = date;
                times++;
                if (isABhuiwen(date)) {
                    nextAB = date;
                    break;
                }
                if (times == 1)
                    firstNext = date;
            }
        }
        System.out.println(Integer.toString(firstNext));
        System.out.println(Integer.toString(nextAB));
    }

    private static boolean isABhuiwen(int date) {
        //首先一定是回文了，只需要判断第一位是否和第三位相等，第二位是否和第四问相等即可。
        String s = Integer.toString(date);
        if(s.charAt(0) == s.charAt(2) && s.charAt(1) == s.charAt(3))
            return true;
        return false;
    }

    private static boolean isDate(int date) {
        int year = date/10000;
        int month = (date/100) %100;
        int day = date % 100;
        if (month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12){
            if (day <= 31) return true;
        }
        else if (month == 2 || month == 4 || month == 6 || month == 9 || month == 11){
            if ((year % 4 == 0 && year % 100 != 0) || year % 4 == 0){
                if (day <= 29) {
                    return true;
                } else {
                    if (day <= 28)
                        return true;
                }
            }
        }
        return false;
    }

    private static boolean huiwen(int date) {
        String s = Integer.toString(date);

        int i = 0;
        int j = s.length()-1;
        while (i <= j ){
            if (s.charAt(i) != s.charAt(j))
                return false;
            i++;
            j--;
        }
        return true;
    }
}