吃于y总
int months[13] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
bool check(int date)
{
int year = date / 10000;
int month = date % 10000 / 100;
int day = date % 100;
if (!month || month >= 13 || !day) return false;
if (month != 2 && day > months[month]) return false;
if (month == 2)
{
bool leap = year % 4 == 0 && year % 100 || year % 400 == 0;
if (day > 28 + leap) return false;
}
return true;
}