题解 | #日期差值#写个for循环计数就行

//Java版代码
import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String start = sc.next();
        String end = sc.next();
        int startYear = Integer.parseInt(start.substring(0, 4));
        int startMonth = Integer.parseInt(start.substring(4, 6));
        int startDay = Integer.parseInt(start.substring(6, 8));
        int endYear = Integer.parseInt(end.substring(0, 4));
        int endMonth = Integer.parseInt(end.substring(4, 6));
        int endDay = Integer.parseInt(end.substring(6, 8));
        int[] days = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
        int totalDay = 0;
        while (startYear < endYear || startYear == endYear && startMonth < endMonth ||
                startYear == endYear && startMonth == endMonth && startDay <= endDay) {
            if (startYear % 4 == 0 && startYear % 100 != 0 ||
                    startYear % 400 == 0) days[2] = 29;
            else days[2] = 28;
            startDay++;
            totalDay++;
            if (startDay > days[startMonth]) {
                startDay = 1;
                startMonth++;
                if (startMonth > 12) {
                    startMonth = 1;
                    startYear++;
                }
            }
        }
        System.out.println(totalDay);
    }
}
#Python版代码
from datetime import datetime
start_time = datetime.strptime(input(), '%Y%m%d')
end_time = datetime.strptime(input(), '%Y%m%d')
print((end_time - start_time).days + 1)