题解 | 今年的第几天？

难点在“闰年”的定义。若非整百年份能被4整除则为闰年；整百年数当且仅当能被400整除时才是闰年。

只要写出每过一个月对应一年过了多少天，根据输入查对应的表即可。

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        while (in.hasNextInt()) {
            int year = in.nextInt();
            int month = in.nextInt();
            int day = in.nextInt();
            // 判断闰年
            boolean isLunarYear = year % 4 == 0 && !(year % 100 == 0 && year % 400 != 0);
            // 节点表
            int[] lunarYearDayCount = new int[] {0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366};
            int[] normalYearDayCount = new int[13];
            for (int i = 0; i <= 12; i++) {
                normalYearDayCount[i] = lunarYearDayCount[i];
            }
            for (int i = 2; i <= 12; i++) {
                normalYearDayCount[i]--;
            }

            // 查表
            if (isLunarYear) {
                System.out.println(lunarYearDayCount[month - 1] + day);
            } else {
                System.out.println(normalYearDayCount[month - 1] + day);
            }
        }
    }
}