题解 | 计算日期到天数转换

import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNextInt()) { // 注意 while 处理多个 case
            int a = in.nextInt();
            int b = in.nextInt();
            int c = in.nextInt();

            int extra = 0, result = 0;
            if (a % 100 == 0) {
                int m = a / 100;
                if(m % 4 == 0) extra = 1;
            } else {
                if (a % 4 == 0) extra = 1;
            }

            switch (b) {
                case 12:
                    result = 365 - 31 + c + extra;
                    break;
                case 11:
                    result = 365 - 31 - 30 + c + extra;
                    break;
                case 10:
                    result = 365 - 2 * 31 - 30 + c + extra;
                    break;
                case 9:
                    result = 365 - 2 * 31 - 2 * 30 + c + extra;
                    break;
                case 8:
                    result = 365 - 3 * 31 - 2 * 30 + c + extra;
                    break;
                case 7:
                    result = 365 - 4 * 31 - 2 * 30 + c + extra;
                    break;
                case 6:
                    result = 365 - 4 * 31 - 3 * 30 + c + extra;
                    break;
                case 5:
                    result = 365 - 5 * 31 - 3 * 30 + c + extra;
                    break;
                case 4:
                    result = 365 - 5 * 31 - 4 * 30 + c + extra;
                    break;
                case 3:
                    result = 365 - 6 * 31 - 4 * 30 + c + extra;
                    break;
                case 2:
                    result = 365 - 6 * 31 - 4 * 30 - 28 + c;
                    break;
                case 1:
                    result = 365 - 7 * 31 - 4 * 30 - 28 + c;
                    break;
            }

            System.out.println(result);
        }
    }
}