题解 | #今年的第几天？# #Java#

import java.util.Scanner;
import java.util.HashSet;
import java.util.Set;
import java.util.Arrays;


// 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 year = in.nextInt();
            int month = in.nextInt();
            int day = in.nextInt();
            int res = getDays(year,month,day);
            System.out.println(res);
        }
    }

    public static int getDays(int year, int month, int day) {
        Set<Integer> bigMonth = new HashSet<Integer>(Arrays.asList(1, 3, 5, 7, 8, 10,12));
        Set<Integer> smallMonth = new HashSet<Integer>(Arrays.asList(4, 6, 9, 11));
        int res = 0;
        // 判断是否是闰年
        if(year % 400 == 0 || ( year % 4 == 0 && year % 100 != 0)){
            // 如果是闰年，且当月大于二月，则加一天
            if(month > 2){
                res += 1;
            }  
        }
        for(int i = 0;i < month-1;i++ ){
            int tm = i+1;
            if(tm == 2){
                res += 28;
            }else{
                if(bigMonth.contains(tm)){
                    res += 31;
                }else{
                    res += 30;
                }
            }
        }
        return res+day;
    }
}