题解 | #获得月份天数#

import java.util.Scanner;
import java.util.Arrays;
public class Main{
    public static void main(String[] args){
       Scanner sc=new Scanner(System.in);
        while(sc.hasNext()){  //循环多组输入
          
            int year=sc.nextInt();
        int month=sc.nextInt();
          //下面判断是否为闰年
       boolean flg=(year%4==0 && year%100!=0) || (year%400==0);
          //31天的月份
        String[] str1=new String[]{"1","3","5","7","8","10","12"};
          //30天的月份
        String[] str2=new String[]{"4","6","9","11"};
          //逐个判断
        if(flg && month==2){
            System.out.println(29);
        }else if(flg && Arrays.asList(str1).contains(month+"")){
            System.out.println(31);
        }else if(flg && Arrays.asList(str2).contains(month+"")){
            System.out.println(30);
        }else if(!flg && month==2){
            System.out.println(28);
        }else if(!flg && Arrays.asList(str1).contains(month+"")){
             System.out.println(31);
        }else if(!flg && Arrays.asList(str2).contains(month+"")){
             System.out.println(30);
        }
        }
        
    }
}