HDOJ(HDU) 2133 What day is it(认识下Java的Calendar类---日期类)

package cn.hncu.acm;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Scanner;

public class P2133 {


    public static void main(String[] args) throws ParseException {
        String[] week = {"Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday"};
        int yuee[][]={{0,31,28,31,30,31,30,31,31,30,31,30,31},{0,31,29,31,30,31,30,31,31,30,31,30,31}};
        Scanner sc = new Scanner(System.in);
        while(sc.hasNext()){
            int y = sc.nextInt();
            int m = sc.nextInt();
            int d = sc.nextInt();
             if((yunn(y)==0&&m==2&&d==29)||m>12||d>yuee[yunn(y)][m]||m==0||d==0||y==0)
               {
                   System.out.println("illegal");
                   continue;
               }
             /*
            //题目是有问题的
            //1 1 1 应该是星期六，具体为什么看网上资料。
            //这个题目要求已知1 1 1是星期一
            String[] week = {"","Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday"};
            String strTime = y+"-"+m+"-"+d;
            SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
            Calendar c = Calendar.getInstance();
            c.setTime(format.parse(strTime));
            System.out.println(week[c.get(Calendar.DAY_OF_WEEK)]);

            */
             int s=0;
             for(int i=1;i<y;i++){
                 if(yunn(i)==1){
                     s+=366;
                 }else{
                     s+=365;
                 }
             }

             for(int i=1;i<m;i++){
                 s+=yuee[yunn(y)][i];
             }
             s+=d;
             s=s%7;
             System.out.println(week[s]);
        }
    }


    public static int yunn(int xx)
    {
        if((xx%4==0&&xx%100!=0)||(xx%400==0))
            return 1;//是闰年
        return 0;//不是闰年
    }
}