算法提高 日期计算

           import java.util.Scanner;
           public class Main {
           static int a[][] ={ { 0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
            { 0, 31,28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 } };
           public static voidmain(String[] args) {
            Scanner input = new Scanner(System.in);
           int y = input.nextInt();
           int m = input.nextInt();
           int d = input.nextInt();
           int week = Day(y, m, d) - Day(2011, 11, 11);
           if (week > 0)
            System.out.println((4 week % 7) % 7 1);
           else {
           for (int i= 1; i <= 7; i)
           if ((i - 1 -week % 7) % 7 1== 5) {
            System.out.println(i);
           break;
            }
            }
            }
           public staticboolean isRun(int year) {
           if (year % 4 == 0&& year % 100 != 0 || year % 400 ==0)
            returntrue;
           return false;
            }
           public static intDay(int y, int m, int d) {
           int ans = 0;
           for (int i = 1; i < y; i)
            ans =calDay(i);
           int index = 0;
           if (!isRun(y))
            index = 1;
           for (int i = 1; i < m; i)
            ans =a[index][i];
            ans = d;
           return ans;
            }
           public static intcalDay(int year) {
           int index = 0;
           if (!isRun(year))
            index = 1;
           int tot = 0;
           for (int i = 1; i <= 12; i)
            tot =a[index][i];
           return tot;
            }
           }