Leetcode relaxation question - day of the week

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        package algorithm.dayOfTheWeek;
        

        
/**
        
 * 1185.  The day of the week 
        
 *  Give you a date , Please design an algorithm to determine which day of the week it corresponds to .
        
 *
        
 *  Enter three integers ：day、month  and  year, Each represents a day 、 month 、 year .
        
 *
        
 *  The result you return must be one of these values  {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"}.
        
 *
        
 *
        
 *
        
 *  Example  1：
        
 *
        
 *  Input ：day = 31, month = 8, year = 2019
        
 *  Output ："Saturday"
        
 *  Example  2：
        
 *
        
 *  Input ：day = 18, month = 7, year = 1999
        
 *  Output ："Sunday"
        
 *  Example  3：
        
 *
        
 *  Input ：day = 15, month = 8, year = 1993
        
 *  Output ："Sunday"
        
 *
        
 *
        
 *  Tips ：
        
 *
        
 *  The date given must be  1971  To  2100  Effective date between years .
        
 */
        
public class dayOfTheWeek {
        
    public static String dayOfTheWeek(int day, int month, int year) {
        

        
        String[] week = {"Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"};
        
        int[] monthDays = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30};
        
        // Calculate the number of days this year , Plus leap year 
        
        int days = 365 * (year-1971)+(year-1969)/4;
        
        // Calculate this month's 
        
        for (int i = 0; i < month-1; i++) {
        
            days+=monthDays[i];
        
        }
        
        if(year%400==0 ||(year %4==0 &&year%100!=0)){
        
           days+=1;
        
        }
        
        // Calculate how many days have passed this month 
        
        days+=day;
        
        //1971.1.1 It's Friday ,+3 Convert to Monday 
        
        return week[(days+3)%7];
        
    }
        

        
    public static void main(String[] args) {
        
        int day = 17, month = 1, year = 2022;
        
        System.out.println(dayOfTheWeek(day,month,year));
        
    }
        
}
       
       

        
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