LeetCode-in-Java
1185. Day of the Week
Easy
Given a date, return the corresponding day of the week for that date.
The input is given as three integers representing the day, month and year respectively.
Return the answer as one of the following 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”
Constraints:
- The given dates are valid dates between the years
1971and2100.
Solution
public class Solution {
public String dayOfTheWeek(int day, int month, int year) {
int counter = 0;
for (int i = 1971; i < year; i++) {
if (isLeapYear(i)) {
counter += 366;
} else {
counter += 365;
}
}
for (int i = 1; i < month; i++) {
counter += dayOfMonth(i);
}
for (int i = 1; i <= day; i++) {
counter += 1;
}
if (isLeapYear(year) && month > 2) {
counter++;
}
switch (counter % 7) {
case 1:
return "Friday";
case 2:
return "Saturday";
case 3:
return "Sunday";
case 4:
return "Monday";
case 5:
return "Tuesday";
case 6:
return "Wednesday";
default:
return "Thursday";
}
}
private boolean isLeapYear(int year) {
return ((year % 4 == 0) && (year % 100 != 0)) || year % 400 == 0;
}
private int dayOfMonth(int month) {
switch (month) {
case 1:
case 3:
case 5:
case 7:
case 8:
case 10:
case 12:
return 31;
case 4:
case 6:
case 9:
case 11:
return 30;
default:
return 28;
}
}
}