Day of the Year

Given a string date representing a Gregorian calendar date formatted as YYYY-MM-DD, return the day number of the year.

LeetCode Problem - 1154

import java.time.Year;

class Solution {

    // Method to calculate the day of the year for a given date in the format "yyyy-mm-dd"
    public int dayOfYear(String date) {
        // Extract the year, month, and day from the date string
        int year = Integer.valueOf(date.substring(0, 4)); 
        int month = Integer.valueOf(date.substring(5, 7)); 
        int day = Integer.valueOf(date.substring(8, 10));

        // Determine if the year is a leap year and set February days accordingly
        int feb = 28;
        if (Year.of(year).isLeap()) feb = 29;

        // Array holding the number of days in each month
        int[] months = {31, feb, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

        // Initialize total days of the year with the given day
        int totalDaysOfYear = day;

        // Add the days of the previous months to the total
        for (int i = month - 2; i >= 0; i--) {
            totalDaysOfYear += months[i];
        }

        // Return the total number of days since the start of the year
        return totalDaysOfYear;
    }
}