1154. Day of the Year

Problem

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

  Example 1:

Input: date = "2019-01-09"
Output: 9
Explanation: Given date is the 9th day of the year in 2019.

Example 2:

Input: date = "2019-02-10"
Output: 41

  Constraints:

• date.length == 10

• date[4] == date[7] == '-', and all other date[i]'s are digits

• date represents a calendar date between Jan 1st, 1900 and Dec 31th, 2019.

Solution (Java)

class Solution {
    public int dayOfYear(String date) {
        int[] monthDays = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
        String[] dateArr = date.split("-");
        int year = Integer.parseInt(dateArr[0]);
        int month = Integer.parseInt(dateArr[1]);
        int day = Integer.parseInt(dateArr[2]);
        int dayCount = 0;
        boolean leapYear = ((year % 4 == 0) && (year % 100 != 0)) || (year % 400 == 0);
        for (int i = 1; i < month; i++) {
            dayCount += monthDays[i];
        }
        dayCount += day;
        if (leapYear && month > 2) {
            dayCount++;
        }
        return dayCount;
    }
}

Explain:

nope.

Complexity:

• Time complexity : O(n).
• Space complexity : O(n).