Formatted question description: https://leetcode.ca/all/1154.html

# 1154. Day of the Year (Easy)

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


Example 3:

Input: date = "2003-03-01"
Output: 60


Example 4:

Input: date = "2004-03-01"
Output: 61


Constraints:

• date.length == 10
• date == date == '-', and all other date[i]'s are digits
• date represents a calendar date between Jan 1st, 1900 and Dec 31, 2019.

Related Topics:
Math

## Solution 1.

// OJ: https://leetcode.com/problems/day-of-the-year/
// Time: O(1)
// Space: O(1)
class Solution {
const int days = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
bool isLeap(int y) {
return y % 4 == 0 && (y % 100 != 0 || y % 400 == 0);
}
public:
int dayOfYear(string date) {
int y = stoi(date.substr(0, 4)), m = stoi(date.substr(5, 2)), d = stoi(date.substr(8));
return (m > 2 && isLeap(y)) + accumulate(begin(days), begin(days) + m - 1, 0) + d;
}
};


Java

• class Solution {
public int dayOfYear(String date) {
String[] array = date.split("-");
int year = Integer.parseInt(array), month = Integer.parseInt(array), day = Integer.parseInt(array);
if (month == 1)
return day;
if (month == 2)
return 31 + day;
int leap = (year % 4 == 0 && year % 100 != 0 || year % 400 == 0) ? 1 : 0;
int dayOfYear = 31 + 28 + leap;
if (month > 3)
dayOfYear += 31;
if (month > 4)
dayOfYear += 30;
if (month > 5)
dayOfYear += 31;
if (month > 6)
dayOfYear += 30;
if (month > 7)
dayOfYear += 31;
if (month > 8)
dayOfYear += 31;
if (month > 9)
dayOfYear += 30;
if (month > 10)
dayOfYear += 31;
if (month > 11)
dayOfYear += 30;
dayOfYear += day;
return dayOfYear;
}
}

• // OJ: https://leetcode.com/problems/day-of-the-year/
// Time: O(1)
// Space: O(1)
class Solution {
const int days = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
bool isLeap(int y) {
return y % 4 == 0 && (y % 100 != 0 || y % 400 == 0);
}
public:
int dayOfYear(string date) {
int y = stoi(date.substr(0, 4)), m = stoi(date.substr(5, 2)), d = stoi(date.substr(8));
return (m > 2 && isLeap(y)) + accumulate(begin(days), begin(days) + m - 1, 0) + d;
}
};

• # 1154. Day of the Year
# https://leetcode.com/problems/day-of-the-year/

from datetime import datetime
​
class Solution:
def dayOfYear(self, date: str) -> int:
f = "%Y-%m-%d"
dt = datetime.strptime(date, f)
res = dt.timetuple().tm_yday

return res