# 1185 Day of the Week

new Date() 基本語法請記熟

LeetCode

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"}.

input: 給 day、month、year
output: 印出是禮拜幾

Example 1:

Input: day = 31, month = 8, year = 2019
Output: "Saturday"  243  245%7 = 

Example 2:

Input: day = 18, month = 7, year = 1999
Output: "Sunday"  199
Example 3:

Input: day = 15, month = 8, year = 1993
Output: "Sunday"   227
 

Constraints:
1971 1 1 Friday
The given dates are valid dates between the years 1971 and 2100.
*/

/**
 * @param {number} day
 * @param {number} month
 * @param {number} year
 * @return {string}
 */
var dayOfTheWeek = function(day, month, year) {}

如何解

基本上我覺得不用內建 js new Date() 根本超難 = =

var dayOfTheWeek = function(day, month, year) {
    let Weeks = [ "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"];
    return Weeks[new Date(`${year}-${month}-${day}`).getDay()];

    // 2019 9 2  Monday  245  2019
};

console.log(dayOfTheWeek(19, 9, 2019))  
// faster than 87.80% of JavaScript online submissions

學到什麼

new Date() 平常其實很少用到，至少基本的要記起來