Day of the Week
<p>Given a date, return the corresponding day of the week for that date.</p>

<p>The input is given as three integers representing the <code>day</code>, <code>month</code> and <code>year</code> respectively.</p>

<p>Return the answer as one of the following values&nbsp;<code>{&quot;Sunday&quot;, &quot;Monday&quot;, &quot;Tuesday&quot;, &quot;Wednesday&quot;, &quot;Thursday&quot;, &quot;Friday&quot;, &quot;Saturday&quot;}</code>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> day = 31, month = 8, year = 2019
<strong>Output:</strong> &quot;Saturday&quot;
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> day = 18, month = 7, year = 1999
<strong>Output:</strong> &quot;Sunday&quot;
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> day = 15, month = 8, year = 1993
<strong>Output:</strong> &quot;Sunday&quot;
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li>The given dates are valid dates between the years <code>1971</code> and <code>2100</code>.</li>
</ul>
Math
func dayOfTheWeek(d int, m int, y int) string {
	if m < 3 {
		m += 12
		y -= 1
	}
	c := y / 100
	y %= 100
	w := (c/4 - 2*c + y + y/4 + 13*(m+1)/5 + d - 1) % 7
	weeks := []string{"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"}
	return weeks[(w+7)%7]
}