Reformat Date
<p>Given a <code>date</code> string in the form&nbsp;<code>Day Month Year</code>, where:</p>

<ul>
	<li><code>Day</code>&nbsp;is in the set <code>{&quot;1st&quot;, &quot;2nd&quot;, &quot;3rd&quot;, &quot;4th&quot;, ..., &quot;30th&quot;, &quot;31st&quot;}</code>.</li>
	<li><code>Month</code>&nbsp;is in the set <code>{&quot;Jan&quot;, &quot;Feb&quot;, &quot;Mar&quot;, &quot;Apr&quot;, &quot;May&quot;, &quot;Jun&quot;, &quot;Jul&quot;, &quot;Aug&quot;, &quot;Sep&quot;, &quot;Oct&quot;, &quot;Nov&quot;, &quot;Dec&quot;}</code>.</li>
	<li><code>Year</code>&nbsp;is in the range <code>[1900, 2100]</code>.</li>
</ul>

<p>Convert the date string to the format <code>YYYY-MM-DD</code>, where:</p>

<ul>
	<li><code>YYYY</code> denotes the 4 digit year.</li>
	<li><code>MM</code> denotes the 2 digit month.</li>
	<li><code>DD</code> denotes the 2 digit day.</li>
</ul>

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

<pre>
<strong>Input:</strong> date = &quot;20th Oct 2052&quot;
<strong>Output:</strong> &quot;2052-10-20&quot;
</pre>

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

<pre>
<strong>Input:</strong> date = &quot;6th Jun 1933&quot;
<strong>Output:</strong> &quot;1933-06-06&quot;
</pre>

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

<pre>
<strong>Input:</strong> date = &quot;26th May 1960&quot;
<strong>Output:</strong> &quot;1960-05-26&quot;
</pre>

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

<ul>
	<li>The given dates are guaranteed to be valid, so no error handling is necessary.</li>
</ul>
String
func reformatDate(date string) string {
	s := strings.Split(date, " ")
	day, _ := strconv.Atoi(s[0][:len(s[0])-2])
	months := " JanFebMarAprMayJunJulAugSepOctNovDec"
	month := strings.Index(months, s[1])/3 + 1
	year, _ := strconv.Atoi(s[2])
	return fmt.Sprintf("%d-%02d-%02d", year, month, day)
}