Check if One String Swap Can Make Strings Equal
<p>You are given two strings <code>s1</code> and <code>s2</code> of equal length. A <strong>string swap</strong> is an operation where you choose two indices in a string (not necessarily different) and swap the characters at these indices.</p>

<p>Return <code>true</code> <em>if it is possible to make both strings equal by performing <strong>at most one string swap </strong>on <strong>exactly one</strong> of the strings. </em>Otherwise, return <code>false</code>.</p>

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

<pre>
<strong>Input:</strong> s1 = &quot;bank&quot;, s2 = &quot;kanb&quot;
<strong>Output:</strong> true
<strong>Explanation:</strong> For example, swap the first character with the last character of s2 to make &quot;bank&quot;.
</pre>

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

<pre>
<strong>Input:</strong> s1 = &quot;attack&quot;, s2 = &quot;defend&quot;
<strong>Output:</strong> false
<strong>Explanation:</strong> It is impossible to make them equal with one string swap.
</pre>

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

<pre>
<strong>Input:</strong> s1 = &quot;kelb&quot;, s2 = &quot;kelb&quot;
<strong>Output:</strong> true
<strong>Explanation:</strong> The two strings are already equal, so no string swap operation is required.
</pre>

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

<ul>
	<li><code>1 &lt;= s1.length, s2.length &lt;= 100</code></li>
	<li><code>s1.length == s2.length</code></li>
	<li><code>s1</code> and <code>s2</code> consist of only lowercase English letters.</li>
</ul>
Hash Table; String; Counting
func areAlmostEqual(s1 string, s2 string) bool {
	cnt := 0
	var c1, c2 byte
	for i := range s1 {
		a, b := s1[i], s2[i]
		if a != b {
			cnt++
			if cnt > 2 || (cnt == 2 && (a != c2 || b != c1)) {
				return false
			}
			c1, c2 = a, b
		}
	}
	return cnt != 1
}