One Edit Distance
<p>Given two strings <code>s</code> and <code>t</code>, return <code>true</code> if they are both one edit distance apart, otherwise return <code>false</code>.</p>

<p>A string <code>s</code> is said to be one distance apart from a string <code>t</code> if you can:</p>

<ul>
	<li>Insert <strong>exactly one</strong> character into <code>s</code> to get <code>t</code>.</li>
	<li>Delete <strong>exactly one</strong> character from <code>s</code> to get <code>t</code>.</li>
	<li>Replace <strong>exactly one</strong> character of <code>s</code> with <strong>a different character</strong> to get <code>t</code>.</li>
</ul>

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

<pre>
<strong>Input:</strong> s = &quot;ab&quot;, t = &quot;acb&quot;
<strong>Output:</strong> true
<strong>Explanation:</strong> We can insert &#39;c&#39; into s&nbsp;to get&nbsp;t.
</pre>

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

<pre>
<strong>Input:</strong> s = &quot;&quot;, t = &quot;&quot;
<strong>Output:</strong> false
<strong>Explanation:</strong> We cannot get t from s by only one step.
</pre>

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

<ul>
	<li><code>0 &lt;= s.length, t.length &lt;= 10<sup>4</sup></code></li>
	<li><code>s</code> and <code>t</code> consist of lowercase letters, uppercase letters, and digits.</li>
</ul>
Two Pointers; String
func isOneEditDistance(s string, t string) bool {
	m, n := len(s), len(t)
	if m < n {
		return isOneEditDistance(t, s)
	}
	if m-n > 1 {
		return false
	}
	for i := range t {
		if s[i] != t[i] {
			if m == n {
				return s[i+1:] == t[i+1:]
			}
			return s[i+1:] == t[i:]
		}
	}
	return m == n+1
}