<p>You are given two strings <code>order</code> and <code>s</code>. All the characters of <code>order</code> are <strong>unique</strong> and were sorted in some custom order previously.</p>
<p>Permute the characters of <code>s</code> so that they match the order that <code>order</code> was sorted. More specifically, if a character <code>x</code> occurs before a character <code>y</code> in <code>order</code>, then <code>x</code> should occur before <code>y</code> in the permuted string.</p>
<p>Return <em>any permutation of </em><code>s</code><em> that satisfies this property</em>.</p>
<p><strong>Explanation: </strong><code>"a"</code>, <code>"b"</code>, <code>"c"</code> appear in order, so the order of <code>"a"</code>, <code>"b"</code>, <code>"c"</code> should be <code>"c"</code>, <code>"b"</code>, and <code>"a"</code>.</p>
<p>Since <code>"d"</code> does not appear in <code>order</code>, it can be at any position in the returned string. <code>"dcba"</code>, <code>"cdba"</code>, <code>"cbda"</code> are also valid outputs.</p>
<p><strong>Explanation: </strong> The characters <code>"b"</code>, <code>"c"</code>, and <code>"a"</code> from <code>order</code> dictate the order for the characters in <code>s</code>. The character <code>"d"</code> in <code>s</code> does not appear in <code>order</code>, so its position is flexible.</p>
<p>Following the order of appearance in <code>order</code>, <code>"b"</code>, <code>"c"</code>, and <code>"a"</code> from <code>s</code> should be arranged as <code>"b"</code>, <code>"c"</code>, <code>"a"</code>. <code>"d"</code> can be placed at any position since it's not in order. The output <code>"bcad"</code> correctly follows this rule. Other arrangements like <code>"dbca"</code> or <code>"bcda"</code> would also be valid, as long as <code>"b"</code>, <code>"c"</code>, <code>"a"</code> maintain their order.</p>
