leetcode-problemset/算法题/longest-substring-of-all-vowels-in-order.html

<p>A string is considered <strong>beautiful</strong> if it satisfies the following conditions:</p>

<ul>
	<li>Each of the 5 English vowels (<code>&#39;a&#39;</code>, <code>&#39;e&#39;</code>, <code>&#39;i&#39;</code>, <code>&#39;o&#39;</code>, <code>&#39;u&#39;</code>) must appear <strong>at least once</strong> in it.</li>
	<li>The letters must be sorted in <strong>alphabetical order</strong> (i.e. all <code>&#39;a&#39;</code>s before <code>&#39;e&#39;</code>s, all <code>&#39;e&#39;</code>s before <code>&#39;i&#39;</code>s, etc.).</li>
</ul>

<p>For example, strings <code>&quot;aeiou&quot;</code> and <code>&quot;aaaaaaeiiiioou&quot;</code> are considered <strong>beautiful</strong>, but <code>&quot;uaeio&quot;</code>, <code>&quot;aeoiu&quot;</code>, and <code>&quot;aaaeeeooo&quot;</code> are <strong>not beautiful</strong>.</p>

<p>Given a string <code>word</code> consisting of English vowels, return <em>the <strong>length of the longest beautiful substring</strong> of </em><code>word</code><em>. If no such substring exists, return </em><code>0</code>.</p>

<p>A <strong>substring</strong> is a contiguous sequence of characters in a string.</p>

<p>&nbsp;</p>
<p><strong>Example 1:</strong></p>

<pre>
<strong>Input:</strong> word = &quot;aeiaaio<u>aaaaeiiiiouuu</u>ooaauuaeiu&quot;
<strong>Output:</strong> 13
<b>Explanation:</b> The longest beautiful substring in word is &quot;aaaaeiiiiouuu&quot; of length 13.</pre>

<p><strong>Example 2:</strong></p>

<pre>
<strong>Input:</strong> word = &quot;aeeeiiiioooauuu<u>aeiou</u>&quot;
<strong>Output:</strong> 5
<b>Explanation:</b> The longest beautiful substring in word is &quot;aeiou&quot; of length 5.
</pre>

<p><strong>Example 3:</strong></p>

<pre>
<strong>Input:</strong> word = &quot;a&quot;
<strong>Output:</strong> 0
<b>Explanation:</b> There is no beautiful substring, so return 0.
</pre>

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

<ul>
	<li><code>1 &lt;= word.length &lt;= 5 * 10<sup>5</sup></code></li>
	<li><code>word</code> consists of characters <code>&#39;a&#39;</code>, <code>&#39;e&#39;</code>, <code>&#39;i&#39;</code>, <code>&#39;o&#39;</code>, and <code>&#39;u&#39;</code>.</li>
</ul>