repeated-substring-pattern.md

<p>Given a non-empty string check if it can be constructed by taking a substring of it and appending multiple copies of the substring together. You may assume the given string consists of lowercase English letters only and its length will not exceed 10000.</p>

<p>&nbsp;</p>

<p><b>Example 1:</b></p>

<pre>
<b>Input:</b> &quot;abab&quot;
<b>Output:</b> True
<b>Explanation:</b> It&#39;s the substring &quot;ab&quot; twice.
</pre>

<p><b>Example 2:</b></p>

<pre>
<b>Input:</b> &quot;aba&quot;
<b>Output:</b> False
</pre>

<p><b>Example 3:</b></p>

<pre>
<b>Input:</b> &quot;abcabcabcabc&quot;
<b>Output:</b> True
<b>Explanation:</b> It&#39;s the substring &quot;abc&quot; four times. (And the substring &quot;abcabc&quot; twice.)
</pre>