<p>Return the number of <strong>distinct</strong> non-empty substrings of <code>text</code>&nbsp;that can be written as the concatenation of some string with itself (i.e. it can be written as <code>a + a</code>&nbsp;where <code>a</code> is some string).</p>

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

<pre>
<strong>Input:</strong> text = &quot;abcabcabc&quot;
<strong>Output:</strong> 3
<b>Explanation: </b>The 3 substrings are &quot;abcabc&quot;, &quot;bcabca&quot; and &quot;cabcab&quot;.
</pre>

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

<pre>
<strong>Input:</strong> text = &quot;leetcodeleetcode&quot;
<strong>Output:</strong> 2
<b>Explanation: </b>The 2 substrings are &quot;ee&quot; and &quot;leetcodeleetcode&quot;.
</pre>

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

<ul>
	<li><code>1 &lt;= text.length &lt;= 2000</code></li>
	<li><code>text</code>&nbsp;has only lowercase English letters.</li>
</ul>

class Solution:
    def distinctEchoSubstrings(self, text: str) -> int:
        n = len(text)
        used = set()
        for m in range(1, n):
            cur = 0
            s = set()
            for i in range(m - 1, - 1, - 1):
                cur <<= 5
                cur += (ord(text[i]) - ord('a') + 1)
                s.add(cur)
            cur = 0
            for i in range(m, n):
                cur += (ord(text[i]) - ord('a') + 1) << (5 * (i - m))
                if cur in s and cur not in used:
                    used.add(cur)
        return len(used)

18500