<p>The <strong>DNA sequence</strong> is composed of a series of nucleotides abbreviated as <code>&#39;A&#39;</code>, <code>&#39;C&#39;</code>, <code>&#39;G&#39;</code>, and <code>&#39;T&#39;</code>.</p>

<ul>
	<li>For example, <code>&quot;ACGAATTCCG&quot;</code> is a <strong>DNA sequence</strong>.</li>
</ul>

<p>When studying <strong>DNA</strong>, it is useful to identify repeated sequences within the DNA.</p>

<p>Given a string <code>s</code> that represents a <strong>DNA sequence</strong>, return all the <strong><code>10</code>-letter-long</strong> sequences (substrings) that occur more than once in a DNA molecule. You may return the answer in <strong>any order</strong>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<pre><strong>Input:</strong> s = "AAAAACCCCCAAAAACCCCCCAAAAAGGGTTT"
<strong>Output:</strong> ["AAAAACCCCC","CCCCCAAAAA"]
</pre><p><strong class="example">Example 2:</strong></p>
<pre><strong>Input:</strong> s = "AAAAAAAAAAAAA"
<strong>Output:</strong> ["AAAAAAAAAA"]
</pre>
<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= s.length &lt;= 10<sup>5</sup></code></li>
	<li><code>s[i]</code> is either <code>&#39;A&#39;</code>, <code>&#39;C&#39;</code>, <code>&#39;G&#39;</code>, or <code>&#39;T&#39;</code>.</li>
</ul>

#include <algorithm> // for find
#include <cstddef>   // for size_t
#include <iterator>  // for distance
#include <string>    // for basic_string, allocator, string, char_traits, hash
#include <vector>    // for vector

class Solution {
public:
	std::vector<std::string> findRepeatedDnaSequences(std::string s) // NOLINT
	{
		std::set<std::size_t> hashes;
		std::set<std::string> result;
		for (auto begin = s.cbegin(); begin != s.cend(); ++begin) {
			if (std::distance(begin, s.cend()) < 10) {
				break;
			}

			std::string substr = {begin, begin + 10};
			auto hash          = hashfunc(substr);
			if (!hashes.insert(hash).second) {
				result.insert(substr);
			}
		}

        std::vector<std::string> data;
        data.reserve(result.size());
        std::move(result.cbegin(), result.cend(), std::back_inserter(data));

		return data;
	}
private:
	std::hash<std::string> hashfunc{};
};
15521