LeetCode101: 187. Repeated DNA Sequences

class Solution {
public:
	vector<string> findRepeatedDnaSequences(string s) {
		int left = 0;
		unordered_set<string> results;
		unordered_set<string> hset;

		for (auto right = 9; right < s.size(); right++) {
			string sub(s, left, 10);
			if (hset.find(sub) != hset.end()) {
				results.insert(sub);
			}
			hset.insert(sub);
			left++;
		}

		return vector<string>(results.begin(), results.end());
	}
};