Longest Consecutive Sequence LeetCode solution in C++

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class Solution {
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 public:
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  int longestConsecutive(vector<int> &nums) {
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    set<int> hashSet;
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    int longestConsecutiveSequence = 0;
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    for (auto it : nums) {
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      hashSet.insert(it);
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    }
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    for (auto it : nums) {
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      if (!hashSet.count(it - 1)) {
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        int count = 1;
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        while (hashSet.count(it + count)) ++count;
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        longestConsecutiveSequence = max(count, longestConsecutiveSequence);
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      }
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    }
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    return longestConsecutiveSequence;
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  }
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};