Longest Consecutive Sequence

class Solution {
public:
    map<int, pair<int, int> > seq; //used to store the answers for each number
                                    //first max, second min;

    int max;

    int longestConsecutive(vector<int> &num) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        max = 0;
        seq.clear();
        
        for (int i=0; i<num.size(); ++i)
        {
            seq[num[i]] = make_pair(1, 1);
        }
              
        int cur;

        for (auto i=seq.begin(); i!=seq.end(); ++i)
        {
            cur = i->first;
            if (seq.find(cur+1) != seq.end()) //hit
            {
                //make the left ++
                int curL = cur-seq[cur].second+1;
                seq[curL].first += seq[cur+1].first;
                //make the right ++
                int curR = cur+1+seq[cur+1].first-1;
                seq[curR].second += seq[cur].second;
            }    
        }

        for (auto i=seq.begin(); i!=seq.end(); ++i)
        {
            cur = i->first;
            if (seq[cur].first+seq[cur].second-1 > max)
            {
                max = seq[cur].first+seq[cur].second-1;
            }
        }


        return max;
    }
};