思路：排序，如果重叠，更新right 为max(right, curVal), 不重叠就加入res,需要单独考虑最后一次，因为每次都是在下一次遍历开始时判断是否加入res，因此 当 i==size()时，单独考虑

	static bool cmp(const vector<int>& v1, const vector<int>& v2){
        return v1 < v2;
    }
public:
    vector<vector<int>> merge(vector<vector<int>>& intervals) {
        sort(intervals.begin(), intervals.end(), cmp);
        int right = intervals[0][1];
        int left = intervals[0][0];

        vector<vector<int>> res;
        // for(auto i : intervals) {
        //     cout << i[0] << " " << i[1] << endl;
        // }

        vector<int> tmp;
        tmp.push_back(left);
        for(int i = 1; i <= intervals.size(); i++) {
            if(i == intervals.size()) {
                tmp.push_back(right);
                res.push_back(tmp);
                break;
            }
            // cout << i << " " << right << " ";
            if(right < intervals[i][0]) {
                tmp.push_back(right);
                res.push_back(tmp);
                tmp.clear();
                left = intervals[i][0];
                right = intervals[i][1];
                tmp.push_back(left);
            } else {
                right = max(right, intervals[i][1]);

            } 
            cout << endl;;
        }
        return res;
    }