class Solution {
public:
    bool isIntersects(const pair<int, int> &p1, const pair<int, int > &p2) {
        return (p1.second >= p2.first );
    }
    vector<vector<int>> merge(vector<vector<int>>& intervals) {
        vector< vector<int > > result;
        if (intervals.size() == 0) return result;

        sort( intervals.begin(), intervals.end() );

        int l = intervals[0][0];
        int r = intervals[0][1];

        for (size_t i = 1; i < intervals.size(); i++) {
            if ( isIntersects( {l, r} , {intervals[i][0], intervals[i][1] } ) ) {
                r = max( r, intervals[i][1] );
            } else {
                result.push_back( { l, r } );
                l = intervals[i][0];
                r = intervals[i][1];
            }
        }

        result.push_back( { l, r } );

        return result;
    }
};