310.cpp

class Solution {
public:
    vector<vector<int>> merge(vector<vector<int>>& intervals) {
        int n=intervals.size(),i;
        sort(intervals.begin(),intervals.end());
        vector<vector<int>> ans;  
        int start=intervals[0][0];
        int end=intervals[0][1];
         for(i=1;i<n;i++)
        {
            if(intervals[i][0]<=end)
            {
                end=max(end,intervals[i][1]);
            }
            else
            {
              
                ans.push_back({start,end});
                start=intervals[i][0];
                end=intervals[i][1];
            }
        }
     ans.push_back({start,end});
        return ans;
    }
};