/** * Definition for an interval. * public class Interval { *     int start; *     int end; *     Interval() { start = 0; end = 0; } *     Interval(int s, int e) { start = s; end = e; } * } */class Solution {    public List
     
       merge(List
      
        intervals) {        List
       
         result = new ArrayList<>();        if (intervals == null || intervals.size() < 2) {            return intervals;        }        Collections.sort(intervals, new Comparator
        
         (){            @Override            public int compare(Interval i1, Interval i2) {                return i1.start - i2.start;            }        });        Interval current = intervals.get(0);        for (int i = 1; i < intervals.size(); i++) {            if (current.end >= intervals.get(i).start) {                current.end = Math.max(current.end, intervals.get(i).end);            } else {                result.add(current);                current = intervals.get(i);            }        }        result.add(current);        return result;    }}
        
       
      
     

 

 

1. Has to be sorted if originally not sorted.

2. When merge end point, it could be totally covered instead of intersect.