Solution.java

/**
 * 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<Interval> merge(List<Interval> intervals) {
        int n=intervals.size();
        int[] starts=new int[n],ends=new int[n];
        for(int i=0;i<n;i++){
            starts[i]=intervals.get(i).start;
            ends[i]=intervals.get(i).end;
        }
        Arrays.sort(starts);
        Arrays.sort(ends);
        List<Interval> res= new ArrayList<>();
        for(int i=0,j=0;i<n;i++){
            if((i == (n - 1)) || (starts[i + 1] > ends[i])){
                res.add(new Interval(starts[j],ends[i]));
                j=i+1;
            }
        }
        return res;
    }
}