56. Merge Intervals

Description

Given a collection of intervals, merge all overlapping intervals.

For example,
Given [1,3],[2,6],[8,10],[15,18],
return [1,6],[8,10],[15,18].

    class Solution {
        public List<Interval> merge(List<Interval> intervals) {

            int n = intervals.size();
            int
 
[] starts = new int[n];
            int[] 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;
        }
    }