Merge Intervals

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].

Solution:

public List<Interval> merge(List<Interval> intervals) { if (intervals.size() == 0) { return intervals; } intervals.sort((i1, i2) -> Integer.compare(i1.start, i2.start)); List<Interval> result = new ArrayList<>(); int start = intervals.get(0).start; int end = intervals.get(0).end; for (Interval i : intervals) { if (i.start <= end) { end = Math.max(i.end, end); } else { result.add(new Interval(start, end)); start = i.start; end = i.end; } } result.add(new Interval(start, end)); return result; }