Solving a problem from an interview about merge intervals

merge_intervals.dart

List<List<int>> mergeIntervals(List<List<int>> intervals) {
  //The intervals should be sorted
  //Creating a clone of intervals if we don't want the original intervals to be sorted
  final clonedIntervals = List.from(intervals)
    ..sort((a, b) => a.first.compareTo(b.first));

  List<List<int>> mergedIntervals = [];
  mergedIntervals.add(clonedIntervals.first);

  for (final interval in clonedIntervals) {
    final lastMergedIntervals = mergedIntervals.last;

    if (lastMergedIntervals.last < interval.first) {
      mergedIntervals.add(interval);
      continue;
    }

    if (lastMergedIntervals.last < interval.last) {
      mergedIntervals.remove(lastMergedIntervals);
      mergedIntervals.add([lastMergedIntervals.first, interval.last]);
    }
  }

  return mergedIntervals;
}

void main() {
  final intervals = [[2, 3], [2, 6], [8, 10], [15, 18]];
  final mergedIntervals = mergeIntervals(intervals);
  
  print("Original intervals: $intervals");
  print("Merged intervals: $mergedIntervals");
}