public IntervalTreeNode <T> GetIntervalTree(IEnumerable <Interval <T> > intervals)
{
if (intervals == null)
{
return(null);
}
T[] pointsArray = GetPoints(intervals);
T median = ArrayUtils.GetMedian <T>(pointsArray);
IList <Interval <T> > left = new List <Interval <T> >();
IList <Interval <T> > right = new List <Interval <T> >();
IList <Interval <T> > current = new List <Interval <T> >();
foreach (Interval <T> interval in intervals)
{
if (interval.Contains(median))
{
current.Add(interval);
}
else
{
if (median.CompareTo(interval.Start) < 0)
{
left.Add(interval);
}
else
{
right.Add(interval);
}
}
}
Interval <T>[] currentIntervals = current.ToArray <Interval <T> >();
Array.Sort(currentIntervals);
IntervalTreeNode <T> currentNode = new IntervalTreeNode <T>(median, currentIntervals);
currentNode.left = GetIntervalTree(left);
currentNode.right = GetIntervalTree(right);
return(currentNode);
}
private static IntervalTreeNode Build(IList <Interval> intervals, int i, int j)
{
if (i > j)
{
return(null);
}
var mid = (i + j) / 2;
var root = new IntervalTreeNode(intervals[mid]);
root.Left = Build(intervals, i, mid - 1);
root.Right = Build(intervals, mid + 1, j);
var rangeBegin = root.Left?.Range.Begin ?? root.Value.Begin;
var rangeEnd = root.Right?.Range.End ?? root.Value.End;
root.Range = new Interval(rangeBegin, rangeEnd);
return(root);
}
private IEnumerable <Interval> GetOverlappingIntervals(IntervalTreeNode root, Interval interval)
{
if (root == null || !root.Range.Overlaps(interval))
{
yield break;
}
if (root.Value.Overlaps(interval))
{
yield return(root.Value);
}
foreach (var leftInterval in GetOverlappingIntervals(root.Left, interval))
{
yield return(leftInterval);
}
foreach (var rightInterval in GetOverlappingIntervals(root.Right, interval))
{
yield return(rightInterval);
}
}
