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$ curl repovive.com/roadmaps/data-structures/interval-trees/point-query

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$ curl repovive.com/roadmaps/data-structures/interval-trees/point-query

Repovive

Point Query - Interval Trees | Data Structures | Repovive

Repovive.

Data Structures19 sections · 729 units49h total

Open in Course

Point Query

Finding intervals at point

To find all intervals containing point $p$ :

function queryPoint(node, p)
 if node is null then
 return empty list

 result := []

 if p < node.mid then
 // Check center intervals sorted by low
 for interval in node.centerByLow
 if interval.low <= p then
 result.add(interval)
 else
 break
 result.addAll(queryPoint(node.left, p))

 else if p > node.mid then
 // Check center intervals sorted by high
 for interval in node.centerByHigh
 if interval.high >= p then
 result.add(interval)
 else
 break
 result.addAll(queryPoint(node.right, p))

 else // p == node.mid
 result.addAll(node.center)

 return result

Time: $O(\log n + k)$ where $k$ is the number of results.