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$ curl repovive.com/roadmaps/data-structures/interval-trees/building-the-tree

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$ curl repovive.com/roadmaps/data-structures/interval-trees/building-the-tree

Repovive

Building the Tree - Interval Trees | Data Structures | Repovive

Repovive.

Data Structures19 sections · 729 units49h total

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Building the Tree

Recursive construction

To build an interval tree:

function buildIntervalTree(intervals)
 if intervals is empty then
 return null

 // Find midpoint of all endpoints
 allPoints := collect all low and high values
 mid := median of allPoints

 // Partition intervals
 center := intervals containing mid
 left := intervals entirely < mid
 right := intervals entirely > mid

 node := new IntervalTreeNode()
 node.mid := mid
 node.center := center (sorted by low and by high)
 node.left := buildIntervalTree(left)
 node.right := buildIntervalTree(right)
 return node

Using the median ensures balanced trees. Time: $O(n \log n)$ . Space: $O(n)$ .