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adt: update docstrings for IntervalTree.Insert and IntervalTree.find #20015

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ahrtr merged 1 commit into from
May 23, 2025
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adt: update docstrings for IntervalTree.Insert and IntervalTree.find #20015

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40 changes: 8 additions & 32 deletions pkg/adt/interval_tree.go
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Original file line number Diff line number Diff line change
Expand Up @@ -434,38 +434,11 @@ func (ivt *intervalTree) createIntervalNode(ivl Interval, val any) *intervalNode
}
}

// TODO: make this consistent with textbook implementation
//
// "Introduction to Algorithms" (Cormen et al, 3rd ed.), chapter 13.3, p315
//
// RB-INSERT(T, z)
//
// y = T.nil
// x = T.root
//
// while x ≠ T.nil
// y = x
// if z.key < x.key
// x = x.left
// else
// x = x.right
//
// z.p = y
//
// if y == T.nil
// T.root = z
// else if z.key < y.key
// y.left = z
// else
// y.right = z
//
// z.left = T.nil
// z.right = T.nil
// z.color = RED
//
// RB-INSERT-FIXUP(T, z)

// Insert adds a node with the given interval into the tree.
//
// Cormen "Introduction to Algorithms", Chapter 14 Exercise 14.3.5.
// The algorithm follows Cormen "Introduction to Algorithms", Chapter 14 Exercise 14.3.5.
// for modifying an interval tree structure to support exact interval matching.
func (ivt *intervalTree) Insert(ivl Interval, val any) {
y := ivt.sentinel
z := ivt.createIntervalNode(ivl, val)
Expand Down Expand Up @@ -714,7 +687,10 @@ func (ivt *intervalTree) Visit(ivl Interval, ivv IntervalVisitor) {
ivt.root.visit(&ivl, ivt.sentinel, func(n *intervalNode) bool { return ivv(&n.iv) })
}

// find the exact node for a given interval
// find the exact node for a given interval. The implementation follows
// Cormen "Introduction to Algorithms", Chapter 14 Exercise 14.3.5. for
// exact interval matching. The search runs in O(log n) time on an n-node
// interval tree.
func (ivt *intervalTree) find(ivl Interval) *intervalNode {
x := ivt.root
// Search until hit sentinel or exact match.
Expand Down