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$ curl repovive.com/roadmaps/data-structures/link-cut-trees/rotate-with-update

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$ curl repovive.com/roadmaps/data-structures/link-cut-trees/rotate-with-update

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Rotate with Update - Link-Cut Trees | Data Structures | Repovive

Repovive.

Data Structures19 sections · 729 units49h total

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Rotate with Update

Maintaining aggregates

Update aggregates after rotation:

function rotate(x)
 p := x.parent
 g := p.parent

 if x = p.left then
 p.left := x.right
 if x.right then x.right.parent := p
 x.right := p
 else
 p.right := x.left
 if x.left then x.left.parent := p
 x.left := p

 p.parent := x
 x.parent := g

 if g is not null then
 if p = g.left then g.left := x
 else if p = g.right then g.right := x
 // else: p was root of aux tree, x inherits path-parent

 pushUp(p)
 pushUp(x)

function pushUp(x)
 x.subtreeSum := x.value
 x.subtreeSize := 1
 if x.left then
 x.subtreeSum := x.subtreeSum + x.left.subtreeSum
 x.subtreeSize := x.subtreeSize + x.left.subtreeSize
 if x.right then
 x.subtreeSum := x.subtreeSum + x.right.subtreeSum
 x.subtreeSize := x.subtreeSize + x.right.subtreeSize