CS:3330 (22C:031) Algorithms, Spring 2018

Tree

Depth

Let v be a node of a tree T. The depth of v is the number of ancestors of v,
excluding v itself. Note that this definition implies that the depth of the root of T
is 0. The depth of a node v can also be recursively defined as follows:
• If v is the root, then the depth of v is 0.
• Otherwise, the depth of v is one plus the depth of the parent of v. 

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Algorithm depth(T, v):
if T.isRoot(v) then
return 0
else
return 1 + depth(T, T.parent(v))

using the following recursive definition of the height of a node v in a tree T:
• If v is an external node, then the height of v is 0.
• Otherwise, the height of v is one plus the maximum height of a child of v.
The height of a tree T is the height of the root of T. 

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Algorithm height(T, v):
if T.isExternal(v) then
return 0
else
h = 0
for each w ∈ T.children(v) do
h = max(h, height(T,w))
return 1 + h

Preorder Traversal

Postorder Traversal