Tree Traversal

Internal

• Tree Concepts

In-Order

In-order traversal means to recursively visit the left branch, the node itself, and then the right branch (in order). In-order tree traversal can be used to print a binary search tree node keys in sorted order.

let r = root of the search tree with subtrees TL and TR
recurse of TL # by recursion/induction, prints out keys of TL in increasing order
print out r's key
recurse of TR # by recursion/induction, prints out keys of TR in increasing order

The running time is O(n).

Pre-Order

Pre-order tree traversal means to first visit (process) the current node, then branches, starting with the left branch and continuing with the right branch.