Description

In order traversal, is the traversal of a binary tree where we count the left most node first and work our way right.
?

Reach for when

You care about order - the node comes between its subtrees, producing a left-to-right sequence.

Runtime

O(n)

Visualization

Pseudocode

InOrder(node):
	if node is null:
		return
	InOrder(node.left)
	save node.value
	InOrder(node.right)

Code

def traverse(node, answer=[]):
	if not node:
		return answer

	traverse(node.left, answer)
	answer.append(node.value)
	traverse(node.right, answer)
	return answer