What is inorder or in order?

Inorder, also known as in-order traversal or sequence, is a technique used for traversing a binary tree data structure. It is a depth-first search algorithm that visits each node in the tree in order. In inorder traversal, the left subtree is visited first, followed by the root node and then the right subtree.

In computer science, inorder traversal is used for various applications such as searching for a specific node or value, printing out the tree in a specific order, or evaluating expressions in a binary expression tree. It is a popular technique used in the implementation of data structures and algorithms, particularly in the field of artificial intelligence and machine learning.

Inorder traversal has a time complexity of O(n), where n is the number of nodes in the tree. It is a simple and efficient algorithm, and its output can be easily checked for correctness.