inorderleft

Inorderleft is a term used in some programming contexts to denote a specific form of in-order traversal of a binary tree. In many codebases, it identifies an in-order traversal that processes left subtrees before the node and then the right subtree. Because in-order traversal by definition visits left before the root, "inorderleft" is often synonymous with the standard in-order traversal and is not standardized as a distinct algorithm in formal literature. The name is primarily found in source code, tutorials, or library APIs to differentiate from other traversal variants such as pre-order or post-order, or from left-imposed variants like inorderright used for emphasis.

A typical inorderleft traversal visits the left child, then the current node, then the right child. This can be implemented recursively or iteratively. Recursively: if node is null, return; inorderleft(node.left); visit(node); inorderleft(node.right). Iterative implementations use an explicit stack to emulate the recursion, pushing left descendants, visiting a node, then moving to the right subtree.

Complexity: Time O(n) for visiting all nodes; auxiliary space O(h), where h is the height of the tree, for recursive call stack or the explicit stack in iterative variants. Inorderleft is commonly used when the application requires outputs in nondecreasing order for BSTs or when left-to-right traversal is semantically meaningful.

See also: In-order traversal, Binary tree, Depth-first search.