Tree

A tree represents hierarchical data with nodes connected by parent-child relationships. A tree has one root and no cycles. Filesystems, menus, and syntax trees are common examples.

The node structure from Linked list has one successor per node. A tree extends that idea to parent-child groups, but the help desk requirements have not introduced a hierarchy yet.

root
├── documents
└── images

In a balanced binary search tree, lookup, insertion, and removal are usually O(log n). An unbalanced tree can degrade to O(n). Traversals such as depth-first search visit nodes in preorder, inorder, or postorder.

Do not introduce a tree just because it is available. Choose it only when the requirement is genuinely hierarchical.

See Tree examples for runnable examples in supported programming languages.