Описание тега tree
A tree is a widely-used data structure that emulates a hierarchical tree-like structure with a set of linked nodes.
A tree is a data structure where each node has a number of child nodes. By starting at the first node (called the root), one can use a decision algorithm to determine which of the children of the current node is the most appropriate for the next processing or traversal step.
Operations on trees include insert, delete, traverse and find. The algorithms for these methods are usually recursive, starting from the root node and recursively calling its left and right child.
Below is an example of binary-tree, in which each node has up to two child nodes:
Because large portions of the remaining nodes are culled away with each decision, properly balanced trees typical yield logarithmic time lookups, inserts, and deletes when used for storage.