【DataStrcutre】Introduction and description of Binary Trees

[Definitions]

Here is the recursive definition of a binary tree:

A binary tree is either the empty set or a triple T = (x,L,R), where x is a node and L and R are disjoint binary trees, neither of which contains.

The node x is called the root of the tree T, and the subtrees L and R are called the left subtree and the right subtree of T rooted at x.

Here is an equivalent, nonerecursive defination for binary trees:

A binay tree is an ordered tree in which every internal node has degree 2.

Full Binary Trees

A binary tree is said to be full if itls leaves are at the same level and every interior node has two children.