Leaf node: a node with no child nodes (that is, a degree of 0) in the tree, which is just a terminal node on any branch of the binary tree. It is called a leaf node, or simply "leaf". A leaf refers to a node with a degree of 0, also known as a terminal node.

Nodes include all nodes except leaf nodes, root nodes and intermediate nodes.

Take the following figure as an example:

Leaf nodes only include C, D and E, so the number of leaf nodes in this tree is 3.

The calculation of the number of nodes should include all nodes, namely A, B, C, D and E, so the number of nodes is 5.

Leaf node is a concept in discrete mathematics. Nodes in the tree that have no child nodes (that is, the degree is 0) are called leaf nodes, which are referred to as "leaves" for short. A leaf refers to a node with a degree of 0, also known as a terminal node.

Example:

If the degree of a tree is 4 and the number of nodes with degrees 1, 2, 3 and 4 are 4, 2, 1 and 1 respectively, what is the number of leaf nodes of the tree?

Solution: Because the total number of nodes in any tree = degree+1, so:

n0+4+2+ 1+ 1 =(n0 * 0+ 1 * 4+2 * 2+3 * 1+4 * 1)+ 1

So: n0=8

Where: n0 represents a leaf node.

References:

Baidu encyclopedia-leaf node