Trees
A Tree $T$ is a Graph that:
Trees can be
- Ranked or Unranked
- Ordered or Unordered
Ranked Trees
A tree is ‘‘ranked’’ if you know in advance how many children a node has
- Binary Trees are trees with rank 2 (see Binary Search Trees)
A tree is unranked if you don’t know in advance the number of children
Ordered Trees
A tree is ‘‘ordered’’ if the order of children matters
For example,
