About
The term tree order describes how a tree is traversed.
It can also be a graph data structures, selecting an arbitrary node as the root.
Type
h
/ | \
/ | \
d e g
/|\ |
/ | \ f
a b c
The traversals are classified by the order in which the nodes are visited:
- breadth-first order (hdegabcf). known also as breadht-first search 1) - All the nodes of depth 0 are returned, then depth 1, then 2, and so on.
- closest-first order (degcfab)
- depth-first order
- pre-order left (h d a b c e g f),
- pre-order right (h g f e d c b a)
- post-order left (a b c d e f g h),
Not for a tree (directed algorithm)
Example
Java
- Impkement a Guava tree traverser
/* Node is an object of your implementation with a getChildren function */
TreeTraverser<Node> traverser = new TreeTraverser<Node>() {
@Override
public Iterable<Task> children(Object node) {
return node.getChildren();
}
};
Node root = ....
Then you can iterate over the tree with a for loop:
- in breadth-first order
for (Task task : traverser.breadthFirstTraversal(root)) { ... }
- in Preorder
for (Task task : traverser.preOrderTraversal(root)) { ... }
- in postorder
for (Task task : traverser.postOrderTraversal(root)) { ... }