postorder traversal

(algorithm)

Definition: Process all nodes of a tree by recursively processing all subtrees, then finally processing the root.

Also known as postfix traversal.

Generalization (I am a kind of ...)
tree traversal, depth-first search.

See also in-order traversal, preorder traversal, level-order traversal, Cupif-Giannini tree traversal.

Note: For instance, if the "processing" is just printing, a tree is printed as "(first subtree) (second subtree) ... (last subtree) root". Here is pseudocode for a binary tree:

 postorder(tree)
 begin
     if tree is null, return;

     postorder(tree.left_subtree);
     postorder(tree.right_subtree);
     print(tree.root);
 end 

Author: PEB

More information

animation (Java)

If you have suggestions, corrections, or comments, please get in touch with Paul Black.

Entry modified 24 August 2017.
HTML page formatted Mon May 11 15:07:57 2026.

Cite this as:
Paul E. Black, "postorder traversal", in Dictionary of Algorithms and Data Structures [online], Vreda Pieterse and Paul E. Black, eds. 24 August 2017. (accessed TODAY) Available from: /HTML/postorderTraversal.html