Patricia tree

(data structure)

Definition: A compact representation of a trie in which any node that is an only child is merged with its parent.

Also known as radix tree.

Generalization (I am a kind of ...)

Specialization (... is a kind of me.)
suffix tree.

See also compact DAWG.

Note: A compact directed acyclic word graph (DAWG) merges common suffix trees to save additional space.

A radix tree is taken to be a binary Patricia tree.

Author: SE


Net-Patricia (Perl and C) is a C implementation with a Perl API. C prototyping tools, cprops (C), is a threaded implementation (find trie.c). py-radix (Python). insert (C), search (C).

More information

Donald R. Morrison, PATRICIA - Practical Algorithm to Retrieve Information Coded in Alphanumeric, Journal of the ACM, 15(4):514-534, October 1968.

Go to the Dictionary of Algorithms and Data Structures home page.

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

Entry modified 1 December 2010.
HTML page formatted Tue Dec 6 16:16:32 2011.

Cite this as:
Stefan Edelkamp, "Patricia tree", in Dictionary of Algorithms and Data Structures [online], Paul E. Black, ed., U.S. National Institute of Standards and Technology. 1 December 2010. (accessed TODAY) Available from:

to NIST home page