Merge pull request #1 from charlesreid1/try-trie-tree
Try trie tree
|9 months ago|
|output||2 years ago|
|.gitignore||2 years ago|
|LICENSE||2 years ago|
|README.md||9 months ago|
|diff_by_n.py||9 months ago|
|diff_by_one_fixed.py||9 months ago|
|distinct.py||2 years ago|
|euclidean_distance.py||2 years ago|
|get_words.py||2 years ago|
|letter_coverage.py||2 years ago|
|letter_coverage_dbg.py||2 years ago|
|lexico.py||2 years ago|
|near_palindromes.py||2 years ago|
|palindromes.py||2 years ago|
|reverse_lexico.py||2 years ago|
|sgb-words.txt||2 years ago|
|stats.py||2 years ago|
|tries.py||9 months ago|
This repository contains Donald Knuth’s GraphBase list of five-letter words, as well as scripts to run various combinatoric experiments, graph algorithms, and other algorithms to explore the relationships among these words.
The list of words comes from  and is in the public domain.
A Python program that contains a method for getting all of the five letter words from a file, and that’s about it.
Exercises 26-37 of Knuth’s Volume 4 Fascile 0 are intended as a warm up to get to know the SGB five letter word list. Solutions to these exercises are listed below.
distinct.py- computes the number of SGB words containing exactly k distinct letters.
diff_by_one_fixed.py - (fixed 2019-03-09) computes the number of words in the SGB
that are off by a single letter in each position. An example is
Each corresponding letter is only different by one:
r -> s,
o->p, and so on.
This uses recursive backtracking to generate possible matches for each word, and
uses a hash table to check for their existence in the original word set.
There are 38 such pairs in the SGB.
Also see Five Letter Words on the charlesreid1.com wiki.
diff_by_n_fixed.py - (added 2019-03-10.) using the corrected approach (above) to
computing differences by 1, this generalizes the calculation to words that are different
by a distance
d for each letter position.
euclidean_distance.py - computes the euclidean distance between two words. This uses
the traditional Euclidean distance definition but reinterprets distance to mean edit distance.
lexico.py - find words that are sorted by lexicographic order (front to back, a-z).
palindromes.py - look for five letter words that are either a palindrome, or a palindrome pair.
diff_by_n.py - computes words in SGB that have an edit distance of n.
reverse_lexico.py - variation on
lexico.py that finds words whose letters are in
reverse lexicographic order.
letter_coverage.py - computes coverage of the alphabet (minimum number of words required
to provide X letters of the alphabet)
Knuth mentions, in the text, a couple of facts about how many words cover how much of the alphabet. We authored a dynamic program to compute precisely this - given a number of letters N from the alphabet, this program computes the minimum number of words it takes to cover all N letters.
Also see Letter Coverage page on the charlesreid1.com wiki.