This repository contains several hundred thousand Sudoku puzzles that were computer generated for use by the Sudoku Exchange web site.
The puzzles were generated using the QQWing Sudoku software, which ensure that each puzzle has a unique solution. The generated puzzles were then graded using Sukaku Explainer and sorted into four 'buckets':
| Filename | Difficulty Rating |
|---|---|
| easy.txt | < 1.5 |
| medium.txt | < 2.5 |
| hard.txt | < 5.0 |
| diabolical.txt | ≥ 5.0 |
Each text file has one puzzle per line, represented as three space-separated fields and a Unix-style line-ending, for a total of 100 bytes per record:
12 bytes of SHA1 hash of the digits string (for randomising order)
81 bytes of puzzle digits
4 bytes of rating (nn.n)
3 bytes of white-space (including the linefeed);
100 bytes total
The data set is dedicated to the public domain.