PlaySudoku.us
Medium · Puzzle #930
2
6
9
7
1
1
2
8
3
8
4
1
9
2
2
5
3
8
7
1
4
2
7
2
5
6
9
3
7
8
6
1
6
9
3
1
"Judge a man by his questions rather than by his answers." — Voltaire
"Judge a man by his questions rather than by his answers." — Voltaire
The hardest Sudoku puzzles require techniques equivalent to propositional logic — the same foundation used in computer proofs.
The hardest Sudoku puzzles require techniques equivalent to propositional logic — the same foundation used in computer proofs.