PlaySudoku.us
Hard · Puzzle #656
1
9
7
8
9
7
5
2
3
3
2
7
1
5
8
4
2
8
1
7
2
4
5
1
9
4
5
"Judge a man by his questions rather than by his answers." — Voltaire
"Judge a man by his questions rather than by his answers." — Voltaire
Network flow algorithms can solve special classes of Sudoku more efficiently than general backtracking.
Network flow algorithms can solve special classes of Sudoku more efficiently than general backtracking.