PlaySudoku.us
Hard · Puzzle #881
9
7
6
8
3
5
4
3
2
7
6
9
3
5
2
2
3
1
9
2
5
7
3
4
8
7
1
3
9
Donald Knuth's "Algorithm X" with dancing links solves exact cover problems — of which Sudoku is a special case.
Donald Knuth's "Algorithm X" with dancing links solves exact cover problems — of which Sudoku is a special case.
"Begin at once to live, and count each separate day as a separate life." — Seneca
"Begin at once to live, and count each separate day as a separate life." — Seneca