PlaySudoku.us
Expert · Puzzle #419
6
5
2
7
6
3
5
2
9
4
3
4
8
2
7
2
6
5
7
3
1
9
8
7
1
"We suffer more often in imagination than in reality." — Seneca
"We suffer more often in imagination than in reality." — Seneca
In combinatorics, the pattern formed by Sudoku clue cells is studied as a problem in 'hitting sets' and transversals.
In combinatorics, the pattern formed by Sudoku clue cells is studied as a problem in 'hitting sets' and transversals.