PlaySudoku.us
Medium · Puzzle #677
6
5
1
7
2
9
6
3
1
5
7
2
5
4
2
5
6
1
6
3
2
9
9
6
3
8
5
7
5
6
1
"Play the opening like a book, the middlegame like a magician, and the endgame like a machine." — Rudolf Spielmann
"Play the opening like a book, the middlegame like a magician, and the endgame like a machine." — Rudolf Spielmann
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.