PlaySudoku.us
Hard · Puzzle #669
3
7
8
8
1
7
2
3
3
2
1
6
5
5
6
9
2
7
1
9
2
1
2
7
4
4
5
6
3
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.
The average newspaper Sudoku takes about 20 minutes to solve for an experienced solver.
The average newspaper Sudoku takes about 20 minutes to solve for an experienced solver.