rust-sudoku-solver/puzzles/hard.csv

1	0	0	0	8	0	0	4	0	5
2	1	0	0	0	0	0	0	0	0
3	9	0	0	0	5	0	1	3	0
4	3	0	0	6	9	5	0	0	2
5	0	0	0	0	0	0	0	0	0
6	0	0	6	4	8	0	0	1	0
7	0	0	0	0	1	0	3	0	9
8	0	8	0	0	6	0	0	0	0
9	0	0	9	3	0	0	2	8	0