Puzzle

Puzzle 7 (Evil)

Non-Heuristic

Heuristic

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

Sudoku seems not to have been solved as it does not display results.

[3,4,5]	6	[2,5,7]	[2,3,9]	[2,3,5,9]	8	1	[2,3,5,7]	[2,3,4,5,7]
8	9	1	7	[2,3,5]	[2,4,5,6]	[2,3,4,5,6]	[2,3,5]	[2,3,4,5]
[3,4,5]	[3,4,5,7]	[2,5,7]	[1,2,3,6]	[1,2,3,5]	[2,4,5,6]	[2,3,4,5,6,8]	[2,3,5,7,8]	9
9	8	4	5	6	[2,7]	[2,3]	[2,3,7]	1
6	2	3	[1,8,9]	[1,7,8,9]	[7,9]	[5,9]	4	[5,7]
1	[5,7]	[5,7]	[2,9]	4	3	[2,5,9]	6	8
7	1	9	[2,3,6,8]	[2,3,5,8]	[2,5,6]	[2,3,4,5,8]	[2,3,5,8]	[2,3,4,5]
[2,3,4,5]	[3,4,5]	8	[2,3]	[2,3,5]	1	7	9	6
[2,3,5]	[3,5]	6	4	[2,3,5,7,8,9]	[2,5,7,9]	[2,3,5,8]	1	[2,3,5]

applied square rule

applied triples rule

true ?

(456 ms) yes

Sudoku is solved using backtracking.

4 6 5 2 9 8 1 3 7

8 9 1 7 3 5 6 2 4

3 7 2 6 1 4 5 8 9

9 8 4 5 6 2 3 7 1

6 2 3 1 8 7 9 4 5

1 5 7 9 4 3 2 6 8

7 1 9 8 2 6 4 5 3

2 4 8 3 5 1 7 9 6

5 3 6 4 7 9 8 1 2

For this puzzle it seems like there is a flaw in Non-Heuristic pairs rule. Consider row 6 in which boxes 2 and 3 in that row contain pairs [5,7]. Accordingly, these values should be removed from other box's candidate lists located in the same row as these boxes, which would then make the puzzle more likely to be solved.