Loading puzzle from 'sample00.txt' ...
 -  -  4  -  -  -  9  -  - 
 -  7  6  1  -  -  -  -  - 
 -  -  -  -  7  -  1  2  - 
 9  -  8  4  -  -  -  -  - 
 3  6  -  -  1  -  -  -  - 
 5  -  -  -  -  7  -  3  8 
 -  -  -  3  -  -  -  7  9 
 6  8  -  -  -  1  -  -  2 
 -  -  -  -  5  -  6  -  1 
There are 53 unknown positions to start.
[2,0] = 8 (only digit possible for [2,0])
[1,0] = 2 (only digit possible for [1,0])
[0,0] = 1 (only digit possible for [0,0])
[6,0] = 4 (only digit possible for [6,0])
[8,0] = 7 (only digit possible for [8,0])
[3,7] = 1 (only place to put a '1' in box 5)
[3,1] = 2 (only digit possible for [3,1])
[4,2] = 7 (only digit possible for [4,2])
[5,2] = 1 (only digit possible for [5,2])
[5,1] = 4 (only digit possible for [5,1])
[5,6] = 2 (only digit possible for [5,6])
[6,1] = 1 (only place to put a '1' in col 1)
[7,6] = 3 (only place to put a '3' in box 8)
[3,8] = 6 (only place to put a '6' in box 5)
[3,4] = 3 (only digit possible for [3,4])
[3,5] = 5 (only digit possible for [3,5])
[3,6] = 7 (only digit possible for [3,6])
[0,7] = 6 (only place to put a '6' in box 2)
[0,8] = 7 (only place to put a '7' in row 0)
[7,3] = 7 (only place to put a '7' in col 3)
[4,7] = 9 (only place to put a '9' in box 5)
excluding 4 from [1,7] (needed for box 8)
excluding 5 from [2,2] (needed for box 6)
excluding 8 from [1,4] (needed for box 2)
excluding 8 from [1,5] (needed for box 2)
excluding 9 from [2,3] (needed for box 0)
excluding 9 from [2,5] (needed for box 0)
Starting trial and error processing with this configuration:
 1  -  4  -  -  -  9  6  7 
 2  7  6  1  -  -  -  -  - 
 8  -  -  -  7  -  1  2  - 
 9  2  8  4  3  5  7  1  6 
 3  6  7  -  1  -  -  9  - 
 5  4  1  -  -  7  2  3  8 
 4  1  -  3  -  -  -  7  9 
 6  8  -  7  -  1  3  -  2 
 7  -  -  -  5  -  6  -  1 
Trying [0][1] = 3 ...
[2,2] = 9 (only digit possible for [2,2])
[2,1] = 5 (only digit possible for [2,1])
[2,3] = 6 (only digit possible for [2,3])
[5,3] = 9 (only digit possible for [5,3])
[5,4] = 6 (only digit possible for [5,4])
[7,2] = 5 (only digit possible for [7,2])
[6,2] = 2 (only digit possible for [6,2])
[6,4] = 8 (only digit possible for [6,4])
[0,4] = 2 (only digit possible for [0,4])
[0,5] = 8 (only digit possible for [0,5])
[0,3] = 5 (only digit possible for [0,3])
[4,5] = 2 (only digit possible for [4,5])
[4,3] = 8 (only digit possible for [4,3])
[6,5] = 6 (only digit possible for [6,5])
[6,6] = 5 (only digit possible for [6,6])
[4,6] = 4 (only digit possible for [4,6])
[1,6] = 8 (only digit possible for [1,6])
[1,7] = 5 (only digit possible for [1,7])
[4,8] = 5 (only digit possible for [4,8])
[7,7] = 4 (only digit possible for [7,7])
[7,4] = 9 (only digit possible for [7,4])
[1,4] = 4 (only digit possible for [1,4])
[1,8] = 3 (only digit possible for [1,8])
[1,5] = 9 (only digit possible for [1,5])
[2,5] = 3 (only digit possible for [2,5])
[2,8] = 4 (only digit possible for [2,8])
[8,1] = 9 (only digit possible for [8,1])
[8,2] = 3 (only digit possible for [8,2])
[8,3] = 2 (only digit possible for [8,3])
[8,5] = 4 (only digit possible for [8,5])
[8,7] = 8 (only digit possible for [8,7])
 1  3  4  5  2  8  9  6  7 
 2  7  6  1  4  9  8  5  3 
 8  5  9  6  7  3  1  2  4 
 9  2  8  4  3  5  7  1  6 
 3  6  7  8  1  2  4  9  5 
 5  4  1  9  6  7  2  3  8 
 4  1  2  3  8  6  5  7  9 
 6  8  5  7  9  1  3  4  2 
 7  9  3  2  5  4  6  8  1