Problem 1:

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

Time:
real    0m0.371s
user    0m0.302s
sys     0m0.070s



Problem 2:

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

real    0m0.387s
user    0m0.325s
sys     0m0.062s


Problem 3:

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

real    0m0.401s
user    0m0.337s
sys     0m0.066s


Problem 4:

No solution

16 16 16 16 16 16 16 16 16
16 16 16 16 16 16 16 16 16
16 16 16 16 16 16 16 16 16
16 16 16 16 16 16 16 16 16
16 16 16 16 16 16 16 16 16
16 16 16 16 16 16 16 16 16
16 16 16 16 16 16 16 16 16
16 16 16 16 16 16 16 16 16
16 16 16 16 16 16 16 16 16

real    0m0.353s
user    0m0.298s
sys     0m0.056s
	
