Enter line 1: Enter line 2: Enter line 3: Enter line 4: Enter line 5: Enter line 6: Enter line 7: Enter line 8: Enter line 9: 

Input puzzle:

300910750
100570009
009000000
020740090
900000003
010069020
000000300
700085006
098034002

Number of attempts: 4930
Number of backtracks: 594

Solution:

382 | 916 | 754
146 | 578 | 239
579 | 423 | 168
---------------
823 | 741 | 695
967 | 852 | 413
415 | 369 | 827
---------------
254 | 697 | 381
731 | 285 | 946
698 | 134 | 572