Thanks! I was just confused that it may have different solutions but in the sample tests I see only one. Actually I haven't run the code yet. It is my mistake.

(Java) My result for the first test is:

{1, 2, 3, 4, 5, 6, 7, 8, 9, 19, 29, 39, 49, 59, 69, 68, 67, 66, 65, 75, 85, 95, 94, 84, 74, 73, 72, 71, 70}

- 8 1 1 1 1 1 1 1 1 
- - - - - - - - - 1 
- - - - - - - - - 1 
- - - - - - - - - 1 
- - - - - - - - - 1 
- - - - - - - - - 1 
- - - - - 1 1 1 1 8 
8 1 1 1 1 1 - - - - 
- - - - 1 1 - - - - 
- - - - 1 8 - - - -

but it should be

{1, 2, 3, 4, 5, 6, 7, 8, 9, 19, 29, 39, 49, 59, 69, 79, 78, 77, 76, 75, 85, 95, 94, 93, 92, 91, 81, 71, 70}

- 8 1 1 1 1 1 1 1 1 
- - - - - - - - - 1 
- - - - - - - - - 1 
- - - - - - - - - 1 
- - - - - - - - - 1 
- - - - - - - - - 1 
- - - - - - - - - 8 
8 1 - - - 1 1 1 1 1 
- 1 - - - 1 - - - - 
- 1 1 1 1 8 - - - -

Both results meet the requirements, but my result isn't correct. Did I miss something?