If there is any secret in this problem? I have just reading all data in one-dimensional massive and fill it while there is any extra box.
 10 boxes must be lay on this set:
 1 1 1 1 2 2 2 3 3 3 3 3 and 10=>
 2 2 2 2 2 2 2 3 3 3 3 3 and 6=>
 3 3 3 3 3 3 2 3 3 3 3 3 and 0
 Do I must write "2" or "3" ?
 Can somebody explain my mistake or give me a hint, please?

You must write the minimum height. In your case this is 2