Re: question about 10 millionth puzzle puzzle submission for
Yes, calcudoku.org will reject submissions if they have spaces. I tried this on my very first submission (a 10x10) with the same concerns, and it was rejected. I have solved and submitted a few puzzles 10x10 and up without spaces, and they passed without difficulty. On one occasion, I had an 11x11 where the solution had 1, 11, and 10 all in a row!
However, I think you do have a point. With 1 and 11,Someone could think they solved the puzzle with 11,1 instead of the correct solution of 1,11, but it would still be accepted. However unlikely this may be, it could still be an issue, so maybe spaces should be put between numbers.