Analysis: 【Fun Question】By trying, we can find that changing two adjacent numbers together can result in the smallest change, such as: 89 can be changed to 01, 78 can be changed to 10. The number given in the question can be reduced to the smallest: 101010101
11. The number 123456789 is written on the blackboard. Choose two adjacent digits, if they are not 0, then each is reduced by 1 and their positions are swapped, for example: $123456789 \rightarrow 123436789 \rightarrow \cdots$. After performing such operations several times, the smallest number that can be obtained is $\qquad$ _.