20 18 answers to the questions of the 16th Shaoxing children's Olympic informatics preliminaries (1 2)
Question 1: A number is C2 1 = 2, that is, choose one of the two numbers. These two digits are/kloc-0 of C2/× kloc-0 of C2/= 2× 2 = 4. These three numbers are C2'1× C2'1× C2'1= 2× 2× 2 = 8. By analogy, there are 16 four digits and 32 five digits. The number 10 is the fourth of the three digits. According to the above, it should be 688. The 29th position, namely 15, is 8886.