EOJ-自适应编程学习平台

Write a program that expands shorthand notations like a-z in the string $s_1$ into the equivalent complete list abc...xyz in $s_2$. Allow for letters of either case and digits, and be prepared to handle cases like a-b-c and a-z0-9 and -a-z. Arrange that a leading or trailing - is taken literally.

You can assume that the input string does not exceed $10$, only contains letters of both cases, digits, and -.

a-z

abcdefghijklmnopqrstuvwxyz

a-b-c

abc

a-z0-9

abcdefghijklmnopqrstuvwxyz0123456789

-a-z

-abcdefghijklmnopqrstuvwxyz

abcA-C

abcABC