单点时限: 2.0 sec
内存限制: 512 MB
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