You've intercepted a series of transmissions encrypted using an interesting and stupid method, which you have managed to decipher. The messages contain only ...

You're interested in figuring out the number of case-insensitive unique characters in some string. This sounds simple and easily-automated, so you just decide ...

For two integers a and c, we define a and a third integer b to be almost factors of c by choosing the minimal b that minimizes |ab-c|. Your task will be to ...