Encode and Decode Strings

Design a way to pack a list of strings into one string and unpack it again. Implement two functions:

• encode(strs) takes a list of strings and returns a single string.
• decode(data) takes a string produced by your encode and returns the original list.

You choose the format. The only requirement is that decode(encode(strs)) gives back a list equal to strs for every valid input: the same strings, in the same order, with the same count. Strings may be empty and may contain any ASCII character, including ones you might be tempted to use as separators such as #, ,, digits, spaces and newlines. Do not lean on a built-in serializer (json, pickle, repr/eval); the point is to design the format yourself.

Each test calls your encode on a list, passes the result to your decode, and compares what comes back with the original list. The examples below show that round-trip result.