Encode and Decode Strings

Design a way to turn a list of strings into one string and back. One program encodes the list and sends the string to another program, which decodes it into the same list of strings, in the same order.

Implement the class Codec:

• encode(strs) gets a list of strings strs and returns one string that holds all of them.
• decode(s) gets a string s made by encode and returns the original list of strings.

The strings can contain any printable character, including #, digits and spaces, and a string can be empty. So no single character can mark where one string ends and the next begins: that character could be inside a string too.

Each test is one list. It is encoded with one Codec object and decoded with another, as if the string were sent to another machine, so decode can use only the string it gets. The output is the decoded list. The starter code spells the method names the way your language does.

Example 1:

Input: strs = ["lint","code","love","you"]
Output: ["lint","code","love","you"]
Explanation: encode can return "4#lint4#code4#love3#you": for each string, its length,
a #, then the string itself. decode reads the 4 before the first #, takes the 4 characters
after it, "lint", and goes on from there.

Example 2:

Input: strs = ["3#a","","#"]
Output: ["3#a","","#"]
Explanation: The encoded string is "3#3#a0#1##". decode reads the length 3 up to the first #,
then takes exactly 3 characters, "3#a", although they hold a digit and a #.
Then "0#" gives the empty string, and "1##" gives "#".

Example 3:

Input: strs = []
Output: []
Explanation: An empty list encodes to the empty string "", which decodes to no strings at all.
A list with one empty string, [""], encodes to "0#" instead, so the two stay different.

Constraints:

• 0 <= strs.length <= 105
• 0 <= strs[i].length <= 200
• The total length of all the strings is at most 106.
• strs[i] consists of printable ASCII characters (codes 32 to 126): letters, digits, spaces and punctuation such as #.