How to Solve: Help the Bookseller Challenge in Python
A bookseller has lots of books classified in 26 categories labeled A, B, … Z. Each book has a code c of 3, 4, 5 or more characters. The 1st character of a code is a capital letter which defines the book category.
In the bookseller’s stocklist each code c is followed by a space and by a positive integer n (int n >= 0) which indicates the quantity of books of this code in stock.
For example an extract of a stocklist could be:
L = {"ABART 20", "CDXEF 50", "BKWRK 25", "BTSQZ 89", "DRTYM 60"}.
or
L = ["ABART 20", "CDXEF 50", "BKWRK 25", "BTSQZ 89", "DRTYM 60"] or ....
You will be given a stocklist (e.g. : L) and a list of categories in capital letters e.g :
M = {"A", "B", "C", "W"}
or
M = ["A", "B", "C", "W"] or ...
and your task is to find all the books of L with codes belonging to each category of M and to sum their quantity according to each category.
For the lists L and M of example you have to return the string:
(A : 20)  (B : 114)  (C : 50)  (W : 0)
where A, B, C, W are the categories, 20 is the sum of the unique book of category A, 114 the sum corresponding to “BKWRK” and “BTSQZ”, 50 corresponding to “CDXEF” and 0 to category ‘W’ since there are no code beginning with W.
If L
or M
are empty return string is “”.
Notes:
 In the result codes and their values are in the same order as in M.
 See “Samples Tests” for the return.
The Solution in Python
Option 1


Option 2
Option 3
Test cases to validate the solution

