Kingdom

This is a Python implementation of the Kingdom programming problem.

In Kingdom, there exists a field containing 3 simple actors—mountains, open fields, and armies. The mountains serve as the delimiter of the open fields. The open fields serve as objects to be captured by an army—a single army, armies of the same kingdom, or armies from different kingdoms.

The problem is to process a string grid containing the following various symbols and their representations:

• #: mountain
• .: field
• a-z: army

For this particular problem, the handling of field neighbors is through the four cardinal directions—west, north, east, and south. The script accomplishes the following tasks:

• Return all the fields occupied by at least one army.
• Return the number of armies of the different kingdoms.
• Return the number of contested fields (those that contain at least 2 armies from different kingdoms).

Table of contents

• Usage
  • REPL
  • File input
    • File output
• Remarks

Usage

REPL

Run the following commands in your terminal:

$ git clone https://github.com/zhaqenl/kingdom ~/python/kingdom
$ cd ~/python/kingdom
$ python

Once inside the interactive interpreter, import the following modules:

>>> import core
>>> import input_data

The input_data module contains sample data which the core module requires. The core module on the other hand contains the KingdomSolver class where its __init__ method require a string_grid argument:

>>> simple_solver = core.KingdomSolver(input_data.simple_grid)

After the instance creation, we call its contested() instance method:

>>> simple_solver.contested()

The result of the above invokation is a tuple whose first element is the total number of fields being contested, while the second element is a dictionary containing contested fields as the dictionary keys, and the respective contesting armies as the dictionary values:

>>> simple_solver.contested()
(1, {frozenset([(1, 3), (2, 3), (3, 3), (2, 2), (3, 0), (3, 1), (2, 1)]): set(['e', 'f'])})

To return the tally of the armies from the different kingdoms, invoke the map_army_count() instance method:

>>> simple_solver.map_army_count()
[('e', 1), ('f', 2)]

File input

If you prefer a file as the input of the script, you could create a file whose first line indicates the total number of cases, followed by the row quantity then the column quantity of the first case, then the string grid itself. See dummy_input.txt for an example structure.

After creating the .txt file, run the script in the following manner to get the tally of the armies from the different kingdoms and the number of fields being contested by these armies:

$ python kingdom.py dummy_input.txt
Case 1:
e 1
f 2
contested 1
Case 2:
a 1
e 1
f 2
g 1
contested 2
Case 3:
a 1
b 1
c 2
d 1
e 1
x 3
contested 1
Case 4:
a 2
b 2
c 3
d 2
e 3
x 3
contested 3

File output

If you want to save the output of running the script on an input file, redirect its output stream:

$ python kingdom.py dummy_input.txt > dummy_output.txt