Goban Technical Test

This repository contains the same technical test implemented in two languages: Python and Java.

Goal

Implement a method that determines whether the stone at position x, y on a goban (Go board) is taken (i.e. the entire shape it belongs to has no liberties).

Vocabulary

• Goban: the board on which stones are placed.
• Shape: one or more orthogonally adjacent stones (up, down, left, right) of the same color. Diagonals do not count.
• Liberty: an empty point orthogonally adjacent to any stone in a shape.

Rules Recap

1. The goban size is arbitrary (handled by the provided data structure).
2. Two players: Black (#) and White (o).
3. Stones are placed one per turn; positions outside the provided grid are considered OUT.
4. A shape is taken when it has no liberties.

Task

Write the function that returns whether the stone at (x, y) is taken:

• Python: implement Goban.is_taken(self, x, y) in python/goban.py.
• Java: implement Goban.isTaken(int x, int y) in java/src/main/java/com/example/goban/Goban.java.

Return True / true only if the stone exists at (x, y) and the entire connected shape of that color has zero liberties.

You may add helper functions / parameters if needed while keeping clear, idiomatic code.

Make use of the provided status accessors:

• Python: get_status(x, y) returns Status.BLACK, Status.WHITE, Status.EMPTY, or Status.OUT.
• Java: getStatus(x, y) returns the equivalent Status enum values.

The return values are:

• Status.BLACK: when the stone at position x, y is black
• Status.WHITE: when the stone at the x position, y is white
• Status.EMPTY: when there is no stone at position x, y
• Status.OUT: when the position x, y is out of the goban

Examples

# = black
o = white
. = empty

.#.
#o#    <= o is taken: no adjacent empty points
.#.

...
#o#    <= o is not taken: liberty above
.#.

o#    <= o is taken: top and left are OUT (not liberties)
#.

oo.
##o    <= black shape (#) is taken: no liberties
o#o
.o.

oo.
##.    <= black shape (#) is not taken: liberty at x=2, y=1 (0,0 top-left)
o#o
.o.

Running Tests

Python

From repository root:

git clone https://github.com/lumapps/test-goban.git
cd test-goban/python
python3 -m venv venv
source venv/bin/activate
pip install -r requirements.txt
PYTHONPATH=. pytest test_goban.py

(Tests use direct module import goban; running inside python/ ensures it is on the module search path.)

Java

From repository root:

git clone https://github.com/lumapps/test-goban.git
cd test-goban/java
./gradlew test

Files of Interest

• Python implementation: python/goban.py
• Python tests: python/test_goban.py
• Java implementation: java/src/main/java/com/example/goban/Goban.java
• Java tests: java/src/test/java/com/example/goban/GobanTest.java

Focus only on implementing the capture logic; no additional features required.