Bacteria

Attempt done using scala framework.

To change starting input please update Input.txt

Usage

This is a normal sbt project. You can compile code with sbt compile, run it with sbt run, and sbt console will start a Scala 3 REPL.

For more information on the sbt-dotty plugin, see the scala3-example-project.

1 Introduction and Task

Build a simulation of a 2-dimensional grid petri dish of bacteria. While this exercise may appear similar to programming problems you have seen before please read carefully the instructions including test cases before attempting your solution. The bacteria in dish live and die by the following rules based on the bacteria surrounding it:

1. Any live bacteria cell with fewer than two live neighbours dies, as if caused by under-population
2. Any live bacteria cell with two or three live neighbours lives on to the next generation.
3. Any live bacteria cell with more than three live neighbours dies, as if by overcrowding.
4. Any dead bacteria cell with exactly three live neighbours becomes a live bacteria cell, as if by reproduction.

In table 1 if the starting step for the petri dish is the grid on the left the grid on the right would be the petri dish after one generation. You are free to choose any of the following programming language Java, Scala, JavaScript or TypeScript to implement your solution.

The the program will take from standard input a series of comma separated integer x,y pairs each on a new line that indicate the location of live bacteria cells. The input will be terminated with end. Output the results of your simulation to standard output consisting the of x,y pairs marking the locations of live bacteria cells after one generation has completed, terminate your output with end. The output of your program should be able to be used to feed into your program again to perform another “generation”.

Test Cases

Below is sample input and output to help you with your testing and confirm you are on the right track. Note that the sort order of the output from your program need not match the examples below as long as the correct points are included and the results are terminated with end.

Sample Input

1,2
2,2
3,2
1000000001,1000000002
1000000002,1000000002
1000000003,1000000002
end

Sample output

2,1
2,2
2,3
1000000002,1000000001
1000000002,1000000002
1000000002,1000000003
end