Solver for n-queens problem which strips solutions containing colinear
triplets. Written in Java utilizing the Gradle build system. Utilizes
Lombok for getter annotations and Apache Commons CombinatoricsUtils for
iterating over queen positions in solution boards to find colinear
triplets.
Every n-queens tutorial I read on the internet covered the recursive
solution, so I decided to build a solution that was non-recursive for
the added challenge. It makes use of a flag to determine whether it
should be backtracking or adding new queens.
It also keeps track of the current state of the board by recording all
occupied rows, columns and diagonals (both northwest-to-southeast and
northeast-to-southwest, dubbed "main" and "anti" internally after the
matrix math terms). This simplifies the test for whether a square
would constitute a valid position to place a new queen to a single
conditional statement.
You can buld and run on the command-line with gradle by issuing a statement of the form:
```./gradlew run --args=N````
where N is an integer representing the size of the board you'd like to test.
./gradlew test [-i]
Use the -i flag to display logs to stdout.