FlowFreeSolver

Flow Free is a puzzle game that consists in pairing all colors and cover the entire board. Remember that no empty cells can be left, there can not be intersecting or non-finished paths.

This solution consists in writing all the restrictions as a SAT problem using Prolog, letting picosat (SAT solver) solve it and then retrieving the model to display the solution.

Input

The input structure is the following:

% size of the grid
size(9).
% initial points
c(blue,  9,1,2,2).
c(brown, 3,1,8,4).
c(red,   3,4,1,7).
c(cyan,  1,8,4,4).
c(green, 1,9,5,2).
c(yellow,7,7,7,9).
c(pink,  6,5,8,7).
c(violet,8,9,9,6).
c(orange,5,8,8,8).

Output

From the previous input, we would get the following output:

Usage

To use it, remember to change the input problem to the one desired ot solve, compile it using the Makefile and then run the executable to see the solution: 1- Change this line from flow.pl:

:-include(NAMEOFINPUT).

2- Compile and run it:

make flow
./flow

If you need to make a solution with more colors, look at the displaySol function because u'll need to define the code for more colors to show up in the terminal.

Requirements

In the case that you do not want to install any Prolog programming environment, like SWI-Prolog, you can use the Dockerfile:

docker build -t prolog . &&
docker run -it -d -v PATH_TO_REPOSITORY:/workspace prolog &&
docker exec -it name_of_container zsh
swipl