Picross/Nonogram Solver

Little for-fun project. Expect spaghetti code.

Instructions:

• import picross_solver.solver.Solver
• Create a Solver object from column and row constraints (see example below)
• run the Solver instance's solve method.
• Print out the Solver instance to see the constraints and solved grid.

If you want to work with the result, its a numpy array at Solver.current_state.field_arr. Note that its transposed because it made more sense to me to use (x, y) instead of (y, x).

If the nonogram is not solvable by looking at individual rows/columns, it will not work.

Examples

An example for Pictopix's 1st level:

from picross_solver import Solver

column_constraints = [[0], [1,1], [1,1], [5], [0]]
row_constraints = [[3], [1], [3], [1], [1]]

mySolver = Solver.from_constraints(column_constraints, row_constraints)
mySolver.solve()

# To see constraints and solved grid
print(solver.current_state)

And a bigger example, Pictopix's 83rd level (page 6, 8th, 15x15 "Flora" theme):

from picross_solver import Solver

column_constraints = [[2], [2,3], [4,2], [7,2], [4,5], [4,4,2], [4,7], [2,6], [2,5], [4,2,2], [4,8], [4,2,4], [6,3], [4], [2]]
row_constraints = [[0],[2,2],[4,4],[4,4],[5,5],[2,4,3],[5,1,5],[6,5],[6,2],[5,2],[2,3,3],[2,4,3],[2,8],[2,5],[2]]

mySolver = Solver.from_constraints(column_constraints, row_constraints)
mySolver.solve()

# To see constraints and solved grid
print(solver)

Notes

By default uses an algorithm, Solver.SPINMEM where the possibilities for each "bar" is stored in the Solver state, and filters according to those. The alternate algorithm, Solver.SPIN does the same but recalculates all of the bar possibilities given the constraints on each iteration, so its quite a bit slower. Just use Solver.SPINMEM if you dont mind the spaghetti code, and give Solver.SPIN a try if the other one fails for any reason.

Other

Thanks to my friend Chalbus for pushing me to finish this. Please check them out on twitter. :D