main.py

from csp_representation import CSP
from csp_solver import *

def create_map_coloring_csp():
    """Instantiate a CSP representing the map coloring problem from the
    textbook. This can be useful for testing your CSP solver as you
    develop your code.
    """
    csp = CSP()
    states = [ 'WA', 'NT', 'Q', 'NSW', 'V', 'SA', 'T' ]
    edges = { 'SA': [ 'WA', 'NT', 'Q', 'NSW', 'V' ], 'NT': [ 'WA', 'Q' ], 'NSW': [ 'Q', 'V' ] }
    colors = [ 'red', 'green', 'blue' ]
    for state in states:
        csp.add_variable(state, colors)
    for state, other_states in edges.items():
        for other_state in other_states:
            csp.add_constraint_one_way(state, other_state, lambda i, j: i != j)
            csp.add_constraint_one_way(other_state, state, lambda i, j: i != j)
    return csp



def create_sudoku_csp(filename):
    """Instantiate a CSP representing the Sudoku board found in the text
    file named 'filename' in the current directory.
    """
    csp = CSP()
    path = f"boards/{filename}"
    board = open(path, 'r')
    board = list(map(lambda x: x.strip("\n"), board))

    for row in range(9):
        for col in range(9):
            if board[row][col] == '0':
                csp.add_variable('%d-%d' % (row, col), map(str, range(1, 10)))
            else:
                csp.add_variable('%d-%d' % (row, col), [ board[row][col] ])

    for row in range(9):
        csp.add_all_different_constraint([ '%d-%d' % (row, col) for col in range(9) ])
    for col in range(9):
        csp.add_all_different_constraint([ '%d-%d' % (row, col) for row in range(9) ])
    for box_row in range(3):
        for box_col in range(3):
            cells = []
            for row in range(box_row * 3, (box_row + 1) * 3):
                for col in range(box_col * 3, (box_col + 1) * 3):
                    cells.append('%d-%d' % (row, col))
            csp.add_all_different_constraint(cells)

    return csp

print("Very Hard Board")
sdk_csp = create_sudoku_csp("veryhard.txt")
solution = backtracking_search(sdk_csp)

def print_sudoku_solution(solution):
    """Convert the representation of a Sudoku solution as returned from
    the method CSP.backtracking_search(), into a human readable
    representation.
    """

    counter = 0
    counter_two = 0
    counter_three = 0
    row = ""
    for key, value in solution.items():

        row += str(value[0]) + " "
        counter += 1
        counter_two += 1
        if counter_two % 3 == 0:
            row += "|"
            counter_two = 0
        if counter % 9 == 0:
            counter_three += 1
            print(row)
            if counter_three % 3 == 0:
                counter_three = 0
                print("---------------------")
            row = ""


print_sudoku_solution(solution)