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| 1 | from constraint import * | |
| 2 | ||
| 3 | if __name__ == '__main__': | |
| 4 | problem = Problem(BacktrackingSolver()) | |
| 5 | ||
| 6 | num_queens = int(input()) | |
| 7 | ||
| 8 | queens = range(1, num_queens + 1) | |
| 9 | domain = [(i, j) for i in range(num_queens) for j in range(num_queens)] | |
| 10 | ||
| 11 | problem.addVariables(queens, domain) | |
| 12 | ||
| 13 | # ----------------Constraints begin here---------------- | |
| 14 | for queen1 in queens: | |
| 15 | for queen2 in queens: | |
| 16 | if queen1 < queen2: | |
| 17 | # Diagonal constraints | |
| 18 | problem.addConstraint(lambda q1, q2: (abs(q1[0] - q2[0]) != abs(q1[1] - q2[1])), (queen1, queen2)) | |
| 19 | # Row and column constraint | |
| 20 | problem.addConstraint(lambda q1, q2: q1[0] != q2[0] and q1[1] != q2[1], (queen1, queen2)) | |
| 21 | # ------------------------------------------------------ | |
| 22 | # If there are less than 7 queens, print only the number of solutions | |
| 23 | if num_queens < 7: | |
| 24 | print(len(problem.getSolutions())) | |
| 25 | else: | |
| 26 | print(problem.getSolution()) | |
| 27 |
