N-Queens 问题求助

yanlizi

比较小白，请大家帮忙 感谢！
题目要求： 完成 addOrRemoveConstraints 和 placeMoves

board.py

1. class Board():
   
2. ##########################################
   
3. #### Constructor
   
4. ##########################################
   
5. def __init__(self, n):
   
6.         self.n = n
   
7.         self.spaces = n * n
   
8.         #indicates that all moves are possible at
   
9.         #the beginning
   
10.         self.constraints = {}
    
11.         for i in range(self.spaces):
    
12.                 self.constraints[i] = 0
    
13.         #holds the final places of the queens
    
14.         self.queenSpaces = []
    
15. 
    
16. ##########################################
    
17. #### Move Functions
    
18. ##########################################
    
19. #returns all moves that have 0 constraints on them
    
20. def getPossibleMoves(self):
    
21.         return [move for move in self.constraints if self.constraints[move] == 0]
    
22. def makeMove(self, space):
    
23. 
    
24. # add the queen
    
25.         self.queenSpaces.append(space)
    
26. # add the conflicts
    
27.         self.addOrRemoveConstraints(space)
    
28. 
    
29. def removeMove(self, space):
    
30. #remove the queen
    
31.         self.queenSpaces.remove(space)
    
32. #remove the dependent conflicts
    
33.         self.addOrRemoveConstraints(space, add=False)
    
34. 
    
35. ##########################################
    
36. #### Constraint Logic
    
37. ##########################################
    
38. #adds or removes constraints along the row, col, and diags of a move
    
39. def addOrRemoveConstraints(self, move, add=True):
    
40. # choosing whether to use add or remove function
    
41. if (add):
    
42.         mutationFx = self.addConstraint
    
43. else:
    
44.         mutationFx = self.removeConstraint
    
45. #TODO provide the logic to add or remove constraints from self.constraints
    
46. #YOUR CODE HERE
    
47. ##########################
    
48. 
    
49. #add 1 to the constraint counter for a particular space
    
50. def addConstraint(self, move):
    
51.         if not move == -1:
    
52.                 self.constraints[move] += 1
    
53. #remove 1 from the constraint counter for a particular space
    
54. def removeConstraint(self, move):
    
55.         if not move == -1:
    
56.                 self.constraints[move] -= 1
    
57. ##########################################
    
58. #### Utility Functions
    
59. ##########################################
    
60. #returns the corresponding space # based on 0-indexed row and column
    
61. #returns -1 if the space is not on the board
    
62. # e.g.
    
63. # rcToSpace(3,4) # the space at row 3, column 4
    
64. # > 28 # the corresponding space number given an 8x8 board
    
65. def rcToSpace(self, row, col):
    
66.         space = row * self.n + col
    
67.         if space >= self.spaces or space < 0:
    
68.                 return -1
    
69.         else:
    
70.                 return space
    
71. 
    
72. def print(self):
    
73.         for r in range(self.n):
    
74.                 row = ""
    
75.                 for c in range(self.n):
    
76.                         if(self.rcToSpace(r,c) in self.queenSpaces):
    
77.                                 row += "Q"
    
78.                         else:
    
79.                                 row += "-"
    
80.                         row += " "
    
81.         print(row)
    

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lab4.py

1. import board
   
2. # board to be manipulated below
   
3. b = board.Board(8)
   
4. #returns true if there exists a potential queen placement given the current board state
   
5. # and leaves b.queenspaces filled with the appropriate queen placements
   
6. #false if otherwise
   
7. def placeMoves():
   
8. 
   
9.   
   
10. 
    
11. #Hint 1: This should be recursively defined
    
12. #Hint 2: You should only need to use the following three functions from the board class
    
13. # - getPossibleMoves
    
14. # - makeMove
    
15. # - removeMove
    
16. 
    
17. if __name__ == "__main__":
    
18. placeMoves()
    
19. b.print()

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