def backtrack_forward_mrv(assignment, board, domains,variable_assignment_count):
variable_assignment_count[0] = variable_assignment_count[0] + 1
# Tests for completion by adding assignments to board, then restores if not
# print " -------------------------"
for i in range(len(assignment)):
board.CurrentGameboard[assignment[i][0]][assignment[i][1]] = assignment[i][2]
# board.print_board()
if sudoku.iscomplete(board.CurrentGameboard):
return assignment
for i in range(len(assignment)):
board.CurrentGameboard[assignment[i][0]][assignment[i][1]] = 0
# Selects the variable to try values for
row, col = select_unassigned_variable_mrv(board,assignment, domains)
# Tries each possible value in the variable's domain
for val in sudoku.odv_forward(row,col,domains):
if sudoku.consistent(assignment, row, col, val,board.BoardSize): # If that value works, adds it to the assignment
assignment.append([row,col,val])
domains, changes, possible = sudoku.forward_check(row,col,val,domains,board,assignment) # Also, restricts the domain of other variables
if possible: # If no conflict is immediately detected, continues to the next variable to be assigned
result = backtrack_forward_mrv(assignment,board,domains, variable_assignment_count)
if result != None: # If that was successful, return its result
return result
if assignment: # Otherwise, remove the assignment and restore the domains
assignment.pop()
domains = sudoku.reverse_forward(changes,domains)
return None # If none of them work, return none
def backtrack(assignment, board, variable_assignment_count): variable_assignment_count[0] = variable_assignment_count[0] + 1 for i in range(len(assignment)): board.CurrentGameboard[assignment[i][0]][assignment[i][1]] = assignment[i][2] if sudoku.iscomplete(board.CurrentGameboard): return assignment for i in range(len(assignment)): board.CurrentGameboard[assignment[i][0]][assignment[i][1]] = 0 row, col = sudoku.select_unassigned_variable(board,assignment) for val in order_domain_values(row, col, assignment, board): if sudoku.consistent(assignment, row, col, val,board.BoardSize): assignment.append([row,col,val]) result = backtrack(assignment, board, variable_assignment_count) if result != None: return result if assignment: assignment.pop() return None