96 lines
2.6 KiB
Python
96 lines
2.6 KiB
Python
# Copyright 2010-2013 Google
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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#
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"""This model implements a sudoku solver."""
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from google.apputils import app
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import gflags
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from constraint_solver import pywrapcp
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FLAGS = gflags.FLAGS
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def main(unused_argv):
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# Create the solver.
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solver = pywrapcp.Solver('sudoku')
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cell_size = 3
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line_size = cell_size ** 2
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line = range(0, line_size)
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cell = range(0, cell_size)
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initial_grid = [[0, 6, 0, 0, 5, 0, 0, 2, 0],
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[0, 0, 0, 3, 0, 0, 0, 9, 0],
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[7, 0, 0, 6, 0, 0, 0, 1, 0],
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[0, 0, 6, 0, 3, 0, 4, 0, 0],
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[0, 0, 4, 0, 7, 0, 1, 0, 0],
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[0, 0, 5, 0, 9, 0, 8, 0, 0],
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[0, 4, 0, 0, 0, 1, 0, 0, 6],
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[0, 3, 0, 0, 0, 8, 0, 0, 0],
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[0, 2, 0, 0, 4, 0, 0, 5, 0]]
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grid = {}
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for i in line:
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for j in line:
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grid[(i, j)] = solver.IntVar(1, line_size, 'grid %i %i' % (i, j))
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# AllDifferent on rows.
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for i in line:
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solver.Add(solver.AllDifferent([grid[(i, j)] for j in line]))
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# AllDifferent on columns.
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for j in line:
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solver.Add(solver.AllDifferent([grid[(i, j)] for i in line]))
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# AllDifferent on cells.
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for i in cell:
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for j in cell:
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one_cell = []
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for di in cell:
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for dj in cell:
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one_cell.append(grid[(i * cell_size + di, j * cell_size + dj)])
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solver.Add(solver.AllDifferent(one_cell))
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# Initial values.
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for i in line:
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for j in line:
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if initial_grid[i][j]:
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solver.Add(grid[(i, j)] == initial_grid[i][j])
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# Regroup all variables into a list.
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all_vars = [grid[(i, j)] for i in line for j in line]
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# Create search phases.
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vars_phase = solver.Phase(all_vars,
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solver.INT_VAR_SIMPLE,
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solver.INT_VALUE_SIMPLE)
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solution = solver.Assignment()
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solution.Add(all_vars)
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collector = solver.FirstSolutionCollector(solution)
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# And solve.
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solver.Solve(vars_phase, [collector])
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if collector.SolutionCount() == 1:
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for i in line:
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print [int(collector.Value(0, grid[(i, j)])) for j in line]
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if __name__ == '__main__':
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app.run()
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