# Copyright 2010-2014 Google
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""This model implements a sudoku solver."""
from google.apputils import app
import gflags
from ortools.constraint_solver import pywrapcp
FLAGS = gflags.FLAGS
def main(unused_argv):
# Create the solver.
solver = pywrapcp.Solver('sudoku')
cell_size = 3
line_size = cell_size ** 2
line = range(0, line_size)
cell = range(0, cell_size)
initial_grid = [[0, 6, 0, 0, 5, 0, 0, 2, 0],
[0, 0, 0, 3, 0, 0, 0, 9, 0],
[7, 0, 0, 6, 0, 0, 0, 1, 0],
[0, 0, 6, 0, 3, 0, 4, 0, 0],
[0, 0, 4, 0, 7, 0, 1, 0, 0],
[0, 0, 5, 0, 9, 0, 8, 0, 0],
[0, 4, 0, 0, 0, 1, 0, 0, 6],
[0, 3, 0, 0, 0, 8, 0, 0, 0],
[0, 2, 0, 0, 4, 0, 0, 5, 0]]
grid = {}
for i in line:
for j in line:
grid[(i, j)] = solver.IntVar(1, line_size, 'grid %i %i' % (i, j))
# AllDifferent on rows.
for i in line:
solver.Add(solver.AllDifferent([grid[(i, j)] for j in line]))
# AllDifferent on columns.
for j in line:
solver.Add(solver.AllDifferent([grid[(i, j)] for i in line]))
# AllDifferent on cells.
for i in cell:
for j in cell:
one_cell = []
for di in cell:
for dj in cell:
one_cell.append(grid[(i * cell_size + di, j * cell_size + dj)])
solver.Add(solver.AllDifferent(one_cell))
# Initial values.
for i in line:
for j in line:
if initial_grid[i][j]:
solver.Add(grid[(i, j)] == initial_grid[i][j])
# Regroup all variables into a list.
all_vars = [grid[(i, j)] for i in line for j in line]
# Create search phases.
vars_phase = solver.Phase(all_vars,
solver.INT_VAR_SIMPLE,
solver.INT_VALUE_SIMPLE)
solution = solver.Assignment()
solution.Add(all_vars)
collector = solver.FirstSolutionCollector(solution)
# And solve.
solver.Solve(vars_phase, [collector])
if collector.SolutionCount() == 1:
for i in line:
print [int(collector.Value(0, grid[(i, j)])) for j in line]
if __name__ == '__main__':
app.run()