84 lines
2.5 KiB
Python
Executable File
84 lines
2.5 KiB
Python
Executable File
#!/usr/bin/env python3
|
|
# Copyright 2010-2025 Google LLC
|
|
# 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 ortools.sat.python import cp_model
|
|
|
|
|
|
def solve_sudoku() -> None:
|
|
"""Solves the sudoku problem with the CP-SAT solver."""
|
|
# Create the model.
|
|
model = cp_model.CpModel()
|
|
|
|
cell_size = 3
|
|
line_size = cell_size**2
|
|
line = list(range(0, line_size))
|
|
cell = list(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)] = model.new_int_var(1, line_size, "grid %i %i" % (i, j))
|
|
|
|
# AllDifferent on rows.
|
|
for i in line:
|
|
model.add_all_different(grid[(i, j)] for j in line)
|
|
|
|
# AllDifferent on columns.
|
|
for j in line:
|
|
model.add_all_different(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)])
|
|
|
|
model.add_all_different(one_cell)
|
|
|
|
# Initial values.
|
|
for i in line:
|
|
for j in line:
|
|
if initial_grid[i][j]:
|
|
model.add(grid[(i, j)] == initial_grid[i][j])
|
|
|
|
model.export_to_file('/tmp/sudoku_sat.pb.txt')
|
|
|
|
# Solves and prints out the solution.
|
|
solver = cp_model.CpSolver()
|
|
solver.parameters.num_workers = 1
|
|
solver.parameters.log_search_progress = True
|
|
status = solver.solve(model)
|
|
if status == cp_model.OPTIMAL:
|
|
for i in line:
|
|
print([int(solver.value(grid[(i, j)])) for j in line])
|
|
|
|
|
|
solve_sudoku()
|