52 lines
1.5 KiB
Python
52 lines
1.5 KiB
Python
# Copyright 2018 Gergo Rozner
|
|
# 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.
|
|
"""Solve the magic sequence problem with the CP-SAT solver."""
|
|
|
|
from __future__ import absolute_import
|
|
from __future__ import division
|
|
from __future__ import print_function
|
|
|
|
from ortools.sat.python import cp_model
|
|
|
|
|
|
def main():
|
|
n = 50
|
|
values = range(n)
|
|
|
|
model = cp_model.CpModel()
|
|
|
|
x = [model.NewIntVar(0, n, 'x%i' % i) for i in values]
|
|
|
|
for k in values:
|
|
tmp_array = []
|
|
for i in values:
|
|
tmp_var = model.NewBoolVar('')
|
|
model.Add(x[i] == k).OnlyEnforceIf(tmp_var)
|
|
model.Add(x[i] != k).OnlyEnforceIf(tmp_var.Not())
|
|
tmp_array.append(tmp_var)
|
|
model.Add(sum(tmp_array) == x[k])
|
|
|
|
# Redundant constraint.
|
|
model.Add(sum(x) == n)
|
|
|
|
solver = cp_model.CpSolver()
|
|
# No solution printer, this problem has only 1 solution.
|
|
solver.Solve(model)
|
|
print(solver.ResponseStats())
|
|
for k in values:
|
|
print('x[%i] = %i ' % (k, solver.Value(x[k])), end='')
|
|
print()
|
|
|
|
|
|
if __name__ == '__main__':
|
|
main() |