2025-01-10 11:35:44 +01:00
|
|
|
// Copyright 2010-2025 Google LLC
|
2021-01-14 10:48:19 +01:00
|
|
|
// 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.
|
|
|
|
|
|
|
|
|
|
// Magic sequence problem
|
|
|
|
|
//
|
|
|
|
|
// Compute a sequence of numbers such that the number of occurrences of i
|
|
|
|
|
// in the sequence is equal to the value of the ith number.
|
|
|
|
|
|
2021-04-23 14:55:51 +02:00
|
|
|
#include <cstdint>
|
|
|
|
|
#include <cstdlib>
|
2022-09-09 16:49:24 +02:00
|
|
|
#include <numeric>
|
|
|
|
|
#include <string>
|
|
|
|
|
#include <vector>
|
2021-01-14 10:48:19 +01:00
|
|
|
|
2025-02-25 16:03:40 +01:00
|
|
|
#include "absl/base/log_severity.h"
|
2021-01-14 10:48:19 +01:00
|
|
|
#include "absl/flags/flag.h"
|
2025-02-25 16:03:40 +01:00
|
|
|
#include "absl/log/check.h"
|
|
|
|
|
#include "absl/log/globals.h"
|
2025-03-04 21:10:09 +01:00
|
|
|
#include "absl/log/log.h"
|
2021-01-14 10:48:19 +01:00
|
|
|
#include "absl/strings/str_format.h"
|
2022-02-25 09:47:52 +01:00
|
|
|
#include "ortools/base/init_google.h"
|
2021-01-14 10:48:19 +01:00
|
|
|
#include "ortools/sat/cp_model.h"
|
|
|
|
|
|
|
|
|
|
ABSL_FLAG(int, size, 50, "Size of the problem.");
|
|
|
|
|
ABSL_FLAG(std::string, params, "log_search_progress:true,num_search_workers:8",
|
|
|
|
|
"Sat parameters.");
|
|
|
|
|
|
|
|
|
|
namespace operations_research {
|
|
|
|
|
namespace sat {
|
|
|
|
|
|
|
|
|
|
void MagicSequence(int size) {
|
|
|
|
|
CHECK_GE(size, 1);
|
|
|
|
|
CpModelBuilder cp_model;
|
|
|
|
|
|
|
|
|
|
std::vector<std::vector<BoolVar>> var_domains(size);
|
|
|
|
|
for (int i = 0; i < size; ++i) {
|
|
|
|
|
for (int j = 0; j < size; ++j) {
|
|
|
|
|
var_domains[i].push_back(cp_model.NewBoolVar());
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// Domain constraint on each position.
|
|
|
|
|
for (int i = 0; i < size; ++i) {
|
2021-12-08 16:29:40 +01:00
|
|
|
cp_model.AddEquality(LinearExpr::Sum(var_domains[i]), 1);
|
2021-01-14 10:48:19 +01:00
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// The number of variables equal to j shall be the value of vars[j].
|
2021-04-02 14:58:16 +02:00
|
|
|
std::vector<int64_t> values(size);
|
2021-01-14 10:48:19 +01:00
|
|
|
std::iota(values.begin(), values.end(), 0); // [0, 1, 2, .., size - 1]
|
|
|
|
|
std::vector<BoolVar> vars_equal_to_j;
|
|
|
|
|
|
|
|
|
|
for (int j = 0; j < size; ++j) {
|
|
|
|
|
vars_equal_to_j.clear();
|
|
|
|
|
for (int i = 0; i < size; ++i) {
|
|
|
|
|
vars_equal_to_j.push_back(var_domains[i][j]);
|
|
|
|
|
}
|
2022-01-04 19:35:22 +01:00
|
|
|
cp_model.AddEquality(LinearExpr::WeightedSum(var_domains[j], values),
|
2021-12-08 16:29:40 +01:00
|
|
|
LinearExpr::Sum(vars_equal_to_j));
|
2021-01-14 10:48:19 +01:00
|
|
|
}
|
|
|
|
|
|
|
|
|
|
const CpSolverResponse response =
|
|
|
|
|
SolveWithParameters(cp_model.Build(), absl::GetFlag(FLAGS_params));
|
|
|
|
|
|
|
|
|
|
if (response.status() == CpSolverStatus::OPTIMAL ||
|
|
|
|
|
response.status() == CpSolverStatus::FEASIBLE) {
|
|
|
|
|
std::string output = "[";
|
|
|
|
|
for (int i = 0; i < size; ++i) {
|
|
|
|
|
if (i != 0) {
|
|
|
|
|
output.append(", ");
|
|
|
|
|
}
|
|
|
|
|
for (int j = 0; j < size; ++j) {
|
|
|
|
|
if (SolutionBooleanValue(response, var_domains[i][j])) {
|
|
|
|
|
absl::StrAppendFormat(&output, "%d", j);
|
|
|
|
|
break;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
output.append("]");
|
|
|
|
|
LOG(INFO) << "Solution = " << output;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
} // namespace sat
|
|
|
|
|
} // namespace operations_research
|
|
|
|
|
|
|
|
|
|
int main(int argc, char** argv) {
|
2025-02-25 16:03:40 +01:00
|
|
|
absl::SetStderrThreshold(absl::LogSeverityAtLeast::kInfo);
|
2022-02-25 09:47:52 +01:00
|
|
|
InitGoogle(argv[0], &argc, &argv, true);
|
2021-01-14 10:48:19 +01:00
|
|
|
|
|
|
|
|
operations_research::sat::MagicSequence(absl::GetFlag(FLAGS_size));
|
|
|
|
|
return EXIT_SUCCESS;
|
|
|
|
|
}
|
