ortools-clone/ortools/sat/samples/optional_interval_sample_sat.cc

// 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.

// [START program]
#include <stdlib.h>

#include "absl/base/log_severity.h"
#include "absl/log/globals.h"
#include "ortools/base/init_google.h"
#include "ortools/base/logging.h"
#include "ortools/sat/cp_model.h"
#include "ortools/util/sorted_interval_list.h"

namespace operations_research {
namespace sat {

void OptionalIntervalSampleSat() {
  CpModelBuilder cp_model;
  const int kHorizon = 100;
  const Domain horizon(0, kHorizon);

  // An optional interval can be created from three affine expressions and a
  // BoolVar.
  const IntVar x = cp_model.NewIntVar(horizon).WithName("x");
  const IntVar y = cp_model.NewIntVar({2, 4}).WithName("y");
  const IntVar z = cp_model.NewIntVar(horizon).WithName("z");
  const BoolVar presence_var = cp_model.NewBoolVar().WithName("presence");

  const IntervalVar interval_var =
      cp_model.NewOptionalIntervalVar(x, y, z + 2, presence_var)
          .WithName("interval");
  LOG(INFO) << "start = " << interval_var.StartExpr()
            << ", size = " << interval_var.SizeExpr()
            << ", end = " << interval_var.EndExpr()
            << ", presence = " << interval_var.PresenceBoolVar()
            << ", interval_var = " << interval_var;

  // If the size is fixed, a simpler version uses the start expression and the
  // size.
  const IntervalVar fixed_size_interval_var =
      cp_model.NewOptionalFixedSizeIntervalVar(x, 10, presence_var)
          .WithName("fixed_size_interval_var");
  LOG(INFO) << "start = " << fixed_size_interval_var.StartExpr()
            << ", size = " << fixed_size_interval_var.SizeExpr()
            << ", end = " << fixed_size_interval_var.EndExpr()
            << ", presence = " << fixed_size_interval_var.PresenceBoolVar()
            << ", interval_var = " << fixed_size_interval_var;
}

}  // namespace sat
}  // namespace operations_research

int main(int argc, char* argv[]) {
  InitGoogle(argv[0], &argc, &argv, true);
  absl::SetStderrThreshold(absl::LogSeverityAtLeast::kInfo);
  operations_research::sat::OptionalIntervalSampleSat();
  return EXIT_SUCCESS;
}
// [END program]