64 lines
2.2 KiB
C++
64 lines
2.2 KiB
C++
// Copyright 2010-2025 Google LLC
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include <cstdint>
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#include <iostream>
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#include <limits>
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#include <vector>
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#include "absl/strings/str_join.h"
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#include "ortools/base/init_google.h"
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#include "ortools/graph/bounded_dijkstra.h"
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#include "ortools/graph/graph.h"
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int main(int argc, char** argv) {
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InitGoogle(argv[0], &argc, &argv, true);
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// Create the graph
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util::StaticGraph<> graph;
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std::vector<int> weights;
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graph.AddArc(0, 1);
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weights.push_back(2);
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graph.AddArc(1, 2);
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weights.push_back(4);
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graph.AddArc(1, 3);
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weights.push_back(0);
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graph.AddArc(2, 3);
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weights.push_back(6);
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graph.AddArc(3, 0);
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weights.push_back(8);
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graph.AddArc(4, 2);
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weights.push_back(1);
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// Static graph reorders the arcs at Build() time, use permutation to get
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// from the old ordering to the new one.
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std::vector<int32_t> permutation;
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graph.Build(&permutation);
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util::Permute(permutation, &weights);
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// Compute the shortest path to each reachable node.
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operations_research::BoundedDijkstraWrapper<util::StaticGraph<>, int>
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dijkstra(&graph, &weights);
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const std::vector<int> reachable_from_zero = dijkstra.RunBoundedDijkstra(
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/*source_node=*/0, /*distance_limit=*/std::numeric_limits<int>::max());
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// Print paths from zero to the reachable nodes ordered by distance.
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for (const int dest : reachable_from_zero) {
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const int distance = dijkstra.distances()[dest];
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const std::vector<int32_t> path = dijkstra.NodePathTo(dest);
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std::cout << "Distance to " << dest << ": " << distance << std::endl;
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std::cout << "Path to " << dest << ": " << absl::StrJoin(path, ", ")
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<< std::endl;
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}
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}
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