71 lines
2.4 KiB
C++
71 lines
2.4 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 <iostream>
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#include <utility>
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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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namespace {
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// An edge in an undirected graph, the order of the endpoints does not matter.
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struct Edge {
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int endpoint1 = 0;
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int endpoint2 = 0;
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int length = 0;
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};
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} // namespace
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int main(int argc, char** argv) {
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InitGoogle(argv[0], &argc, &argv, true);
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// The input graph, encoded as a list of edges with distances.
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std::vector<Edge> edges = {
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{.endpoint1 = 0, .endpoint2 = 1, .length = 8},
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{.endpoint1 = 0, .endpoint2 = 2, .length = 1},
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{.endpoint1 = 1, .endpoint2 = 2, .length = 0},
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{.endpoint1 = 1, .endpoint2 = 3, .length = 1},
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{.endpoint1 = 1, .endpoint2 = 4, .length = 4},
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{.endpoint1 = 2, .endpoint2 = 4, .length = 5},
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{.endpoint1 = 3, .endpoint2 = 4, .length = 2},
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};
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// Transform the graph.
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std::vector<int> tails;
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std::vector<int> heads;
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std::vector<int> lengths;
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for (const Edge& edge : edges) {
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// The "forward" directed edge
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tails.push_back(edge.endpoint1);
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heads.push_back(edge.endpoint2);
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lengths.push_back(edge.length);
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// The "backward" directed edge
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tails.push_back(edge.endpoint2);
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heads.push_back(edge.endpoint1);
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lengths.push_back(edge.length);
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}
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// Solve the shortest path problem from 0 to 4.
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std::pair<int, std::vector<int>> result =
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operations_research::SimpleOneToOneShortestPath<int, int>(0, 4, tails,
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heads, lengths);
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// Print to length of the path and then the nodes in the path.
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std::cout << "Shortest path length: " << result.first << std::endl;
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std::cout << "Shortest path nodes: " << absl::StrJoin(result.second, ", ")
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<< std::endl;
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return 0;
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}
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