65 lines
2.1 KiB
C++
65 lines
2.1 KiB
C++
// Copyright 2010-2024 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.
|
|
|
|
#include <iostream>
|
|
#include <utility>
|
|
#include <vector>
|
|
|
|
#include "absl/log/check.h"
|
|
#include "absl/status/status.h"
|
|
#include "absl/strings/str_join.h"
|
|
#include "ortools/base/init_google.h"
|
|
#include "ortools/base/status_macros.h"
|
|
#include "ortools/graph/bfs.h"
|
|
|
|
namespace {
|
|
|
|
absl::Status Main() {
|
|
// The arcs of this directed graph are encoded as a list of pairs, where
|
|
// .first is the source and .second is the destination of each arc.
|
|
const std::vector<std::pair<int, int>> arcs = {
|
|
{0, 1}, {0, 2}, {1, 3}, {2, 4}, {2, 5}, {3, 0}, {3, 5}, {4, 5}};
|
|
const int num_nodes = 6;
|
|
|
|
// Transform the graph to an adjacency_list
|
|
std::vector<std::vector<int>> adjacency_list(num_nodes);
|
|
for (const auto& [start, end] : arcs) {
|
|
adjacency_list[start].push_back(end);
|
|
}
|
|
|
|
// Solve the shortest path problem from 0 to 5.
|
|
const int source = 0;
|
|
const int terminal = 5;
|
|
ASSIGN_OR_RETURN(
|
|
const std::vector<int> bfs_tree,
|
|
util::graph::GetBFSRootedTree(adjacency_list, num_nodes, source));
|
|
ASSIGN_OR_RETURN(const std::vector<int> shortest_path,
|
|
util::graph::GetBFSShortestPath(bfs_tree, terminal));
|
|
|
|
// Print to length of the path and then the nodes in the path.
|
|
std::cout << "Shortest path length (in arcs): " << shortest_path.size() - 1
|
|
<< std::endl;
|
|
std::cout << "Shortest path nodes: " << absl::StrJoin(shortest_path, ", ")
|
|
<< std::endl;
|
|
|
|
return absl::OkStatus();
|
|
}
|
|
|
|
} // namespace
|
|
|
|
int main(int argc, char** argv) {
|
|
InitGoogle(argv[0], &argc, &argv, true);
|
|
QCHECK_OK(Main());
|
|
return 0;
|
|
}
|