59 lines
1.8 KiB
C++
59 lines
1.8 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 <vector>
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#include "absl/log/check.h"
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#include "absl/status/status.h"
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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/base/status_macros.h"
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#include "ortools/graph/rooted_tree.h"
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namespace {
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absl::Status Main() {
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// Make an rooted tree on 5 nodes with root 2 and the parental args:
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// 0 -> 1
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// 1 -> 2
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// 2 is root
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// 3 -> 2
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// 4 -> 1
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ASSIGN_OR_RETURN(
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const operations_research::RootedTree<int> tree,
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operations_research::RootedTree<int>::Create(2, {1, 2, -1, 2, 1}));
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// Precompute this for LCA computations below.
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const std::vector<int> depths = tree.AllDepths();
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// Find the path between every pair of nodes in the tree.
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for (int s = 0; s < 5; ++s) {
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for (int t = 0; t < 5; ++t) {
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int lca = tree.LowestCommonAncestorByDepth(s, t, depths);
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const std::vector<int> path = tree.Path(s, t, lca);
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std::cout << s << " -> " << t << " [" << absl::StrJoin(path, ", ") << "]"
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<< std::endl;
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}
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}
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return absl::OkStatus();
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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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QCHECK_OK(Main());
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return 0;
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}
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