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59 lines
1.4 KiB
Dart
59 lines
1.4 KiB
Dart
/**
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* File: graph_dfs.dart
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* Created Time: 2023-05-15
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* Author: liuyuxin (gvenusleo@gmail.com)
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*/
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import '../utils/vertex.dart';
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import 'graph_adjacency_list.dart';
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/* 深度優先走訪輔助函式 */
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void dfs(
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GraphAdjList graph,
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Set<Vertex> visited,
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List<Vertex> res,
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Vertex vet,
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) {
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res.add(vet); // 記錄訪問頂點
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visited.add(vet); // 標記該頂點已被訪問
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// 走訪該頂點的所有鄰接頂點
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for (Vertex adjVet in graph.adjList[vet]!) {
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if (visited.contains(adjVet)) {
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continue; // 跳過已被訪問的頂點
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}
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// 遞迴訪問鄰接頂點
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dfs(graph, visited, res, adjVet);
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}
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}
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/* 深度優先走訪 */
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List<Vertex> graphDFS(GraphAdjList graph, Vertex startVet) {
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// 頂點走訪序列
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List<Vertex> res = [];
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// 雜湊集合，用於記錄已被訪問過的頂點
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Set<Vertex> visited = {};
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dfs(graph, visited, res, startVet);
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return res;
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}
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/* Driver Code */
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void main() {
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/* 初始化無向圖 */
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List<Vertex> v = Vertex.valsToVets([0, 1, 2, 3, 4, 5, 6]);
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List<List<Vertex>> edges = [
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[v[0], v[1]],
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[v[0], v[3]],
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[v[1], v[2]],
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[v[2], v[5]],
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[v[4], v[5]],
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[v[5], v[6]],
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];
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GraphAdjList graph = GraphAdjList(edges);
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print("\n初始化後，圖為");
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graph.printAdjList();
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/* 深度優先走訪 */
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List<Vertex> res = graphDFS(graph, v[0]);
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print("\n深度優先走訪（DFS）頂點序列為");
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print(Vertex.vetsToVals(res));
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}
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