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62 lines
1.7 KiB
JavaScript
62 lines
1.7 KiB
JavaScript
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/**
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* File: graph_bfs.js
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* Created Time: 2023-02-21
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* Author: Zhuo Qinyue (1403450829@qq.com)
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*/
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const { GraphAdjList } = require('./graph_adjacency_list');
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const { Vertex } = require('../modules/Vertex');
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/* 廣度優先走訪 */
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// 使用鄰接表來表示圖，以便獲取指定頂點的所有鄰接頂點
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function graphBFS(graph, startVet) {
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// 頂點走訪序列
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const res = [];
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// 雜湊表，用於記錄已被訪問過的頂點
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const visited = new Set();
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visited.add(startVet);
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// 佇列用於實現 BFS
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const que = [startVet];
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// 以頂點 vet 為起點，迴圈直至訪問完所有頂點
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while (que.length) {
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const vet = que.shift(); // 佇列首頂點出隊
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res.push(vet); // 記錄訪問頂點
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// 走訪該頂點的所有鄰接頂點
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for (const adjVet of graph.adjList.get(vet) ?? []) {
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if (visited.has(adjVet)) {
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continue; // 跳過已被訪問的頂點
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}
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que.push(adjVet); // 只入列未訪問的頂點
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visited.add(adjVet); // 標記該頂點已被訪問
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}
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}
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// 返回頂點走訪序列
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return res;
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}
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/* Driver Code */
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/* 初始化無向圖 */
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const v = Vertex.valsToVets([0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);
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const 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[1], v[4]],
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[v[2], v[5]],
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[v[3], v[4]],
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[v[3], v[6]],
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[v[4], v[5]],
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[v[4], v[7]],
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[v[5], v[8]],
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[v[6], v[7]],
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[v[7], v[8]],
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];
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const graph = new GraphAdjList(edges);
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console.log('\n初始化後，圖為');
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graph.print();
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/* 廣度優先走訪 */
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const res = graphBFS(graph, v[0]);
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console.log('\n廣度優先走訪（BFS）頂點序列為');
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console.log(Vertex.vetsToVals(res));
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