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14c314c08c
* Retranslate the complete English edition from Simplified Chinese * Polish three English explanations after reader-focused review
62 lines
1.8 KiB
JavaScript
62 lines
1.8 KiB
JavaScript
/**
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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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/* Breadth-first traversal */
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// Represent the graph with an adjacency list to access all neighbors of a given vertex
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function graphBFS(graph, startVet) {
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// Vertex traversal sequence
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const res = [];
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// Hash set recording visited vertices
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const visited = new Set();
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visited.add(startVet);
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// Use a queue to implement BFS
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const que = [startVet];
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// Starting from startVet, loop until all reachable vertices have been visited
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while (que.length) {
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const vet = que.shift(); // Dequeue the front vertex
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res.push(vet); // Record the visited vertex
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// Traverse all neighbors of this vertex
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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; // Skip vertices that have already been visited
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}
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que.push(adjVet); // Enqueue only unvisited vertices
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visited.add(adjVet); // Mark this vertex as visited
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}
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}
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// Return the vertex traversal sequence
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return res;
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}
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/* Driver code */
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/* Initialize the undirected graph */
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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('\nGraph after initialization:');
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graph.print();
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/* Breadth-first traversal */
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const res = graphBFS(graph, v[0]);
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console.log('\nVertex sequence from breadth-first traversal (BFS):');
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console.log(Vertex.vetsToVals(res));
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