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* Update avatar's link in the landing page * Bug fixes * Move assets folder from overrides to docs * Reduce figures' corner radius * Update copyright * Update header image * Krahets -> krahets * Update the landing page
55 lines
2.1 KiB
Java
55 lines
2.1 KiB
Java
/**
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* File: graph_bfs.java
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* Created Time: 2023-02-12
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* Author: krahets (krahets@163.com)
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*/
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package chapter_graph;
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import java.util.*;
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import utils.*;
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public class graph_bfs {
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/* 广度优先遍历 */
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// 使用邻接表来表示图，以便获取指定顶点的所有邻接顶点
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static List<Vertex> graphBFS(GraphAdjList graph, Vertex startVet) {
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// 顶点遍历序列
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List<Vertex> res = new ArrayList<>();
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// 哈希表，用于记录已被访问过的顶点
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Set<Vertex> visited = new HashSet<>();
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visited.add(startVet);
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// 队列用于实现 BFS
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Queue<Vertex> que = new LinkedList<>();
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que.offer(startVet);
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// 以顶点 vet 为起点，循环直至访问完所有顶点
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while (!que.isEmpty()) {
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Vertex vet = que.poll(); // 队首顶点出队
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res.add(vet); // 记录访问顶点
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// 遍历该顶点的所有邻接顶点
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for (Vertex adjVet : graph.adjList.get(vet)) {
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if (visited.contains(adjVet))
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continue; // 跳过已被访问的顶点
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que.offer(adjVet); // 只入队未访问的顶点
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visited.add(adjVet); // 标记该顶点已被访问
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}
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}
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// 返回顶点遍历序列
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return res;
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}
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public static void main(String[] args) {
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/* 初始化无向图 */
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Vertex[] v = Vertex.valsToVets(new int[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 });
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Vertex[][] edges = { { v[0], v[1] }, { v[0], v[3] }, { v[1], v[2] }, { v[1], v[4] },
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{ v[2], v[5] }, { v[3], v[4] }, { v[3], v[6] }, { v[4], v[5] },
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{ v[4], v[7] }, { v[5], v[8] }, { v[6], v[7] }, { v[7], v[8] } };
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GraphAdjList graph = new GraphAdjList(edges);
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System.out.println("\n初始化后，图为");
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graph.print();
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/* 广度优先遍历 */
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List<Vertex> res = graphBFS(graph, v[0]);
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System.out.println("\n广度优先遍历（BFS）顶点序列为");
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System.out.println(Vertex.vetsToVals(res));
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}
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}
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