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/*
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* File: graph_bfs.rs
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* Created Time: 2023-07-12
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* Author: night-cruise (2586447362@qq.com)
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*/
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mod graph_adjacency_list;
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use graph_adjacency_list::GraphAdjList;
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use graph_adjacency_list::{vals_to_vets, vets_to_vals, Vertex};
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use std::collections::{HashSet, VecDeque};
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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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fn graph_bfs(graph: GraphAdjList, start_vet: Vertex) -> Vec<Vertex> {
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// 顶点遍历序列
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let mut res = vec![];
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// 哈希集合,用于记录已被访问过的顶点
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let mut visited = HashSet::new();
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visited.insert(start_vet);
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// 队列用于实现 BFS
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let mut que = VecDeque::new();
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que.push_back(start_vet);
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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.is_empty() {
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let vet = que.pop_front().unwrap(); // 队首顶点出队
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res.push(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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if let Some(adj_vets) = graph.adj_list.get(&vet) {
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for &adj_vet in adj_vets {
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if visited.contains(&adj_vet) {
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continue; // 跳过已被访问的顶点
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}
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que.push_back(adj_vet); // 只入队未访问的顶点
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visited.insert(adj_vet); // 标记该顶点已被访问
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}
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}
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}
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// 返回顶点遍历序列
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res
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}
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/* Driver Code */
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fn main() {
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/* 初始化无向图 */
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let v = vals_to_vets(vec![0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);
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let edges = vec![
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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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let graph = GraphAdjList::new(edges);
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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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let res = graph_bfs(graph, v[0]);
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println!("\n广度优先遍历(BFS)顶点序列为");
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println!("{:?}", vets_to_vals(res));
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}
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