71 lines
2.2 KiB
Rust
71 lines
2.2 KiB
Rust
/*
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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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/* Breadth-first traversal */
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// Use adjacency list to represent the graph, to obtain all adjacent vertices of a specified vertex
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fn graph_bfs(graph: GraphAdjList, start_vet: Vertex) -> Vec<Vertex> {
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// Vertex traversal sequence
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let mut res = vec![];
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// Hash set, used to record visited vertices
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let mut visited = HashSet::new();
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visited.insert(start_vet);
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// Queue used to implement BFS
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let mut que = VecDeque::new();
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que.push_back(start_vet);
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// Starting from vertex vet, loop until all vertices are visited
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while !que.is_empty() {
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let vet = que.pop_front().unwrap(); // Dequeue the vertex at the head of the queue
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res.push(vet); // Record visited vertex
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// Traverse all adjacent vertices of that vertex
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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; // Skip already visited vertices
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}
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que.push_back(adj_vet); // Only enqueue unvisited vertices
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visited.insert(adj_vet); // Mark the vertex as visited
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}
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}
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}
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// Return the vertex traversal sequence
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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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/* Initialize undirected graph */
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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!("\nAfter initialization, the graph is");
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graph.print();
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/* Breadth-first traversal */
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let res = graph_bfs(graph, v[0]);
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println!("\nBreadth-first traversal (BFS) vertex sequence is");
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println!("{:?}", vets_to_vals(res));
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}
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