hello-algo/en/codes/rust/chapter_graph/graph_dfs.rs

62 lines
1.8 KiB
Rust

/*
* File: graph_dfs.rs
* Created Time: 2023-07-12
* Author: night-cruise (2586447362@qq.com)
*/
mod graph_adjacency_list;
use graph_adjacency_list::GraphAdjList;
use graph_adjacency_list::{vals_to_vets, vets_to_vals, Vertex};
use std::collections::HashSet;
/* Depth-first traversal helper function */
fn dfs(graph: &GraphAdjList, visited: &mut HashSet<Vertex>, res: &mut Vec<Vertex>, vet: Vertex) {
res.push(vet); // Record visited vertex
visited.insert(vet); // Mark the vertex as visited
// Traverse all adjacent vertices of that vertex
if let Some(adj_vets) = graph.adj_list.get(&vet) {
for &adj_vet in adj_vets {
if visited.contains(&adj_vet) {
continue; // Skip already visited vertices
}
// Recursively visit adjacent vertices
dfs(graph, visited, res, adj_vet);
}
}
}
/* Depth-first traversal */
// Use adjacency list to represent the graph, to obtain all adjacent vertices of a specified vertex
fn graph_dfs(graph: GraphAdjList, start_vet: Vertex) -> Vec<Vertex> {
// Vertex traversal sequence
let mut res = vec![];
// Hash set, used to record visited vertices
let mut visited = HashSet::new();
dfs(&graph, &mut visited, &mut res, start_vet);
res
}
/* Driver Code */
fn main() {
/* Initialize undirected graph */
let v = vals_to_vets(vec![0, 1, 2, 3, 4, 5, 6]);
let edges = vec![
[v[0], v[1]],
[v[0], v[3]],
[v[1], v[2]],
[v[2], v[5]],
[v[4], v[5]],
[v[5], v[6]],
];
let graph = GraphAdjList::new(edges);
println!("\nAfter initialization, the graph is");
graph.print();
/* Depth-first traversal */
let res = graph_dfs(graph, v[0]);
println!("\nDepth-first traversal (DFS) vertex sequence is");
println!("{:?}", vets_to_vals(res));
}