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

137 lines
4.1 KiB
Rust

/*
* File: graph_adjacency_matrix.rs
* Created Time: 2023-07-12
* Author: night-cruise (2586447362@qq.com)
*/
/* Type of undirected graph implemented based on adjacency matrix */
pub struct GraphAdjMat {
// Vertex list, elements represent "vertex value", index represents "vertex index"
pub vertices: Vec<i32>,
// Adjacency matrix, row and column indices correspond to "vertex index"
pub adj_mat: Vec<Vec<i32>>,
}
impl GraphAdjMat {
/* Constructor */
pub fn new(vertices: Vec<i32>, edges: Vec<[usize; 2]>) -> Self {
let mut graph = GraphAdjMat {
vertices: vec![],
adj_mat: vec![],
};
// Add vertex
for val in vertices {
graph.add_vertex(val);
}
// Add edge
// Please note, edges elements represent vertex indices, corresponding to vertices elements indices
for edge in edges {
graph.add_edge(edge[0], edge[1])
}
graph
}
/* Get the number of vertices */
pub fn size(&self) -> usize {
self.vertices.len()
}
/* Add vertex */
pub fn add_vertex(&mut self, val: i32) {
let n = self.size();
// Add new vertex value to the vertex list
self.vertices.push(val);
// Add a row to the adjacency matrix
self.adj_mat.push(vec![0; n]);
// Add a column to the adjacency matrix
for row in &mut self.adj_mat {
row.push(0);
}
}
/* Remove vertex */
pub fn remove_vertex(&mut self, index: usize) {
if index >= self.size() {
panic!("index error")
}
// Remove vertex at `index` from the vertex list
self.vertices.remove(index);
// Remove the row at `index` from the adjacency matrix
self.adj_mat.remove(index);
// Remove the column at `index` from the adjacency matrix
for row in &mut self.adj_mat {
row.remove(index);
}
}
/* Add edge */
pub fn add_edge(&mut self, i: usize, j: usize) {
// Parameters i, j correspond to vertices element indices
// Handle index out of bounds and equality
if i >= self.size() || j >= self.size() || i == j {
panic!("index error")
}
// In an undirected graph, the adjacency matrix is symmetric about the main diagonal, i.e., satisfies (i, j) == (j, i)
self.adj_mat[i][j] = 1;
self.adj_mat[j][i] = 1;
}
/* Remove edge */
// Parameters i, j correspond to vertices element indices
pub fn remove_edge(&mut self, i: usize, j: usize) {
// Parameters i, j correspond to vertices element indices
// Handle index out of bounds and equality
if i >= self.size() || j >= self.size() || i == j {
panic!("index error")
}
self.adj_mat[i][j] = 0;
self.adj_mat[j][i] = 0;
}
/* Print adjacency matrix */
pub fn print(&self) {
println!("Vertex list = {:?}", self.vertices);
println!("Adjacency matrix =");
println!("[");
for row in &self.adj_mat {
println!(" {:?},", row);
}
println!("]")
}
}
/* Driver Code */
fn main() {
/* Initialize undirected graph */
// Please note, edges elements represent vertex indices, corresponding to vertices elements indices
let vertices = vec![1, 3, 2, 5, 4];
let edges = vec![[0, 1], [0, 3], [1, 2], [2, 3], [2, 4], [3, 4]];
let mut graph = GraphAdjMat::new(vertices, edges);
println!("\nAfter initialization, the graph is");
graph.print();
/* Add edge */
// Indices of vertices 1, 2 are 0, 2 respectively
graph.add_edge(0, 2);
println!("\nAfter adding edge 1-2, the graph is");
graph.print();
/* Remove edge */
// Indices of vertices 1, 3 are 0, 1 respectively
graph.remove_edge(0, 1);
println!("\nAfter removing edge 1-3, the graph is");
graph.print();
/* Add vertex */
graph.add_vertex(6);
println!("\nAfter adding vertex 6, the graph is");
graph.print();
/* Remove vertex */
// Index of vertex 3 is 1
graph.remove_vertex(1);
println!("\nAfter removing vertex 3, the graph is");
graph.print();
}