Struct Graph 

pub struct Graph<T> {
    pub graph: HashMap<Rc<TreeNode<T>>, Vec<(Rc<TreeNode<T>>, Option<i32>)>>,
}

A graph data structure represented as an adjacency list

This structure represents a Graph where each node is a Rc reference counted TreeNode<T>, and edges are stored as a vector of tuples containing Rc reference counted neighboring nodes and their optional weights

Fields

graph: HashMap<Rc<TreeNode<T>>, Vec<(Rc<TreeNode<T>>, Option<i32>)>>

The adjacency list representation of this Graph

This HashMap stores the graph’s structure

• The keys are Rc reference counted TreeNode<T> objects representing the graph’s nodes
• The values are vectors of tuples, each representing an edge from the key node:
  • The first element of the tuple is a Rc reference counted TreeNode<T> representing the neighboring node.
  • The second element of the tuple is an optional i32 (Option<i32>), representing the weight of the edge (if any).

This design allows the graph to represent both weighted and unweighted graphs.

Implementations

impl<T: Eq + Hash + Clone> Graph<T>

pub fn new() -> Self

Creates a new and empty Graph.

Returns

• A newly made Graph instance

Examples

use dsa::data_structures::graph::Graph;

let graph: Graph<i32> = Graph::new();
assert!(graph.graph.is_empty());

pub fn add_node(&mut self, node: Rc<TreeNode<T>>)

Adds a new node to this Graph.

If the node already exists, this method does nothing.

Parameters

• node: The reference counted, Rc, TreeNode to be added to the graph.

Examples

use std::rc::Rc;
use dsa::data_structures::graph::Graph;
use dsa::data_structures::tree::TreeNode;

let node = Rc::new(TreeNode::new(1));
let mut graph = Graph::new();
graph.add_node(Rc::clone(&node));

assert!(graph.graph.contains_key(&node));

pub fn remove_node(&mut self, node: Rc<TreeNode<T>>)

Removes a node and all its edges from the Graph.

This method removes the node from the graph and ensures that any edges connected to it are also removed.

Parameters

• node: The TreeNode to be removed from the graph.

Examples

use std::rc::Rc;
use dsa::data_structures::graph::Graph;
use dsa::data_structures::tree::TreeNode;

let node1 = Rc::new(TreeNode::new(1));
let node2 = Rc::new(TreeNode::new(2));
let mut graph = Graph::new();
graph.add_node(Rc::clone(&node1));
graph.add_node(Rc::clone(&node2));
graph.add_edge(Rc::clone(&node1), Rc::clone(&node2), Some(10));

graph.remove_node(Rc::clone(&node1));
assert!(!graph.graph.contains_key(&node1));
assert!(graph.graph.contains_key(&node2));
assert!(graph.graph[&node2].is_empty());

pub fn add_edge( &mut self, a: Rc<TreeNode<T>>, b: Rc<TreeNode<T>>, weight: Option<i32>, )

Adds an edge between two nodes in the Graph.

If either node does not exist, it is added to the graph automatically. The edge is added in both directions, making the graph undirected.

Parameters

• a: The first TreeNode as a reference counting Rc pointer
• b: The second TreeNode as a reference counting Rc pointer
• weight: An optional weight for the edge.

Examples

use std::rc::Rc;
use dsa::data_structures::graph::Graph;
use dsa::data_structures::tree::TreeNode;

let node1 = Rc::new(TreeNode::new(1));
let node2 = Rc::new(TreeNode::new(2));
let mut graph = Graph::new();
graph.add_edge(Rc::clone(&node1), Rc::clone(&node2), Some(10));

assert!(graph.graph.contains_key(&node1));
assert!(graph.graph.contains_key(&node2));
assert_eq!(graph.graph[&node1].len(), 1);
assert_eq!(graph.graph[&node2].len(), 1);

pub fn remove_edge(&mut self, a: Rc<TreeNode<T>>, b: Rc<TreeNode<T>>)

Removes an edge between two nodes in the Graph.

If either node does not exist or the edge does not exist, this method does nothing.

Parameters

• a: The first TreeNode as a reference counting Rc pointer.
• b: The second TreeNode as a reference counting Rc pointer.

Examples

use std::rc::Rc;
use dsa::data_structures::graph::Graph;
use dsa::data_structures::tree::TreeNode;

let node1 = Rc::new(TreeNode::new(1));
let node2 = Rc::new(TreeNode::new(2));
let mut graph = Graph::new();
graph.add_edge(Rc::clone(&node1), Rc::clone(&node2), Some(10));
graph.remove_edge(Rc::clone(&node1), Rc::clone(&node2));

assert!(graph.graph[&node1].is_empty());
assert!(graph.graph[&node2].is_empty());