BFS shortest path in undirected graph | C# Online Compiler

BFS shortest path in undirected graph by neptunao

using System;
using System.Linq;
using System.Collections.Generic;

public class Node<T> {
	public T Value;
	
	public Node(T val) {
		Value = val;
	}
	
	public override string ToString() {
		return Value.ToString();
	}
}

public class Graph<T> {
	//private readonly List<Node<T>> _nodes;
	private readonly Dictionary<Node<T>, List<Node<T>>> _adj;
	
	public Graph() {
		//_nodes = new List<Node<T>>();
		_adj = new Dictionary<Node<T>, List<Node<T>>>();
	}
	
	public void AddEdge(Node<T> node1, Node<T> node2) { 
		if(!_adj.ContainsKey(node1))
			_adj[node1] = new List<Node<T>>();
		if(!_adj.ContainsKey(node2))
			_adj[node2] = new List<Node<T>>();
		_adj[node1].Add(node2);
		_adj[node2].Add(node1);
	}
	
	public Stack<Node<T>> ShortestPath(Node<T> source, Node<T> dest) {
		var path = new Dictionary<Node<T>, Node<T>>();
		var distance = new Dictionary<Node<T>, int>();
		foreach(var node in _adj.Keys) {
			distance[node] = -1;
		}
		distance[source] = 0;
		var q = new Queue<Node<T>>();
		q.Enqueue(source);
		while(q.Count > 0) {
			var node = q.Dequeue();
			foreach(var adj in _adj[node].Where(n => distance[n] == -1)) {
				distance[adj] = distance[node] + 1;
				path[adj] = node;
				q.Enqueue(adj);
			}
		}
		var res = new Stack<Node<T>>();
		var cur = dest;
		while(cur != source) {
			res.Push(cur);
			cur = path[cur];
		}
		res.Push(source);
		return res;
	}
}

public class Program
{
	public static void Main()
	{
		var g = new Graph<int>();
		var n1 = new Node<int>(1);
		var n2 = new Node<int>(2);
		var n3 = new Node<int>(3);
		var n4 = new Node<int>(4);
		var n5 = new Node<int>(5);
		var n6 = new Node<int>(6);
		var n7 = new Node<int>(7);
		g.AddEdge(n1, n2);
		g.AddEdge(n1, n3);
		g.AddEdge(n1, n4);
		g.AddEdge(n4, n5);
		g.AddEdge(n2, n6);
		g.AddEdge(n4, n7);
		g.AddEdge(n5, n6);
		g.AddEdge(n6, n7);
		
		Console.WriteLine("Shortest path is: {0}", string.Join("->", g.ShortestPath(n1, n7)));
	}
}

​x
 
using System;
using System.Linq;
using System.Collections.Generic;
​
public class Node<T> {
    public T Value;
    
    public Node(T val) {
        Value = val;
    }
    
    public override string ToString() {
        return Value.ToString();
    }
}
​
public class Graph<T> {
    //private readonly List<Node<T>> _nodes;
    private readonly Dictionary<Node<T>, List<Node<T>>> _adj;
    
    public Graph() {
        //_nodes = new List<Node<T>>();
        _adj = new Dictionary<Node<T>, List<Node<T>>>();
    }
    
    public void AddEdge(Node<T> node1, Node<T> node2) { 
        if(!_adj.ContainsKey(node1))
            _adj[node1] = new List<Node<T>>();
        if(!_adj.ContainsKey(node2))
            _adj[node2] = new List<Node<T>>();
        _adj[node1].Add(node2);
        _adj[node2].Add(node1);
    }
    
    public Stack<Node<T>> ShortestPath(Node<T> source, Node<T> dest) {
        var path = new Dictionary<Node<T>, Node<T>>();
        var distance = new Dictionary<Node<T>, int>();
        foreach(var node in _adj.Keys) {
            distance[node] = -1;
        }
        distance[source] = 0;
        var q = new Queue<Node<T>>();
        q.Enqueue(source);
        while(q.Count > 0) {
            var node = q.Dequeue();
            foreach(var adj in _adj[node].Where(n => distance[n] == -1)) {
                distance[adj] = distance[node] + 1;
                path[adj] = node;
                q.Enqueue(adj);
            }
        }
        var res = new Stack<Node<T>>();
        var cur = dest;
        while(cur != source) {
            res.Push(cur);
            cur = path[cur];
        }
        res.Push(source);
        return res;
    }
}
​
public class Program
{
    public static void Main()
    {
        var g = new Graph<int>();
        var n1 = new Node<int>(1);
        var n2 = new Node<int>(2);
        var n3 = new Node<int>(3);
        var n4 = new Node<int>(4);
        var n5 = new Node<int>(5);
        var n6 = new Node<int>(6);
        var n7 = new Node<int>(7);
        g.AddEdge(n1, n2);
        g.AddEdge(n1, n3);
        g.AddEdge(n1, n4);
        g.AddEdge(n4, n5);
        g.AddEdge(n2, n6);
        g.AddEdge(n4, n7);
        g.AddEdge(n5, n6);
        g.AddEdge(n6, n7);
        
        Console.WriteLine("Shortest path is: {0}", string.Join("->", g.ShortestPath(n1, n7)));
    }
}

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Last Run:	9:41:44 pm
Compile:	0s
Execute:	0.189s
Memory:	0b
CPU:	0s

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