using System;

using System.Collections.Generic;

​

public class Solution {

    public bool ValidPath(int n, int[][] edges, int source, int destination) {

        var graph = new Dictionary<int, List<int>>();

        var seen = new bool[n];

​

        foreach (var edge in edges) {

            int a = edge[0], b = edge[1];

            if (!graph.ContainsKey(a)) {

                graph[a] = new List<int>();

            }

            graph[a].Add(b);

            if (!graph.ContainsKey(b)) {

                graph[b] = new List<int>();

            }

            graph[b].Add(a);

        }

        return Dfs(graph, seen, source, destination);

    }

    private bool Dfs(Dictionary<int, List<int>> graph, bool[] seen, int currNode, int destination) {

        if (currNode == destination) {

            return true;

        }

        if (!seen[currNode]) {

            seen[currNode] = true;

            foreach (int nextNode in graph[currNode]) {

                if (Dfs(graph, seen, nextNode, destination)) {

                    return true;

                }

            }

        }

        return false;

    }

}

​

​