Find the longest path between any two pairs of vertices in a graph

dfs.js

/*
We are given a map of cities connected with each other via cable lines such that there is no cycle between any two cities. We need to find the maximum length of cable between any two cities for given city map.
Input : n = 6 
1 2 3  // Cable length from 1 to 2 (or 2 to 1) is 3
2 3 4
2 6 2
6 4 6
6 5 5
Output: maximum length of cable = 12
*/

class Node {
	constructor(node_name, weight, currentSum) {
		this.node_name = node_name;
		this.weight = weight;
		this.currentSum = currentSum;
	}
}

class Graph {
	constructor(num_nodes) {
		// this.adjacencyList looks like this: "[[],[],[],[],[],[]]"
		this.adjacencyList = Array.from({length: num_nodes}, e => Array());
		this.num_nodes = num_nodes;
	}
	addEdge(x,y,weight) {
		this.adjacencyList[x].push(new Node(y, weight, 0));
		this.adjacencyList[y].push(new Node(x, weight, 0));
		return this.adjacencyList;
	}
	longest_path_between_any_pair() {
		var max_sum=0;
		for(var i=0; i<this.num_nodes; i++) {
			var visited = new Array(this.num_nodes).fill(false);
			var stack = [];
			if(this.adjacencyList[i].length==0)
				continue;
			stack.push(new Node(i, 0, 0));
			while(stack.length>0) {
				var curr = stack.pop();
				if(visited[curr.node_name]==true)
					continue;
				visited[curr.node_name]=true;
				if(curr.currentSum>max_sum)
					max_sum=curr.currentSum;
				for(var neighbor=0; neighbor<this.adjacencyList[curr.node_name].length; neighbor++) {
					stack.push(new Node(this.adjacencyList[curr.node_name][neighbor].node_name,
						this.adjacencyList[curr.node_name][neighbor].weight,
						curr.currentSum + this.adjacencyList[curr.node_name][neighbor].weight));
				}
			}
		}
		return max_sum;
	}
}

var g = new Graph(7); //7 because we aren't starting at 0. So we need x[1],...x[6] 
g.addEdge(1,2,3);
g.addEdge(2,3,4);
g.addEdge(2,6,2);
g.addEdge(6,4,6);
g.addEdge(6,5,5);
g.longest_path_between_any_pair();

// adjacencyList looks like this:
/*
[
	[],
	[{"neighbor":2,"weight":3,"path_sum":0}],
	[{"neighbor":1,"weight":3,"path_sum":0},{"neighbor":3,"weight":4,"path_sum":0},{"neighbor":6,"weight":2,"path_sum":0}],
	[{"neighbor":2,"weight":4,"path_sum":0}],
	[{"neighbor":6,"weight":6,"path_sum":0}],
	[{"neighbor":6,"weight":5,"path_sum":0}],
	[{"neighbor":2,"weight":2,"path_sum":0},{"neighbor":4,"weight":6,"path_sum":0},{"neighbor":5,"weight":5,"path_sum":0}]
]
*/