// create a graph class
class Graph {
  // defining vertex array and
  // adjacent list
  constructor (noOfVertices) {
    this.noOfVertices = noOfVertices
    this.AdjList = new Map()
  }

  // functions to be implemented

  // addVertex(v)
  // addEdge(v, w)
  // printGraph()

  // bfs(v)
  // dfs(v)
}

// add vertex to the graph
addVertex(v)
{
  // initialize the adjacent list with a
  // null array
  this.AdjList.set(v, [])
}

// add edge to the graph
addEdge(v, w)
{
  // get the list for vertex v and put the
  // vertex w denoting edge between v and w
  this.AdjList.get(v).push(w)

  // Since graph is undirected,
  // add an edge from w to v also
  this.AdjList.get(w).push(v)
}

// Prints the vertex and adjacency list
printGraph()
{
  // get all the vertices
  var get_keys = this.AdjList.keys()

  // iterate over the vertices
  for (var i of get_keys) {
    // great the corresponding adjacency list
    // for the vertex
    var get_values = this.AdjList.get(i)
    var conc = ''

    // iterate over the adjacency list
    // concatenate the values into a string
    for (var j of get_values) { conc += j + ' ' }

    // print the vertex and its adjacency list
    console.log(i + ' -> ' + conc)
  }
}

// Example
var graph = new Graph(6)
var vertices = ['A', 'B', 'C', 'D', 'E', 'F']

// adding vertices
for (var i = 0; i < vertices.length; i++) {
  g.addVertex(vertices[i])
}

// adding edges
g.addEdge('A', 'B')
g.addEdge('A', 'D')
g.addEdge('A', 'E')
g.addEdge('B', 'C')
g.addEdge('D', 'E')
g.addEdge('E', 'F')
g.addEdge('E', 'C')
g.addEdge('C', 'F')

// prints all vertex and
// its adjacency list
// A -> B D E
// B -> A C
// C -> B E F
// D -> A E
// E -> A D F C
// F -> E C
g.printGraph()