class Graph {

constructor() {

this.numberOfNodes = 0;

this.adjacentList = {};

}

addVertex(node) {

this.adjacentList[node] = []; // 空陣列代表該節點還沒連結到其他節點

this.numberOfNodes++;

}

addEdge(node1, node2) {

//uniderected Graph

this.adjacentList[node1].push(node2);

this.adjacentList[node2].push(node1);

}

showConnections() {

const allNodes = Object.keys(this.adjacentList);

for (let node of allNodes) {

let nodeConnections = this.adjacentList[node];

let connections = '';

let vertex;

for (vertex of nodeConnections) {

connections += vertex + ' ';

}

console.log(node + '-->' + connections);

}

}

}

var myGraph = new Graph();

myGraph.addVertex('0');

myGraph.addVertex('1');

myGraph.addVertex('2');

myGraph.addVertex('3');

myGraph.addVertex('4');

myGraph.addVertex('5');

myGraph.addVertex('6');

myGraph.addEdge('3', '1');

myGraph.addEdge('3', '4');

myGraph.addEdge('4', '2');

myGraph.addEdge('4', '5');

myGraph.addEdge('1', '2');

myGraph.addEdge('1', '0');

myGraph.addEdge('0', '2');

myGraph.addEdge('6', '5');

myGraph.showConnections();