4.1 Routes between nodes - my solution with bfs

Author: amejiarosario

src/trees-and-graphs/graph.js

@@ -4,7 +4,7 @@ const Queue = require('../stacks-and-queues/queue');
  */
 class Graph {
   constructor() {
-    this.nodes = [];
+    this.nodes = {};
   }
 
   /**
@@ -42,8 +42,9 @@ Graph.prototype.bfs = function* (node) {
   queue.add(node);
 
   while(!queue.isEmpty()){
-    const adjacents = this.nodes[queue.remove()];
-    yield adjacents;
+    const current = queue.remove();
+    yield current;
+    const adjacents = this.nodes[current] || [];
     adjacents.forEach(function (adjNode) {
       queue.add(adjNode);
     });

src/trees-and-graphs/graph.spec.js

@@ -36,15 +36,19 @@ describe('Graph', function () {
       graph.add(1, 3);
     });
 
-    it('should get all adjancent in the first level', function () {
+    it('should get all adjancents from 0', function () {
       const bfs = graph.bfs(0);
-      expect(bfs.next().value).to.eql([1, 2]);
+      expect(bfs.next().value).to.eql(0);
+      expect(bfs.next().value).to.eql(1);
+      expect(bfs.next().value).to.eql(2);
+      expect(bfs.next().value).to.eql(3);
     });
 
-    it('should get 2nd level adjacents', function () {
-      const bfs = graph.bfs(0);
-      bfs.next();
-      expect(bfs.next().value).to.eql([3]);
+    it('should get all adjancents from 1', function () {
+      const bfs = graph.bfs(1);
+      expect(bfs.next().value).to.eql(1);
+      expect(bfs.next().value).to.eql(3);
+      expect(bfs.next().done).to.equal(true);
       expect(bfs.next().value).to.equal(undefined);
     });
   });

src/trees-and-graphs/routes-between-nodes.js

@@ -8,21 +8,16 @@ const Queue = require('../stacks-and-queues/queue');
  * @returns {boolean}
  */
 Graph.prototype.isConnected = function(node1, node2) {
-  const queue = new Queue();
+  const bfs = this.bfs(node1);
+  let next;
 
-  queue.add(node1);
+  do {
+    next = bfs.next();
 
-  while(!queue.isEmpty()) {
-    const current = queue.remove();
-
-    if(current === node2) {
+    if(next.value === node2) {
       return true;
     }
-
-    (this.nodes[current] || []).forEach(function (node) {
-      queue.add(node);
-    });
-  }
+  } while(!next.done);
 
   return false;
 };