Add Bellman-Ford.

src/data-structures/graph/Graph.js

@@ -32,6 +32,13 @@ export default class Graph {
     return vertex.getNeighbors();
   }
 
+  /**
+   * @return {GraphVertex[]}
+   */
+  getAllVertices() {
+    return Object.values(this.vertices);
+  }
+
   /**
    * @param {GraphEdge} edge
    * @returns {Graph}

src/data-structures/graph/__test__/Graph.test.js

@@ -28,6 +28,10 @@ describe('Graph', () => {
 
     graph.addEdge(edgeAB);
 
+    expect(graph.getAllVertices().length).toBe(2);
+    expect(graph.getAllVertices()[0]).toEqual(vertexA);
+    expect(graph.getAllVertices()[1]).toEqual(vertexB);
+
     const graphVertexA = graph.findVertexByKey(vertexA.getKey());
     const graphVertexB = graph.findVertexByKey(vertexB.getKey());