merge: Add Graph3 (add DFS in Iterative Way) (#944)

* Add Graph3 (add DFS in Iterative Way)

* Remove example code and add test code (Graph3)

* Remove redundant code (like return undefined)

Data-Structures/Graph/test/Graph3.test.js

@@ -0,0 +1,75 @@
+import { Graph } from '../Graph3'
+
+describe('Test Graph3', () => {
+  const g = new Graph()
+
+  // Add Vertices
+  g.addVertex('A')
+  g.addVertex('B')
+  g.addVertex('C')
+  g.addVertex('D')
+  g.addVertex('E')
+  g.addVertex('F')
+
+  // Add Edges
+  g.addEdge('A', 'B')
+  g.addEdge('A', 'C')
+  g.addEdge('B', 'D')
+  g.addEdge('C', 'E')
+  g.addEdge('D', 'E')
+  g.addEdge('D', 'F')
+  g.addEdge('E', 'F')
+
+  /**
+   * A - B - D
+   * |      / \
+   * C - - E - F
+   *
+   * DFS(Iterative): A-C-E-F-D-B
+   * DFS(Recursive): A-B-D-E-C-F
+   * BFS: A-B-C-D-E-F
+   */
+  it('Check iterative DFS List', () => {
+    const iterativeDFSList = g.DFSIterative('A')
+    expect(iterativeDFSList).toEqual(['A', 'C', 'E', 'F', 'D', 'B'])
+  })
+
+  it('Check recursive DFS List', () => {
+    const recursiveDFSList = g.DFS('A')
+    expect(recursiveDFSList).toEqual(['A', 'B', 'D', 'E', 'C', 'F'])
+  })
+
+  it('Check BFS List', () => {
+    const BFSList = g.BFS('A')
+    expect(BFSList).toEqual(['A', 'B', 'C', 'D', 'E', 'F'])
+  })
+
+  /**
+   * Test After Remove 'B' Vertex
+   * A       D
+   * |      / \
+   * C - - E - F
+   *
+   * DFS(Iterative): A-C-E-F-D
+   * DFS(Recursive): A-C-E-D-F
+   * BFS: A-C-E-D-F
+   */
+
+  it('Check iterative DFS List After Removing Vertex B', () => {
+    g.removeVertex('B')
+    const iterativeDFSList = g.DFSIterative('A')
+    expect(iterativeDFSList).toEqual(['A', 'C', 'E', 'F', 'D'])
+  })
+
+  it('Check recursive DFS List After Removing Vertex B', () => {
+    g.removeVertex('B')
+    const recursiveDFSList = g.DFS('A')
+    expect(recursiveDFSList).toEqual(['A', 'C', 'E', 'D', 'F'])
+  })
+
+  it('Check BFS List After Removing Vertex B', () => {
+    g.removeVertex('B')
+    const BFSList = g.BFS('A')
+    expect(BFSList).toEqual(['A', 'C', 'E', 'D', 'F'])
+  })
+})