Added DFS (UNIQUE VISITS)

Author: indraantoor

Graph Data Structures/Graph Traversal/Depth-First Traversal/Depth-First Traversal (Unique Visits)/GraphTraverser.java

@@ -0,0 +1,75 @@
+/*
+ If there was a cycle, like if there was a path from one
+ vertex to itself, we would be stuck in an infinite loop, continuously
+ iterating over the same neighbors. To account for this, we can use an
+ ArrayList to keep track of all the vertices that we have visited.
+ */
+
+// USE GRAPH FILE FROM GRAPH FOLDER
+
+import java.util.ArrayList;
+
+class GraphTraverser {
+    public static void depthFirstTraversal(Vertex start, ArrayList<Vertex> visitedVertices) {
+        System.out.println(start.getData());
+
+        if (start.getEdges().size() > 0) {
+            Vertex neighbor = start.getEdges().get(0).getEnd();
+
+            if (!visitedVertices.contains(neighbor)) {
+                visitedVertices.add(neighbor);
+                GraphTraverser.depthFirstTraversal(neighbor, visitedVertices);
+            }
+        }
+    }
+
+    // USE TO TEST THE GRAPH
+    class TestGraph {
+        private Graph testGraph;
+
+        public TestGraph() {
+            this.testGraph = new Graph(false, true);
+            Vertex startNode = testGraph.addVertex("v0.0.0");
+            Vertex v1 = this.testGraph.addVertex("v1.0.0");
+            Vertex v2 = this.testGraph.addVertex("v2.0.0");
+
+            Vertex v11 = this.testGraph.addVertex("v1.1.0");
+            Vertex v12 = this.testGraph.addVertex("v1.2.0");
+            Vertex v21 = this.testGraph.addVertex("v2.1.0");
+
+            Vertex v111 = this.testGraph.addVertex("v1.1.1");
+            Vertex v112 = this.testGraph.addVertex("v1.1.2");
+            Vertex v121 = this.testGraph.addVertex("v1.2.1");
+            Vertex v211 = this.testGraph.addVertex("v2.1.1");
+
+            this.testGraph.addEdge(startNode, v1, null);
+            this.testGraph.addEdge(startNode, v2, null);
+
+            this.testGraph.addEdge(v1, v11, null);
+            this.testGraph.addEdge(v1, v12, null);
+            this.testGraph.addEdge(v2, v21, null);
+
+            this.testGraph.addEdge(v11, v111, null);
+            this.testGraph.addEdge(v11, v112, null);
+            this.testGraph.addEdge(v12, v121, null);
+            this.testGraph.addEdge(v21, v211, null);
+
+            // create a cycle
+            this.testGraph.addEdge(v211, v2, null);
+        }
+
+        public Vertex getStartingVertex() {
+            return this.testGraph.getVertices().get(0);
+        }
+    }
+
+    // MAIN METHOD
+    public static void main(String[] args) {
+        TestGraph test = new TestGraph();
+        Vertex startingVertex = test.getStartingVertex();
+        ArrayList<Vertex> visitedVertices = new ArrayList<Vertex>();
+        visitedVertices.add(startingVertex);
+
+        GraphTraverser.depthFirstTraversal(startingVertex, visitedVertices);
+    }
+}