Refactoring

- changed to maven
- modified hashMap and HashSet to Tree
- modified files path

src/main/java/berack96/lib/graph/visit/impl/DFS.java

@@ -0,0 +1,49 @@
+package berack96.lib.graph.visit.impl;
+
+import berack96.lib.graph.Graph;
+import berack96.lib.graph.visit.VisitStrategy;
+
+import java.util.Iterator;
+import java.util.Stack;
+import java.util.function.Consumer;
+
+/**
+ * Depth-first search<br>
+ * The algorithm starts at the root node and explores as far as possible along each branch before backtracking.
+ *
+ * @param <V> the vertex of the graph
+ * @author Berack96
+ */
+public class DFS<V> implements VisitStrategy<V> {
+
+    @Override
+    public VisitInfo<V> visit(Graph<V> graph, V source, Consumer<V> visit) throws NullPointerException, IllegalArgumentException {
+        VisitInfo<V> info = new VisitInfo<>(source);
+        final Stack<V> toVisit = new Stack<>();
+
+        toVisit.push(source);
+
+        while (!toVisit.isEmpty()) {
+            V current = toVisit.peek();
+            boolean hasChildToVisit = false;
+            Iterator<V> iter = graph.getChildren(current).iterator();
+
+            while (iter.hasNext() && !hasChildToVisit) {
+                V child = iter.next();
+                if (!info.isDiscovered(child)) {
+                    hasChildToVisit = true;
+                    toVisit.push(child);
+                    info.setParent(current, child);
+                }
+            }
+
+            if (!hasChildToVisit) {
+                toVisit.pop();
+                info.setVisited(current);
+                if (visit != null)
+                    visit.accept(current);
+            }
+        }
+        return info;
+    }
+}