DFS.java

import java.util.LinkedList;


public class DFS {

    private static class Graph {

        private int vertices;
        private LinkedList<Integer>[] adjacencyList;

        public Graph(int vertices) {
            this.vertices = vertices;
            adjacencyList = new LinkedList[vertices];

            for (int i = 0; i < vertices; i++) {
                adjacencyList[i] = new LinkedList<>();
            }
        }

        public void addEdge(int source, int destination) {
            adjacencyList[source].add(destination);
        }


        public void dfs(int startVertex) {
            boolean[] visited = new boolean[vertices];
            dfsUtil(startVertex, visited);
        }

        private void dfsUtil(int currentVertex, boolean[] visited) {
            visited[currentVertex] = true;
            System.out.print(currentVertex + " ");

            LinkedList<Integer> adjacentVertices = adjacencyList[currentVertex];
            for (int adjacentVertex : adjacentVertices) {
                if (!visited[adjacentVertex]) {
                    dfsUtil(adjacentVertex, visited);
                }
            }
        }
    }


    public static void main(String[] args) {

        Graph graph = new Graph(6);
        graph.addEdge(0, 1);
        graph.addEdge(0, 2);
        graph.addEdge(1, 3);
        graph.addEdge(1, 4);
        graph.addEdge(2, 4);
        graph.addEdge(3, 4);
        graph.addEdge(3, 5);

        System.out.println("DFS traversal starting from vertex 0:");
        graph.dfs(0);
        System.out.println();
        
    }
}