DepthFirstSearch_DFS.java

/*
 *        Depth first search 
 */

import java.util.ArrayList;

public class DepthFirstSearch_DFS {

    static class Edge {
        int src;
        int dest;
        int weight;

        Edge(int s, int d, int w) {
            this.src = s;
            this.dest = d;
            this.weight = w;
        }
    }

    public static void dfs(ArrayList<Edge>[] graph, int curr, boolean vis[]) {
        // visit
        System.out.print(curr + " ");
        vis[curr] = true;

        for (int i = 0; i < graph[curr].size(); i++) {
            Edge e = graph[curr].get(i);
            if (!vis[e.dest]) {
                dfs(graph, e.dest, vis);
            }
        }
    }

    public static void main(String[] args) {
        int v = 7;
        ArrayList<Edge>[] graph = new ArrayList[v];

        for (int i = 0; i < v; i++) {
            graph[i] = new ArrayList<>();
        }

        // 0 vertex
        graph[0].add(new Edge(0, 1, 1));
        graph[0].add(new Edge(0, 2, 1));

        // 1 vertex
        graph[1].add(new Edge(1, 0, 1));
        graph[1].add(new Edge(1, 3, 1));

        // 2 vertex
        graph[2].add(new Edge(2, 0, 1));
        graph[2].add(new Edge(2, 1, 1));

        // 3 vertex
        graph[3].add(new Edge(3, 1, 1));
        graph[3].add(new Edge(3, 4, 1));
        graph[3].add(new Edge(3, 5, 1));

        // 4 vertex
        graph[4].add(new Edge(4, 3, 1));
        graph[4].add(new Edge(4, 3, 1));
        graph[4].add(new Edge(4, 3, 1));

        // 5 vertex
        graph[5].add(new Edge(5, 4, 1));
        graph[5].add(new Edge(5, 3, 1));
        graph[5].add(new Edge(5, 6, 1));

        // 6 vertex
        graph[6].add(new Edge(6, 5, 1));

        dfs(graph, 0, new boolean[v]);

    }

}