Create DFSUsingRecursion.java

Author: harshithasudhakar

Graphs/DFSUsingRecursion.java

@@ -0,0 +1,65 @@
+import java.util.*;
+
+class DFSUsingRecursion{
+    static class Edge{
+        int src,dest;
+        
+        Edge(int src, int dest){
+            this.src = src;
+            this.dest = dest;
+        }
+    }
+
+    static void makeGraph(ArrayList<ArrayList<Integer>> graph, int v){
+        for(int i = 0; i<v; i++){
+            graph.add(new ArrayList<Integer>());
+        }
+    }
+
+    static void fillGraph(ArrayList<ArrayList<Integer>> graph, int v, ArrayList<Edge> edgeList){
+        for(int i=0; i<edgeList.size(); i++){
+            int s = edgeList.get(i).src;
+            int d = edgeList.get(i).dest;
+            graph.get(s).add(d);
+        }
+    }
+
+    static void dfs(ArrayList<ArrayList<Integer>> graph, int v, boolean[] visited, int src){
+        if(visited[src]){
+            return;
+        }
+
+        visited[src] = true;
+        System.out.println(src);
+
+        for(int neighbour: graph.get(src)){
+            if(!visited[neighbour]){
+                dfs(graph, visited, neighbour);
+            }
+        }
+    }
+
+    public static void main(String[] args){
+        Scanner input = new Scanner(System.in);
+
+        System.out.println("Enter the number of vertices: ");
+        int v = input.nextInt();
+        System.out.println("Enter the number of edges: ");
+        int e = input.nextInt();
+
+        ArrayList<Edge> edgeList = new ArrayList<Edge>();
+
+        for(int i = 0; i<e; i++){
+            edgeList.add(new Edge(input.nextInt(), input.nextInt()));
+        }
+
+        ArrayList<ArrayList<Integer>> graph = new ArrayList<ArrayList<Integer>>();
+        makeGraph(graph, v);
+        fillGraph(graph, v, edgeList);
+
+        boolean[] visited = new boolean[v];
+        dfs(graph, v, visited, 0);
+
+        input.close();
+    }
+}