add dfs algorithm

README.md

@@ -1 +1,10 @@
-# repo3
+# repo3
+
+### How to contribute?
+
+* Fork this repository
+* Create a new cpp file 
+* Add any code
+* Push PR
+* Follow Developer & Star the repo
+* All done!

dinosaulo.cpp

@@ -0,0 +1,57 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+// Graph class represents a directed graph
+// using adjacency list representation
+class Graph 
+{
+public:
+    map<int, bool> visited;
+    map<int, list<int>> adj;
+
+    // function to add an edge to graph
+    void addEdge(int v, int w);
+
+    // DFS traversal of the vertices
+    // reachable from v
+    void DFS(int v);
+};
+
+void Graph::addEdge(int v, int w)
+{
+    adj[v].push_back(w); // Add w to v’s list.
+}
+
+void Graph::DFS(int v)
+{
+    // Mark the current node as visited and
+    // print it
+    visited[v] = true;
+    cout << v << " ";
+
+    // Recur for all the vertices adjacent
+    // to this vertex
+    list<int>::iterator i;
+    for (i = adj[v].begin(); i != adj[v].end(); ++i)
+        if (!visited[*i])
+            DFS(*i);
+}
+
+// Driver code
+int main()
+{
+    // Create a graph given in the above diagram
+    Graph g;
+    g.addEdge(0, 1);
+    g.addEdge(0, 2);
+    g.addEdge(1, 2);
+    g.addEdge(2, 0);
+    g.addEdge(2, 3);
+    g.addEdge(3, 3);
+
+    cout << "Following is Depth First Traversal"
+            " (starting from vertex 2) \n";
+    g.DFS(2);
+
+    return 0;
+}