DFS

Depth First Traversal algorithm for a graph is implemented in Python. Driver code to test the same is also provided

dfs.py

@@ -0,0 +1,58 @@
+# Python3 program to print DFS traversal  
+
+from collections import defaultdict 
+  
+# This class represents a directed graph using 
+# adjacency list representation 
+class Graph: 
+  
+    # Constructor 
+    def __init__(self): 
+  
+        # default dictionary to store graph 
+        self.graph = defaultdict(list) 
+  
+    # function to add an edge to graph 
+    def addEdge(self, u, v): 
+        self.graph[u].append(v) 
+  
+    # A function used by DFS 
+    def DFSUtil(self, v, visited): 
+  
+        # Mark the current node as visited  
+        # and print it 
+        visited[v] = True
+        print(v, end = ' ') 
+  
+        # Recur for all the vertices  
+        # adjacent to this vertex 
+        for i in self.graph[v]: 
+            if visited[i] == False: 
+                self.DFSUtil(i, visited) 
+  
+    # The function to do DFS traversal. It uses 
+    # recursive DFSUtil() 
+    def DFS(self, v): 
+  
+        # Mark all the vertices as not visited 
+        visited = [False] * (len(self.graph)) 
+  
+        # Call the recursive helper function  
+        # to print DFS traversal 
+        self.DFSUtil(v, visited) 
+  
+# Driver code 
+  
+# Create a graph given  
+# in the above diagram 
+g = Graph() 
+g.addEdge(0, 1) 
+g.addEdge(0, 2) 
+g.addEdge(1, 2) 
+g.addEdge(2, 0) 
+g.addEdge(2, 3) 
+g.addEdge(3, 3) 
+  
+print("Following is DFS from (starting from vertex 2)") 
+g.DFS(2) 
+