Merge pull request #260 from Naveen963/patch-2

DFS in python

Author: seeditsolution

DFS

@@ -0,0 +1,89 @@
+# Python program to print DFS traversal for complete graph 
+
+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, 
+
+  
+
+        # 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 = len(self.graph)  #total vertices 
+
+  
+
+        # Mark all the vertices as not visited 
+
+        visited =[False]*(V) 
+
+  
+
+        # Call the recursive helper function to print 
+
+        # DFS traversal starting from all vertices one 
+
+        # by one 
+
+        for i in range(V): 
+
+            if visited[i] == False: 
+
+                self.DFSUtil(i, visited) 
+
+