Added Depth First Search

Author: OmkarPathak

pygorithm/searching/depth_first_search.py

@@ -0,0 +1,17 @@
+# Author: OMKAR PATHAK
+# Created On: 1st August 2017
+
+#  depth first search algorithm
+def dfs(graph, start, path = []):
+    # check if graph is empty or start vertex is none
+    if start not in graph or graph[start] is None or graph[start] == []:
+        return None
+    path = path + [start]
+    for edge in graph[start]:
+        if edge not in path:
+            path = dfs(graph, edge, path)
+    return path
+
+# time complexities
+def time_complexities():
+    return '''O(V + E) where V = Number of vertices and E = Number of Edges'''