solves clone graph (#133) in python

Author: sumanth-botlagunta

python/clone_graph.py

@@ -0,0 +1,19 @@
+# https://leetcode.com/problems/clone-graph/description/
+# T: O(n) where n is the number of nodes in the graph
+# S: O(n) where n is the number of nodes in the graph
+
+class Solution:
+    def cloneGraph(self, node: 'Node') -> 'Node':
+        if not node: 
+            return node
+        d = {node.val: Node(node.val, [])}
+        q = deque([node])
+        while q:
+            cur_node = q.pop()
+            cur_res = d[cur_node.val]
+            for n in cur_node.neighbors:
+                if n.val not in d:
+                    q.append(n)
+                    d[n.val] = Node(n.val, [])
+                cur_res.neighbors.append(d[n.val])
+        return d[node.val]