Create Clone Graph.py

Author: sugia

Clone Graph.py

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+'''
+ Clone an undirected graph. Each node in the graph contains a label and a list of its neighbors.
+
+OJ's undirected graph serialization:
+
+Nodes are labeled uniquely.
+We use # as a separator for each node, and , as a separator for node label and each neighbor of the node.
+
+As an example, consider the serialized graph {0,1,2#1,2#2,2}.
+
+The graph has a total of three nodes, and therefore contains three parts as separated by #.
+
+    First node is labeled as 0. Connect node 0 to both nodes 1 and 2.
+    Second node is labeled as 1. Connect node 1 to node 2.
+    Third node is labeled as 2. Connect node 2 to node 2 (itself), thus forming a self-cycle.
+
+Visually, the graph looks like the following:
+
+       1
+      / \
+     /   \
+    0 --- 2
+         / \
+         \_/
+
+'''
+
+# Definition for a undirected graph node
+# class UndirectedGraphNode:
+#     def __init__(self, x):
+#         self.label = x
+#         self.neighbors = []
+
+class Solution:
+    # @param node, a undirected graph node
+    # @return a undirected graph node
+    def cloneGraph(self, node):
+        if not node:
+            return None
+        
+        dic = {}
+        mirror = UndirectedGraphNode(node.label)
+        dic[node] = mirror
+        
+        vec = [node]
+        visited = set([node])
+        while vec:
+            tmp = vec.pop()
+            for neighbor in tmp.neighbors:
+                if neighbor not in dic:
+                    mirror = UndirectedGraphNode(neighbor.label)
+                    dic[neighbor] = mirror
+                    
+                dic[tmp].neighbors.append(dic[neighbor])
+                
+                if neighbor not in visited:
+                    visited.add(neighbor)
+                    vec.append(neighbor)
+                    
+        return dic[node]
+