Given the head of a graph, return a deep copy (clone) of the graph. Each node in the graph contains a label (int) and a list (List[UndirectedGraphNode]) of its neighbors. There is an edge between the given node and each of the nodes in its neighbors.


OJ's undirected graph serialization (so you can understand error output):
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 node is None:
            return 
        # add first node to queue
        queue=[node]
        # copy the first node x0 to x00
        head=UndirectedGraphNode(node.label)
        Map={node:head}
        while queue:
            cur=queue.pop(0)
            for neighbor in cur.neighbors:
                if neighbor not in Map:
                    queue.append(neighbor)
                    copy=UndirectedGraphNode(neighbor.label)
                    Map[neighbor]=copy
                    Map[cur].neighbors.append(copy)
                else:
                    Map[cur].neighbors.append(Map[neighbor])
        return head
        
        

810a5307aa1bbfc132d866bc9c13e08b83585141
Given the head of a graph, return a deep copy (clone) of the graph. Each node in the graph contains a label (int) and a list (List[UndirectedGraphNode]) of its neighbors. There is an edge between the given node and each of the nodes in its neighbors.


OJ's undirected graph serialization (so you can understand error output):
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 node is None:
            return 
        # add first node to queue
        queue=[node]
        # copy the first node x0 to x00
        head=UndirectedGraphNode(node.label)
        Map={node:head}
        while queue:
            cur=queue.pop(0)
            for neighbor in cur.neighbors:
                if neighbor not in Map:
                    queue.append(neighbor)
                    copy=UndirectedGraphNode(neighbor.label)
                    Map[neighbor]=copy
                    Map[cur].neighbors.append(copy)
                else:
                    Map[cur].neighbors.append(Map[neighbor])
        return head
        
        
