------Question------
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 node0
to both nodes1
and2
. - Second node is labeled as
1
. Connect node1
to node2
. - Third node is labeled as
2
. Connect node2
to node2
(itself),thus forming a self-cycle.
Visually,the graph looks like the following:
1 / \ / \ 0 --- 2 / \ \_/
struct UndirectedGraphNode {
int label;
vector<UndirectedGraphNode *> neighbors;
UndirectedGraphNode(int x) : label(x) {};
};
class Solution {
public:
UndirectedGraphNode *cloneGraph(UndirectedGraphNode *node) {
if(!node) return NULL;
UndirectedGraphNode *current;
map<UndirectedGraphNode*,UndirectedGraphNode*> flag;
UndirectedGraphNode *root = cloneNode(node,flag);
return root;
}
UndirectedGraphNode * cloneNode(UndirectedGraphNode *source, map<UndirectedGraphNode*,UndirectedGraphNode*> &flag)
{
if(flag.find(source)!= flag.end()) return flag[source];
UndirectedGraphNode *target = new UndirectedGraphNode(source->label);
flag[source] = target;
for(vector<UndirectedGraphNode *>::iterator it = source->neighbors.begin(); it < source->neighbors.end(); it++ )
{
UndirectedGraphNode *newRoot = cloneNode(*it, flag);
target->neighbors.push_back(newRoot);
flag[*it] = newRoot;
}
return target;
}
};