Copy the non-circular band diagram

Clone an undirected graph. Each node in the graph contains a and label a lists of its neighbors .

OJ ' s undirected graph serialization:

Nodes is 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 # .

2. first node is labeled As 0 . Connect node 0  to both Nodes 1  and 2 .
4. second node is labeled As 1 . Connect node 1  to node 2 .
6. 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         /          \_/

Copy the non-circular band diagram.

Idea: recursively traverse each vertex according to the depth search, and the result is a sub-graph that returns the starting point at the critical point. To consider the case with a loop, but also to avoid the same node access multiple times, the map can be used to judge the weight.

 Static class Undirectedgraphnode {int label;        List<undirectedgraphnode> Neighbors;            Undirectedgraphnode (int x) {label = x;        Neighbors = new Arraylist<undirectedgraphnode> ();        }} static public Undirectedgraphnode Dfs (undirectedgraphnode node, Map<integer, undirectedgraphnode> Vis) { if (node! = null && vis.get (node.label) = = null) {Undirectedgraphnode CloneNode = new undirected            Graphnode (Node.label);            Vis.put (Node.label, CloneNode);            Clonenode.neighbors = new Arraylist<undirectedgraphnode> (Node.neighbors.size ()); for (int i = 0; i < node.neighbors.size (); i++) {CloneNode.neighbors.add (Dfs (Node.neighbors.get (i), Vis            ));        } return CloneNode;        } else if (node = = null) {return node;        } else {//deal If the graph has a circle return Vis.get (Node.label); }} STATic public undirectedgraphnode Clonegraph (Undirectedgraphnode node) {Map<integer, undirectedgraphnode> vis =        New Hashmap<integer, undirectedgraphnode> ();    Return DFS (node, VIS);        } public static void Main (string[] args) {undirectedgraphnode node = new Undirectedgraphnode (0);        Node.neighbors.add (node);        System.out.println (node.neighbors.get (0) = = node);        Undirectedgraphnode clone = clonegraph (node);    System.out.println (Clone.label); }

Copy the non-circular band diagram