Clone an undirected graph. Each node in the graph contains a label and a list of its neighbors.
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 #.
0. Connect node 0 to
both nodes 1 and 2.1. Connect node 1 to
node 2.2. Connect node 2 to
node 2 (itself), thus forming a self-cycle.Visually, the graph looks like the following:
1
/ / 0 --- 2
/ \_/
利用递归深搜，同时用一个map存储已经 new 过的node，如果已经new 过则直接返回存在map里的节点
/**
* Definition for undirected graph.
* class UndirectedGraphNode {
* int label;
* List<UndirectedGraphNode> neighbors;
* UndirectedGraphNode(int x) { label = x; neighbors = new ArrayList<UndirectedGraphNode>(); }
* };
*/
public class Solution {
Map<UndirectedGraphNode,UndirectedGraphNode> map = new HashMap<>();
public UndirectedGraphNode cloneGraph(UndirectedGraphNode node) {
if (node == null)
return null;
if(map.containsKey(node)){
return map.get(node);
}
UndirectedGraphNode ug = new UndirectedGraphNode(node.label);
map.put(node, ug);
for (int i = 0; i < node.neighbors.size(); i++) {
ug.neighbors.add(cloneGraph(node.neighbors.get(i)));
}
return ug;
}
}
原文：http://blog.csdn.net/guorudi/article/details/42127337