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 / \ \_/ package com.graph; import java.util.*; //Definition for undirected graph. class UndirectedGraphNode { int label; List<UndirectedGraphNode> neighbors; UndirectedGraphNode(int x) { label = x; neighbors = new ArrayList<UndirectedGraphNode>(); } }; public class M133_Clone_Graph { public UndirectedGraphNode cloneGraph(UndirectedGraphNode node) { Queue<UndirectedGraphNode> Q = new LinkedList<UndirectedGraphNode>(); Map<Integer, UndirectedGraphNode> map = new HashMap<Integer, UndirectedGraphNode>(); if(node == null) return null; Q.add(node); UndirectedGraphNode newNode = new UndirectedGraphNode(node.label); map.put(newNode.label, newNode); while(!Q.isEmpty()) { UndirectedGraphNode t = Q.poll(); UndirectedGraphNode tt = map.get(t.label); for(UndirectedGraphNode adj:t.neighbors) { UndirectedGraphNode newAdj = null; if(map.containsKey(adj.label)) { newAdj = map.get(adj.label); }else { newAdj = new UndirectedGraphNode(adj.label); map.put(newAdj.label, newAdj); //Revise Q.add(adj); } tt.neighbors.add(newAdj); //Error //Q.add(adj); } } return newNode; } }
