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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
/ \_/
复制无向带环图。
思路：按照深度搜索递归遍历每个顶点，遍历结果是返回以临界点为起始点的子图。要考虑带环的情况，又要避免同一节点访问多次，可用map来判重。
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 UndirectedGraphNode(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);
}标签：
原文地址：http://blog.csdn.net/wongson/article/details/45027491
