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CloneGraph.java
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CloneGraph.java
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/*
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
/ \
\_/
*/
//DFS
public class Solution {
public UndirectedGraphNode cloneGraph(UndirectedGraphNode node) {
if (node == null) {
return node;
}
Map<Integer, UndirectedGraphNode> cloneNodeMap = new HashMap<>();
UndirectedGraphNode cloneNode = cloneGraphCore(node, cloneNodeMap);
return cloneNode;
}
public UndirectedGraphNode cloneGraphCore(UndirectedGraphNode node, Map<Integer, UndirectedGraphNode> cloneNodeMap) {
UndirectedGraphNode newNode = new UndirectedGraphNode(node.label);
cloneNodeMap.put(node.label, newNode);
List<UndirectedGraphNode> newNeighborNodes = new ArrayList<>();
for (UndirectedGraphNode neighborNode : node.neighbors) {
if (cloneNodeMap.containsKey(neighborNode.label)) {
newNeighborNodes.add(cloneNodeMap.get(neighborNode.label));
}
else {
UndirectedGraphNode newNeighbor = cloneGraphCore(neighborNode, cloneNodeMap);
newNeighborNodes.add(newNeighbor);
}
}
newNode.neighbors = newNeighborNodes;
return newNode;
}
}
//BFS
public class Solution {
public UndirectedGraphNode cloneGraph(UndirectedGraphNode node) {
if (node == null) {
return node;
}
Map<Integer, UndirectedGraphNode> cloneNodeMap = new HashMap<>();
UndirectedGraphNode cloneNode = cloneGraphCore(node, cloneNodeMap);
return cloneNode;
}
public UndirectedGraphNode cloneGraphCore(UndirectedGraphNode node, Map<Integer, UndirectedGraphNode> cloneNodeMap) {
UndirectedGraphNode newNode = new UndirectedGraphNode(node.label);
cloneNodeMap.put(node.label, newNode);
Queue<UndirectedGraphNode> queueNodes = new LinkedList<>();
queueNodes.offer(node);
while (queueNodes.size() > 0) {
UndirectedGraphNode topNode = queueNodes.poll();
UndirectedGraphNode newCloneNode = cloneNodeMap.get(topNode.label);
List<UndirectedGraphNode> newNeighborNodes = new ArrayList<>();
for (UndirectedGraphNode neighborNode : topNode.neighbors) {
if (cloneNodeMap.containsKey(neighborNode.label)) {
newNeighborNodes.add(cloneNodeMap.get(neighborNode.label));
}
else {
UndirectedGraphNode newNeighborCloneNode = new UndirectedGraphNode(neighborNode.label);
cloneNodeMap.put(neighborNode.label, newNeighborCloneNode);
newNeighborNodes.add(newNeighborCloneNode);
queueNodes.offer(neighborNode);
}
}
newCloneNode.neighbors = newNeighborNodes;
}
return newNode;
}
}