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| class Solution {
public Node cloneGraph(Node node) {
if (node == null) {
return null;
}
Map<Node, Node> originalToCloneNodeMap = new IdentityHashMap<>();
return cloneNode(node, originalToCloneNodeMap);
}
private List<Node> cloneNeighbors(List<Node> neighbors, Map<Node, Node> originalToCloneNodeMap) {
if (neighbors.isEmpty()) {
return Collections.emptyList();
}
List<Node> cloneNeighbors = new ArrayList<>(neighbors.size());
for (Node node : neighbors) {
cloneNeighbors.add(cloneNode(node, originalToCloneNodeMap));
}
return cloneNeighbors;
}
private Node cloneNode(Node node, Map<Node, Node> originalToCloneNodeMap) {
Node cloneNode = originalToCloneNodeMap.get(node);
if (cloneNode != null) {
return cloneNode;
}
cloneNode = new Node(node.val);
originalToCloneNodeMap.put(node, cloneNode);
cloneNode.neighbors = cloneNeighbors(node.neighbors, originalToCloneNodeMap);
return cloneNode;
}
}
|