Method cloneGraph

133-clone-graph/clone-graph.java:23–28

(Node node)

class Solution {
    public Node cloneGraph(Node node) {
        if (node == null) return null;
        
        Map<Node, Node> visited = new HashMap<>();
        return dfs(node, visited);
    }
    
    private Node dfs(Node node, Map<Node, Node> visited) {
        if (visited.containsKey(node)) return visited.get(node);