/* // Definition for a Node. class Node { public: int val; vector<Node*> neighbors; Node() { val = 0; neighbors = vector<Node*>(); } Node(int _val) { val = _val; neighbors = vector<Node*>(); } Node(int _val, vector<Node*> _neighbors) { val = _val; neighbors = _neighbors; } }; */ class Solution { public: Node* cloneGraph(Node* node) { if (!node) return nullptr; queue<Node*> q{{node}}; unordered_map<Node*, Node*> map{{node, new Node(node->val)}}; while (!q.empty()) { Node* u = q.front(); q.pop(); for (Node* v : u->neighbors) { if (!map.count(v)) { map[v] = new Node(v->val); q.push(v); } map[u]->neighbors.push_back(map[v]); } } return map[node]; } };