leetcode

0 class Solution {

1 public:

2 Node *cloneGraph(Node *node) {

3 if (!node) return nullptr;

4

5 Node *head = new Node(node->val);

6 unordered_map<Node *, Node *> um({{node, head}});

7

8 stack<Node *> st;

9 st.push(node);

10 while (!st.empty()) {

11 Node *node = st.top();

12 st.pop();

13 for (Node *c : node->neighbors) {

14 if (um.find(c) != um.end()) {

15 um[node]->neighbors.push_back(um[c]);

16 continue;

17 }

18 Node *n = new Node(c->val);

19 um[node]->neighbors.push_back(n);

20 um.insert(make_pair(c, n));

21 st.push(c);

22 }

23 }

24 return head;

25 }

26 };