leetcode

0 class Solution {

1 public:

2 vector<vector<int>> getAncestors(int n, vector<vector<int>> &edges) {

3 vector<vector<int>> adj(n, vector<int>());

4 vector<vector<int>> anc(n, vector<int>());

5

6 for (auto &p : edges)

7 adj[p[0]].push_back(p[1]);

8 for (int i = 0; i < n; i++) {

9 stack<int> st;

10 st.push(i);

11 while (!st.empty()) {

12 int root = st.top();

13 st.pop();

14 for (int c : adj[root]) {

15 if (!anc[c].empty() && anc[c].back() == i) continue;

16 anc[c].push_back(i);

17 st.push(c);

18 }

19 }

20 }

21

22 return anc;

23 }

24 };