Codeforces Round #321 (Div. 2) 580C. Kefa and Park Solution

 Problem Link: https://codeforces.com/problemset/problem/580/C

Solution in C++:

1. /// La ilaha illellahu muhammadur rasulullah
2. ///******Bismillahir-Rahmanir-Rahim******///
3. /// Abul Hasnat Tonmoy
4. /// Department of CSE,23rd batch
5. /// Islamic University,Bangladesh
6. ///**********ALLAH IS ALMIGHTY************///
7. #include <bits/stdc++.h>
8. using namespace std;
9. const int N = 1e5 + 9;
10. std::vector<int> adj[N];
11. int vis[N], ar[N], ans = 0, cnt = 0, m;
12. void dfs(int n, int cnt) {
13. vis[n] = 1;
14. if (ar[n] == 1)
15. cnt++;
16. else if (ar[n] == 0 && cnt <= m)
17. cnt = 0;
18. if (adj[n].size() == 1 && cnt <= m && n != 1) ans++;
19. for (auto v : adj[n]) {
20. if (!vis[v]) dfs(v, cnt);
21. }
22. }
23. int main() {
24. ios_base::sync_with_stdio(0);
25. cin.tie(0);
26. int n, cnt = 0;
27. cin >> n >> m;
28. for (int i = 1; i <= n; i++) cin >> ar[i];
29. int t;
30. t = n - 1;
31. while (t--) {
32. int u, v;
33. cin >> u >> v;
34. adj[u].push_back(v);
35. adj[v].push_back(u);
36. }
37. dfs(1, cnt);
38. cout << ans << endl;
39. }