fork download
copy 
  1. #include<bits/stdc++.h>
  2. using namespace std;
  3.  
  4. #define fastio ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)
  5. #define MOD 1000000007
  6. #define ll long long int
  7.  
  8. const int N = 10005;
  9. vector<int> adj[N], vis(N);
  10. int maxD, maxNode;
  11. void dfs(int root, int d) {
  12. 	vis[root] = 1;
  13. 	if(d > maxD) {
  14. 		maxD = d;
  15. 		maxNode = root;
  16. 	}
  17. 	for(auto child : adj[root]) {
  18. 		if(!vis[child])
  19. 			dfs(child, d + 1);
  20. 	}
  21. }
  22.  
  23. int main() {
  24.  
  25. 	fastio;
  26.  
  27. 	int n;
  28. 	cin >> n;
  29.  
  30. 	for(int i = 0; i < n - 1; i++) {
  31. 		int u, v;
  32. 		cin >> u >> v;
  33. 		adj[u].push_back(v);
  34. 		adj[v].push_back(u);
  35. 	}
  36.  
  37. 	dfs(1, 0);
  38. 	maxD = 0;
  39. 	for(int i = 0; i < n + 1; i++) vis[i] = 0;
  40. 	dfs(maxNode, 0);
  41. 	cout << maxD;
  42.  
  43. 	return 0;
  44. }
  45.  
Success #stdin #stdout 0s 5628KB
comments (?)
stdin
copy 
3
1 2
2 3
stdout
copy 
2
https://ideone.com/1ak2ic
language:
C++14 (gcc 8.3)
created:
4 years ago
visibility:
secret

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!