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  1. #include <bits/stdc++.h>
  2. #define ll long long
  3.  
  4. using namespace std;
  5.  
  6. const int MOD = 1e9 + 7;
  7.  
  8. void solve(){
  9. 	int n, k;
  10. 	cin >> n >> k;
  11.  
  12. 	vector<vector<int>> g(n, vector<int>());
  13.  
  14. 	for(int i = 1; i < n; i++){
  15. 		int x;
  16. 		cin>> x;
  17. 		x--;
  18. 		g[i].push_back(x);
  19. 		g[x].push_back(i);
  20. 	}
  21.  
  22. 	int s = 1, e = n - 1;
  23. 	int ans = n - 1;
  24. 	int cnt = 0;
  25. 	auto dfs = [&](int x, int par, int m, auto && self) -> int {
  26. 		int h = 1;
  27. 		for(auto y: g[x]){
  28. 			if(y != par){
  29. 				h = max(h, self(y, x, m, self) + 1);
  30. 			}
  31. 		}
  32. 		if(x == 0)return 0;
  33. 		if(h == m && par != 0){
  34. 			cnt++;
  35. 			return 0;
  36. 		}else{
  37. 			return h;
  38. 		}
  39. 	};
  40. 	while(s <= e){
  41. 		int mid = s + (e - s) / 2;
  42. 		cnt = 0;
  43. 		dfs(0, -1, mid, dfs);
  44. 		if(cnt <= k){
  45. 			ans = mid;
  46. 			e = mid - 1;
  47. 		}else{
  48. 			s = mid + 1;
  49. 		}
  50. 	}
  51. 	cout << ans << "\n";
  52.  
  53. }
  54.  
  55. int main(){
  56. 	ios_base::sync_with_stdio(false);
  57. 	cin.tie(nullptr);
  58.  
  59. 	int t = 1;
  60. 	cin >> t;
  61.  
  62. 	for(int i = 1; i <= t; i++){
  63. 		solve();
  64. 	}
  65. 	return 0;
  66. }
Success #stdin #stdout 0.01s 5296KB
comments (?)
stdin
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5
5 1
1 1 2 2
5 2
1 1 2 2
6 0
1 2 3 4 5
6 1
1 2 3 4 5
4 3
1 1 1
stdout
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2
1
5
3
1
https://ideone.com/3Xh8D9
language:
C++14 (gcc 8.3)
created:
12 days ago
visibility:
public

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