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Submission #231016

# Submission time Handle Problem Language Result Execution time Memory
231016 2020-05-12T10:53:45 Z AlexLuchianov Network (BOI15_net) C++14
100 / 100
 529 ms 57852 KB 
#include <iostream>
#include <vector>
#include <algorithm>
#include <cassert>
#include <cmath>

using namespace std;

using ll = long long;
#define MIN(a, b) (((a) < (b)) ? (a) : (b))
#define MAX(a, b) (((a) < (b)) ? (b) : (a))

int const nmax = 500000;
vector<int> g[1 + nmax];

vector<int> sol;

void dfs(int node, int parent){
  for(int h = 0; h < g[node].size(); h++){
    int to = g[node][h];
    if(to != parent)
      dfs(to, node);
  }
  if(g[node].size() == 1)
    sol.push_back(node);
}

int main()
{
  ios::sync_with_stdio(0);
  cin.tie(0);

  int n;
  cin >> n;
  for(int i = 1;i < n; i++){
    int x, y;
    cin >> x >> y;
    g[x].push_back(y);
    g[y].push_back(x);
  }
  int root = 1;
  for(int i = 1;i <= n; i++)
    if(1 < g[i].size())
      root = i;
  dfs(root, 0);
  cout << (sol.size() + 1) / 2 << '\n';

  int d = sol.size() / 2;

  if(sol.size() % 2 == 1)
    cout << sol[d] << " " << root << '\n';

  for(int i = 0; i < d; i++)
    cout << sol[i] << " " << sol[i + d + sol.size() % 2] << '\n';

  return 0;
}

Compilation message

net.cpp: In function 'void dfs(int, int)':
net.cpp:19:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int h = 0; h < g[node].size(); h++){
                  ~~^~~~~~~~~~~~~~~~

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 12032 KB Output is correct
2 Correct 13 ms 12032 KB Output is correct
3 Correct 11 ms 12160 KB Output is correct
4 Correct 11 ms 12032 KB Output is correct
5 Correct 11 ms 12032 KB Output is correct
6 Correct 12 ms 12032 KB Output is correct
7 Correct 13 ms 12160 KB Output is correct
8 Correct 11 ms 12160 KB Output is correct
9 Correct 12 ms 12160 KB Output is correct
10 Correct 11 ms 12032 KB Output is correct
11 Correct 12 ms 12160 KB Output is correct
12 Correct 11 ms 12032 KB Output is correct
13 Correct 12 ms 12160 KB Output is correct
14 Correct 11 ms 12032 KB Output is correct
15 Correct 11 ms 12160 KB Output is correct
16 Correct 11 ms 12032 KB Output is correct
17 Correct 11 ms 12032 KB Output is correct
18 Correct 13 ms 12032 KB Output is correct
19 Correct 11 ms 12160 KB Output is correct
20 Correct 11 ms 12160 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 12032 KB Output is correct
2 Correct 13 ms 12032 KB Output is correct
3 Correct 11 ms 12160 KB Output is correct
4 Correct 11 ms 12032 KB Output is correct
5 Correct 11 ms 12032 KB Output is correct
6 Correct 12 ms 12032 KB Output is correct
7 Correct 13 ms 12160 KB Output is correct
8 Correct 11 ms 12160 KB Output is correct
9 Correct 12 ms 12160 KB Output is correct
10 Correct 11 ms 12032 KB Output is correct
11 Correct 12 ms 12160 KB Output is correct
12 Correct 11 ms 12032 KB Output is correct
13 Correct 12 ms 12160 KB Output is correct
14 Correct 11 ms 12032 KB Output is correct
15 Correct 11 ms 12160 KB Output is correct
16 Correct 11 ms 12032 KB Output is correct
17 Correct 11 ms 12032 KB Output is correct
18 Correct 13 ms 12032 KB Output is correct
19 Correct 11 ms 12160 KB Output is correct
20 Correct 11 ms 12160 KB Output is correct
21 Correct 11 ms 12032 KB Output is correct
22 Correct 12 ms 12160 KB Output is correct
23 Correct 12 ms 12160 KB Output is correct
24 Correct 12 ms 12160 KB Output is correct
25 Correct 13 ms 12160 KB Output is correct
26 Correct 15 ms 12160 KB Output is correct
27 Correct 12 ms 12288 KB Output is correct
28 Correct 12 ms 12160 KB Output is correct
29 Correct 13 ms 12288 KB Output is correct
30 Correct 11 ms 12032 KB Output is correct
31 Correct 13 ms 12160 KB Output is correct
32 Correct 11 ms 12160 KB Output is correct
33 Correct 11 ms 12032 KB Output is correct
34 Correct 11 ms 12160 KB Output is correct
35 Correct 12 ms 12160 KB Output is correct
36 Correct 11 ms 12160 KB Output is correct
37 Correct 12 ms 12160 KB Output is correct
38 Correct 13 ms 12160 KB Output is correct
39 Correct 12 ms 12032 KB Output is correct
40 Correct 11 ms 12032 KB Output is correct
41 Correct 12 ms 12160 KB Output is correct
42 Correct 11 ms 12160 KB Output is correct
43 Correct 12 ms 12160 KB Output is correct
44 Correct 11 ms 12032 KB Output is correct
45 Correct 11 ms 12160 KB Output is correct
46 Correct 12 ms 12160 KB Output is correct
47 Correct 12 ms 12160 KB Output is correct
48 Correct 12 ms 12032 KB Output is correct
49 Correct 12 ms 12160 KB Output is correct
50 Correct 11 ms 12032 KB Output is correct
51 Correct 11 ms 12032 KB Output is correct
52 Correct 11 ms 12160 KB Output is correct
53 Correct 12 ms 12160 KB Output is correct
54 Correct 11 ms 12032 KB Output is correct
55 Correct 12 ms 12032 KB Output is correct
56 Correct 11 ms 12032 KB Output is correct
57 Correct 12 ms 12160 KB Output is correct
58 Correct 12 ms 12160 KB Output is correct

Subtask #3
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 12032 KB Output is correct
2 Correct 13 ms 12032 KB Output is correct
3 Correct 11 ms 12160 KB Output is correct
4 Correct 11 ms 12032 KB Output is correct
5 Correct 11 ms 12032 KB Output is correct
6 Correct 12 ms 12032 KB Output is correct
7 Correct 13 ms 12160 KB Output is correct
8 Correct 11 ms 12160 KB Output is correct
9 Correct 12 ms 12160 KB Output is correct
10 Correct 11 ms 12032 KB Output is correct
11 Correct 12 ms 12160 KB Output is correct
12 Correct 11 ms 12032 KB Output is correct
13 Correct 12 ms 12160 KB Output is correct
14 Correct 11 ms 12032 KB Output is correct
15 Correct 11 ms 12160 KB Output is correct
16 Correct 11 ms 12032 KB Output is correct
17 Correct 11 ms 12032 KB Output is correct
18 Correct 13 ms 12032 KB Output is correct
19 Correct 11 ms 12160 KB Output is correct
20 Correct 11 ms 12160 KB Output is correct
21 Correct 11 ms 12032 KB Output is correct
22 Correct 12 ms 12160 KB Output is correct
23 Correct 12 ms 12160 KB Output is correct
24 Correct 12 ms 12160 KB Output is correct
25 Correct 13 ms 12160 KB Output is correct
26 Correct 15 ms 12160 KB Output is correct
27 Correct 12 ms 12288 KB Output is correct
28 Correct 12 ms 12160 KB Output is correct
29 Correct 13 ms 12288 KB Output is correct
30 Correct 11 ms 12032 KB Output is correct
31 Correct 13 ms 12160 KB Output is correct
32 Correct 11 ms 12160 KB Output is correct
33 Correct 11 ms 12032 KB Output is correct
34 Correct 11 ms 12160 KB Output is correct
35 Correct 12 ms 12160 KB Output is correct
36 Correct 11 ms 12160 KB Output is correct
37 Correct 12 ms 12160 KB Output is correct
38 Correct 13 ms 12160 KB Output is correct
39 Correct 12 ms 12032 KB Output is correct
40 Correct 11 ms 12032 KB Output is correct
41 Correct 12 ms 12160 KB Output is correct
42 Correct 11 ms 12160 KB Output is correct
43 Correct 12 ms 12160 KB Output is correct
44 Correct 11 ms 12032 KB Output is correct
45 Correct 11 ms 12160 KB Output is correct
46 Correct 12 ms 12160 KB Output is correct
47 Correct 12 ms 12160 KB Output is correct
48 Correct 12 ms 12032 KB Output is correct
49 Correct 12 ms 12160 KB Output is correct
50 Correct 11 ms 12032 KB Output is correct
51 Correct 11 ms 12032 KB Output is correct
52 Correct 11 ms 12160 KB Output is correct
53 Correct 12 ms 12160 KB Output is correct
54 Correct 11 ms 12032 KB Output is correct
55 Correct 12 ms 12032 KB Output is correct
56 Correct 11 ms 12032 KB Output is correct
57 Correct 12 ms 12160 KB Output is correct
58 Correct 12 ms 12160 KB Output is correct
59 Correct 367 ms 36068 KB Output is correct
60 Correct 463 ms 38828 KB Output is correct
61 Correct 12 ms 12032 KB Output is correct
62 Correct 11 ms 12032 KB Output is correct
63 Correct 316 ms 33764 KB Output is correct
64 Correct 14 ms 12416 KB Output is correct
65 Correct 24 ms 13824 KB Output is correct
66 Correct 168 ms 25208 KB Output is correct
67 Correct 529 ms 57852 KB Output is correct
68 Correct 517 ms 50800 KB Output is correct
69 Correct 19 ms 12928 KB Output is correct
70 Correct 100 ms 21356 KB Output is correct
71 Correct 329 ms 42096 KB Output is correct
72 Correct 325 ms 40676 KB Output is correct
73 Correct 95 ms 19188 KB Output is correct
74 Correct 444 ms 37736 KB Output is correct
75 Correct 37 ms 15352 KB Output is correct
76 Correct 336 ms 41652 KB Output is correct
77 Correct 309 ms 41684 KB Output is correct
78 Correct 37 ms 15480 KB Output is correct
79 Correct 520 ms 45096 KB Output is correct
80 Correct 13 ms 12288 KB Output is correct
81 Correct 126 ms 21572 KB Output is correct
82 Correct 395 ms 39652 KB Output is correct
83 Correct 451 ms 37864 KB Output is correct
84 Correct 465 ms 37740 KB Output is correct
85 Correct 459 ms 37736 KB Output is correct
86 Correct 460 ms 38892 KB Output is correct
87 Correct 451 ms 38760 KB Output is correct