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Submission #30481

# Submission time Handle Problem Language Result Execution time Memory
30481 2017-07-23T19:07:35 Z sampriti Network (BOI15_net) C++14
63 / 100
 439 ms 32100 KB 
#include <iostream>
#include <algorithm>
#include <vector>
#include <cassert>

using namespace std;

vector<int> G[500001];
vector<int> leaves;

void dfs(int i, int p) {
  if(G[i].size() == 1) leaves.push_back(i);

  for(int j = 0; j < G[i].size(); j++) {
    int u = G[i][j];
    if(u == p) continue;
    dfs(u, i);
  }
}

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

  int N; cin >> N;

  for(int i = 0; i < N - 1; i++) {
    int a, b; cin >> a >> b;
    G[a].push_back(b);
    G[b].push_back(a);
  }

  dfs(1, 0);

  int ans = (leaves.size() + 1)/2;

  cout << ans << endl;

  for(int i = 0; i < ans; i++) {
    assert((i + leaves.size()/2) < leaves.size());
    cout << leaves[i] << " " << leaves[i + leaves.size()/2] << endl;
  }
}

Compilation message

net.cpp: In function 'void dfs(int, int)':
net.cpp:14:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int j = 0; j < G[i].size(); j++) {
                    ^

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 13896 KB Output is correct
2 Correct 3 ms 13896 KB Output is correct
3 Correct 0 ms 13896 KB Output is correct
4 Correct 0 ms 13896 KB Output is correct
5 Correct 3 ms 13896 KB Output is correct
6 Correct 0 ms 13896 KB Output is correct
7 Correct 6 ms 13896 KB Output is correct
8 Correct 3 ms 13896 KB Output is correct
9 Correct 3 ms 13896 KB Output is correct
10 Correct 0 ms 13896 KB Output is correct
11 Correct 3 ms 13896 KB Output is correct
12 Correct 0 ms 13896 KB Output is correct
13 Correct 6 ms 13896 KB Output is correct
14 Correct 3 ms 13896 KB Output is correct
15 Correct 0 ms 13896 KB Output is correct
16 Correct 3 ms 13896 KB Output is correct
17 Correct 3 ms 13896 KB Output is correct
18 Correct 3 ms 13896 KB Output is correct
19 Correct 0 ms 13896 KB Output is correct
20 Correct 3 ms 13896 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 13896 KB Output is correct
2 Correct 3 ms 13896 KB Output is correct
3 Correct 0 ms 13896 KB Output is correct
4 Correct 0 ms 13896 KB Output is correct
5 Correct 3 ms 13896 KB Output is correct
6 Correct 0 ms 13896 KB Output is correct
7 Correct 6 ms 13896 KB Output is correct
8 Correct 3 ms 13896 KB Output is correct
9 Correct 3 ms 13896 KB Output is correct
10 Correct 0 ms 13896 KB Output is correct
11 Correct 3 ms 13896 KB Output is correct
12 Correct 0 ms 13896 KB Output is correct
13 Correct 6 ms 13896 KB Output is correct
14 Correct 3 ms 13896 KB Output is correct
15 Correct 0 ms 13896 KB Output is correct
16 Correct 3 ms 13896 KB Output is correct
17 Correct 3 ms 13896 KB Output is correct
18 Correct 3 ms 13896 KB Output is correct
19 Correct 0 ms 13896 KB Output is correct
20 Correct 3 ms 13896 KB Output is correct
21 Correct 0 ms 13896 KB Output is correct
22 Correct 6 ms 13896 KB Output is correct
23 Correct 6 ms 13896 KB Output is correct
24 Correct 6 ms 13896 KB Output is correct
25 Correct 6 ms 13896 KB Output is correct
26 Correct 3 ms 13896 KB Output is correct
27 Correct 6 ms 13896 KB Output is correct
28 Correct 13 ms 13896 KB Output is correct
29 Correct 6 ms 13896 KB Output is correct
30 Correct 0 ms 13896 KB Output is correct
31 Correct 3 ms 13896 KB Output is correct
32 Correct 0 ms 13896 KB Output is correct
33 Correct 0 ms 13896 KB Output is correct
34 Correct 3 ms 13896 KB Output is correct
35 Correct 3 ms 13896 KB Output is correct
36 Correct 0 ms 13896 KB Output is correct
37 Correct 0 ms 13896 KB Output is correct
38 Correct 0 ms 13896 KB Output is correct
39 Correct 3 ms 13896 KB Output is correct
40 Correct 6 ms 13896 KB Output is correct
41 Correct 0 ms 13896 KB Output is correct
42 Correct 3 ms 13896 KB Output is correct
43 Correct 3 ms 13896 KB Output is correct
44 Correct 3 ms 13896 KB Output is correct
45 Correct 3 ms 13896 KB Output is correct
46 Correct 9 ms 13896 KB Output is correct
47 Correct 3 ms 13896 KB Output is correct
48 Correct 3 ms 13896 KB Output is correct
49 Correct 3 ms 13896 KB Output is correct
50 Correct 9 ms 13896 KB Output is correct
51 Correct 3 ms 13896 KB Output is correct
52 Correct 3 ms 13896 KB Output is correct
53 Correct 0 ms 13896 KB Output is correct
54 Correct 3 ms 13896 KB Output is correct
55 Correct 3 ms 13896 KB Output is correct
56 Correct 0 ms 13896 KB Output is correct
57 Correct 3 ms 13896 KB Output is correct
58 Correct 9 ms 13896 KB Output is correct

Subtask #3
0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 13896 KB Output is correct
2 Correct 3 ms 13896 KB Output is correct
3 Correct 0 ms 13896 KB Output is correct
4 Correct 0 ms 13896 KB Output is correct
5 Correct 3 ms 13896 KB Output is correct
6 Correct 0 ms 13896 KB Output is correct
7 Correct 6 ms 13896 KB Output is correct
8 Correct 3 ms 13896 KB Output is correct
9 Correct 3 ms 13896 KB Output is correct
10 Correct 0 ms 13896 KB Output is correct
11 Correct 3 ms 13896 KB Output is correct
12 Correct 0 ms 13896 KB Output is correct
13 Correct 6 ms 13896 KB Output is correct
14 Correct 3 ms 13896 KB Output is correct
15 Correct 0 ms 13896 KB Output is correct
16 Correct 3 ms 13896 KB Output is correct
17 Correct 3 ms 13896 KB Output is correct
18 Correct 3 ms 13896 KB Output is correct
19 Correct 0 ms 13896 KB Output is correct
20 Correct 3 ms 13896 KB Output is correct
21 Correct 0 ms 13896 KB Output is correct
22 Correct 6 ms 13896 KB Output is correct
23 Correct 6 ms 13896 KB Output is correct
24 Correct 6 ms 13896 KB Output is correct
25 Correct 6 ms 13896 KB Output is correct
26 Correct 3 ms 13896 KB Output is correct
27 Correct 6 ms 13896 KB Output is correct
28 Correct 13 ms 13896 KB Output is correct
29 Correct 6 ms 13896 KB Output is correct
30 Correct 0 ms 13896 KB Output is correct
31 Correct 3 ms 13896 KB Output is correct
32 Correct 0 ms 13896 KB Output is correct
33 Correct 0 ms 13896 KB Output is correct
34 Correct 3 ms 13896 KB Output is correct
35 Correct 3 ms 13896 KB Output is correct
36 Correct 0 ms 13896 KB Output is correct
37 Correct 0 ms 13896 KB Output is correct
38 Correct 0 ms 13896 KB Output is correct
39 Correct 3 ms 13896 KB Output is correct
40 Correct 6 ms 13896 KB Output is correct
41 Correct 0 ms 13896 KB Output is correct
42 Correct 3 ms 13896 KB Output is correct
43 Correct 3 ms 13896 KB Output is correct
44 Correct 3 ms 13896 KB Output is correct
45 Correct 3 ms 13896 KB Output is correct
46 Correct 9 ms 13896 KB Output is correct
47 Correct 3 ms 13896 KB Output is correct
48 Correct 3 ms 13896 KB Output is correct
49 Correct 3 ms 13896 KB Output is correct
50 Correct 9 ms 13896 KB Output is correct
51 Correct 3 ms 13896 KB Output is correct
52 Correct 3 ms 13896 KB Output is correct
53 Correct 0 ms 13896 KB Output is correct
54 Correct 3 ms 13896 KB Output is correct
55 Correct 3 ms 13896 KB Output is correct
56 Correct 0 ms 13896 KB Output is correct
57 Correct 3 ms 13896 KB Output is correct
58 Correct 9 ms 13896 KB Output is correct
59 Runtime error 439 ms 32100 KB Execution timed out (wall clock limit exceeded)
60 Halted 0 ms 0 KB -