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Submission #30484

# Submission time Handle Problem Language Result Execution time Memory
30484 2017-07-23T19:59:22 Z sampriti Network (BOI15_net) C++14
100 / 100
 783 ms 41660 KB 
#include <cstdio>
#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() {
  int N; scanf("%d", &N);

  for(int i = 0; i < N - 1; i++) {
    int a, b; scanf("%d %d", &a, &b);
    G[a].push_back(b);
    G[b].push_back(a);
  }

  dfs(1, 0);

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

  printf("%d\n", ans);

  for(int i = 0; i < ans; i++) {
    assert((i + leaves.size()/2) < leaves.size());
    printf("%d %d\n", leaves[i], leaves[i + leaves.size()/2]);
  }
}

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++) {
                    ^
net.cpp: In function 'int main()':
net.cpp:22:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   int N; scanf("%d", &N);
                         ^
net.cpp:25:37: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     int a, b; scanf("%d %d", &a, &b);
                                     ^

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 12888 KB Output is correct
2 Correct 3 ms 12888 KB Output is correct
3 Correct 0 ms 12888 KB Output is correct
4 Correct 3 ms 12888 KB Output is correct
5 Correct 3 ms 12888 KB Output is correct
6 Correct 3 ms 12888 KB Output is correct
7 Correct 0 ms 12888 KB Output is correct
8 Correct 0 ms 12888 KB Output is correct
9 Correct 3 ms 12888 KB Output is correct
10 Correct 3 ms 12888 KB Output is correct
11 Correct 0 ms 12888 KB Output is correct
12 Correct 3 ms 12888 KB Output is correct
13 Correct 3 ms 12888 KB Output is correct
14 Correct 3 ms 12888 KB Output is correct
15 Correct 3 ms 12888 KB Output is correct
16 Correct 3 ms 12888 KB Output is correct
17 Correct 3 ms 12888 KB Output is correct
18 Correct 3 ms 12888 KB Output is correct
19 Correct 3 ms 12888 KB Output is correct
20 Correct 0 ms 12888 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 12888 KB Output is correct
2 Correct 3 ms 12888 KB Output is correct
3 Correct 0 ms 12888 KB Output is correct
4 Correct 3 ms 12888 KB Output is correct
5 Correct 3 ms 12888 KB Output is correct
6 Correct 3 ms 12888 KB Output is correct
7 Correct 0 ms 12888 KB Output is correct
8 Correct 0 ms 12888 KB Output is correct
9 Correct 3 ms 12888 KB Output is correct
10 Correct 3 ms 12888 KB Output is correct
11 Correct 0 ms 12888 KB Output is correct
12 Correct 3 ms 12888 KB Output is correct
13 Correct 3 ms 12888 KB Output is correct
14 Correct 3 ms 12888 KB Output is correct
15 Correct 3 ms 12888 KB Output is correct
16 Correct 3 ms 12888 KB Output is correct
17 Correct 3 ms 12888 KB Output is correct
18 Correct 3 ms 12888 KB Output is correct
19 Correct 3 ms 12888 KB Output is correct
20 Correct 0 ms 12888 KB Output is correct
21 Correct 0 ms 12888 KB Output is correct
22 Correct 6 ms 13020 KB Output is correct
23 Correct 13 ms 13020 KB Output is correct
24 Correct 0 ms 13020 KB Output is correct
25 Correct 3 ms 13020 KB Output is correct
26 Correct 0 ms 13020 KB Output is correct
27 Correct 0 ms 13020 KB Output is correct
28 Correct 3 ms 13020 KB Output is correct
29 Correct 3 ms 13020 KB Output is correct
30 Correct 0 ms 12888 KB Output is correct
31 Correct 3 ms 13020 KB Output is correct
32 Correct 0 ms 12888 KB Output is correct
33 Correct 3 ms 12888 KB Output is correct
34 Correct 3 ms 12888 KB Output is correct
35 Correct 0 ms 12888 KB Output is correct
36 Correct 0 ms 12888 KB Output is correct
37 Correct 3 ms 12888 KB Output is correct
38 Correct 3 ms 12888 KB Output is correct
39 Correct 3 ms 12888 KB Output is correct
40 Correct 6 ms 12888 KB Output is correct
41 Correct 6 ms 12888 KB Output is correct
42 Correct 3 ms 12888 KB Output is correct
43 Correct 3 ms 12888 KB Output is correct
44 Correct 3 ms 12888 KB Output is correct
45 Correct 6 ms 12888 KB Output is correct
46 Correct 9 ms 12888 KB Output is correct
47 Correct 3 ms 12888 KB Output is correct
48 Correct 3 ms 12888 KB Output is correct
49 Correct 0 ms 12888 KB Output is correct
50 Correct 3 ms 12888 KB Output is correct
51 Correct 0 ms 12888 KB Output is correct
52 Correct 3 ms 12888 KB Output is correct
53 Correct 3 ms 12888 KB Output is correct
54 Correct 9 ms 12888 KB Output is correct
55 Correct 3 ms 12888 KB Output is correct
56 Correct 0 ms 12888 KB Output is correct
57 Correct 0 ms 12888 KB Output is correct
58 Correct 0 ms 13020 KB Output is correct

Subtask #3
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 12888 KB Output is correct
2 Correct 3 ms 12888 KB Output is correct
3 Correct 0 ms 12888 KB Output is correct
4 Correct 3 ms 12888 KB Output is correct
5 Correct 3 ms 12888 KB Output is correct
6 Correct 3 ms 12888 KB Output is correct
7 Correct 0 ms 12888 KB Output is correct
8 Correct 0 ms 12888 KB Output is correct
9 Correct 3 ms 12888 KB Output is correct
10 Correct 3 ms 12888 KB Output is correct
11 Correct 0 ms 12888 KB Output is correct
12 Correct 3 ms 12888 KB Output is correct
13 Correct 3 ms 12888 KB Output is correct
14 Correct 3 ms 12888 KB Output is correct
15 Correct 3 ms 12888 KB Output is correct
16 Correct 3 ms 12888 KB Output is correct
17 Correct 3 ms 12888 KB Output is correct
18 Correct 3 ms 12888 KB Output is correct
19 Correct 3 ms 12888 KB Output is correct
20 Correct 0 ms 12888 KB Output is correct
21 Correct 0 ms 12888 KB Output is correct
22 Correct 6 ms 13020 KB Output is correct
23 Correct 13 ms 13020 KB Output is correct
24 Correct 0 ms 13020 KB Output is correct
25 Correct 3 ms 13020 KB Output is correct
26 Correct 0 ms 13020 KB Output is correct
27 Correct 0 ms 13020 KB Output is correct
28 Correct 3 ms 13020 KB Output is correct
29 Correct 3 ms 13020 KB Output is correct
30 Correct 0 ms 12888 KB Output is correct
31 Correct 3 ms 13020 KB Output is correct
32 Correct 0 ms 12888 KB Output is correct
33 Correct 3 ms 12888 KB Output is correct
34 Correct 3 ms 12888 KB Output is correct
35 Correct 0 ms 12888 KB Output is correct
36 Correct 0 ms 12888 KB Output is correct
37 Correct 3 ms 12888 KB Output is correct
38 Correct 3 ms 12888 KB Output is correct
39 Correct 3 ms 12888 KB Output is correct
40 Correct 6 ms 12888 KB Output is correct
41 Correct 6 ms 12888 KB Output is correct
42 Correct 3 ms 12888 KB Output is correct
43 Correct 3 ms 12888 KB Output is correct
44 Correct 3 ms 12888 KB Output is correct
45 Correct 6 ms 12888 KB Output is correct
46 Correct 9 ms 12888 KB Output is correct
47 Correct 3 ms 12888 KB Output is correct
48 Correct 3 ms 12888 KB Output is correct
49 Correct 0 ms 12888 KB Output is correct
50 Correct 3 ms 12888 KB Output is correct
51 Correct 0 ms 12888 KB Output is correct
52 Correct 3 ms 12888 KB Output is correct
53 Correct 3 ms 12888 KB Output is correct
54 Correct 9 ms 12888 KB Output is correct
55 Correct 3 ms 12888 KB Output is correct
56 Correct 0 ms 12888 KB Output is correct
57 Correct 0 ms 12888 KB Output is correct
58 Correct 0 ms 13020 KB Output is correct
59 Correct 439 ms 31136 KB Output is correct
60 Correct 659 ms 32400 KB Output is correct
61 Correct 0 ms 12888 KB Output is correct
62 Correct 0 ms 12888 KB Output is correct
63 Correct 446 ms 29060 KB Output is correct
64 Correct 6 ms 13124 KB Output is correct
65 Correct 16 ms 14400 KB Output is correct
66 Correct 199 ms 26400 KB Output is correct
67 Correct 769 ms 40904 KB Output is correct
68 Correct 783 ms 41660 KB Output is correct
69 Correct 13 ms 13624 KB Output is correct
70 Correct 119 ms 21044 KB Output is correct
71 Correct 433 ms 34740 KB Output is correct
72 Correct 463 ms 34740 KB Output is correct
73 Correct 199 ms 18244 KB Output is correct
74 Correct 706 ms 30684 KB Output is correct
75 Correct 39 ms 15352 KB Output is correct
76 Correct 389 ms 33724 KB Output is correct
77 Correct 376 ms 33724 KB Output is correct
78 Correct 39 ms 15364 KB Output is correct
79 Correct 759 ms 39160 KB Output is correct
80 Correct 6 ms 13020 KB Output is correct
81 Correct 113 ms 19916 KB Output is correct
82 Correct 513 ms 32968 KB Output is correct
83 Correct 636 ms 30684 KB Output is correct
84 Correct 633 ms 30684 KB Output is correct
85 Correct 593 ms 30684 KB Output is correct
86 Correct 586 ms 32404 KB Output is correct
87 Correct 673 ms 32404 KB Output is correct