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Submission #394610

# Submission time Handle Problem Language Result Execution time Memory
394610 2021-04-27T05:49:15 Z Mahdi_Shokoufi Network (BOI15_net) C++17
100 / 100
 495 ms 58892 KB 
//In the name of Allah
#include <bits/stdc++.h>

using namespace std;

const int N = 5e5 + 5;

vector < int > adj[N], lf;

void DFS(int v, int p = 0){
    if (adj[v].size() == 1)
        lf.push_back(v);
    for (int u : adj[v])
        if (u != p)
            DFS(u, v);
}

int main(){
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    int n, r = 0;
    cin >> n;
    for (int i = 1; i < n; i ++){
        int u, v;
        cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    for (int i = 1; i <= n; i ++)
        if (adj[i].size() != 1)
            r = i;
    DFS(r);
    cout << (lf.size() + 1) / 2 << '\n';
    for (int i = 0; i < lf.size() / 2; i ++)
        cout << lf[i] << ' ' << lf[i + lf.size() / 2] << '\n';
    if (lf.size() & 1)
        cout << lf[0] << ' ' << lf.back() << '\n';
    return 0;
}

Compilation message

net.cpp: In function 'int main()':
net.cpp:34:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   34 |     for (int i = 0; i < lf.size() / 2; i ++)
      |                     ~~^~~~~~~~~~~~~~~

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 11980 KB Output is correct
2 Correct 8 ms 11980 KB Output is correct
3 Correct 8 ms 11980 KB Output is correct
4 Correct 8 ms 12056 KB Output is correct
5 Correct 8 ms 11980 KB Output is correct
6 Correct 8 ms 11980 KB Output is correct
7 Correct 8 ms 11980 KB Output is correct
8 Correct 8 ms 11968 KB Output is correct
9 Correct 8 ms 11980 KB Output is correct
10 Correct 8 ms 11980 KB Output is correct
11 Correct 8 ms 11980 KB Output is correct
12 Correct 8 ms 11980 KB Output is correct
13 Correct 8 ms 11980 KB Output is correct
14 Correct 8 ms 12036 KB Output is correct
15 Correct 8 ms 11980 KB Output is correct
16 Correct 8 ms 11980 KB Output is correct
17 Correct 8 ms 11980 KB Output is correct
18 Correct 8 ms 11984 KB Output is correct
19 Correct 8 ms 11972 KB Output is correct
20 Correct 8 ms 12056 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 11980 KB Output is correct
2 Correct 8 ms 11980 KB Output is correct
3 Correct 8 ms 11980 KB Output is correct
4 Correct 8 ms 12056 KB Output is correct
5 Correct 8 ms 11980 KB Output is correct
6 Correct 8 ms 11980 KB Output is correct
7 Correct 8 ms 11980 KB Output is correct
8 Correct 8 ms 11968 KB Output is correct
9 Correct 8 ms 11980 KB Output is correct
10 Correct 8 ms 11980 KB Output is correct
11 Correct 8 ms 11980 KB Output is correct
12 Correct 8 ms 11980 KB Output is correct
13 Correct 8 ms 11980 KB Output is correct
14 Correct 8 ms 12036 KB Output is correct
15 Correct 8 ms 11980 KB Output is correct
16 Correct 8 ms 11980 KB Output is correct
17 Correct 8 ms 11980 KB Output is correct
18 Correct 8 ms 11984 KB Output is correct
19 Correct 8 ms 11972 KB Output is correct
20 Correct 8 ms 12056 KB Output is correct
21 Correct 8 ms 11980 KB Output is correct
22 Correct 10 ms 12108 KB Output is correct
23 Correct 8 ms 12104 KB Output is correct
24 Correct 9 ms 12108 KB Output is correct
25 Correct 9 ms 12124 KB Output is correct
26 Correct 9 ms 12060 KB Output is correct
27 Correct 9 ms 12108 KB Output is correct
28 Correct 9 ms 12116 KB Output is correct
29 Correct 8 ms 12108 KB Output is correct
30 Correct 8 ms 11996 KB Output is correct
31 Correct 9 ms 12108 KB Output is correct
32 Correct 8 ms 11980 KB Output is correct
33 Correct 8 ms 12052 KB Output is correct
34 Correct 8 ms 11980 KB Output is correct
35 Correct 8 ms 11980 KB Output is correct
36 Correct 8 ms 12048 KB Output is correct
37 Correct 8 ms 11980 KB Output is correct
38 Correct 8 ms 12108 KB Output is correct
39 Correct 7 ms 11980 KB Output is correct
40 Correct 8 ms 12020 KB Output is correct
41 Correct 8 ms 11980 KB Output is correct
42 Correct 8 ms 12056 KB Output is correct
43 Correct 8 ms 12108 KB Output is correct
44 Correct 8 ms 11980 KB Output is correct
45 Correct 8 ms 11984 KB Output is correct
46 Correct 10 ms 11984 KB Output is correct
47 Correct 8 ms 11964 KB Output is correct
48 Correct 8 ms 12076 KB Output is correct
49 Correct 9 ms 12112 KB Output is correct
50 Correct 8 ms 12020 KB Output is correct
51 Correct 8 ms 11980 KB Output is correct
52 Correct 8 ms 11980 KB Output is correct
53 Correct 8 ms 12108 KB Output is correct
54 Correct 8 ms 11980 KB Output is correct
55 Correct 8 ms 11984 KB Output is correct
56 Correct 8 ms 12028 KB Output is correct
57 Correct 8 ms 12028 KB Output is correct
58 Correct 9 ms 12112 KB Output is correct

Subtask #3
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 11980 KB Output is correct
2 Correct 8 ms 11980 KB Output is correct
3 Correct 8 ms 11980 KB Output is correct
4 Correct 8 ms 12056 KB Output is correct
5 Correct 8 ms 11980 KB Output is correct
6 Correct 8 ms 11980 KB Output is correct
7 Correct 8 ms 11980 KB Output is correct
8 Correct 8 ms 11968 KB Output is correct
9 Correct 8 ms 11980 KB Output is correct
10 Correct 8 ms 11980 KB Output is correct
11 Correct 8 ms 11980 KB Output is correct
12 Correct 8 ms 11980 KB Output is correct
13 Correct 8 ms 11980 KB Output is correct
14 Correct 8 ms 12036 KB Output is correct
15 Correct 8 ms 11980 KB Output is correct
16 Correct 8 ms 11980 KB Output is correct
17 Correct 8 ms 11980 KB Output is correct
18 Correct 8 ms 11984 KB Output is correct
19 Correct 8 ms 11972 KB Output is correct
20 Correct 8 ms 12056 KB Output is correct
21 Correct 8 ms 11980 KB Output is correct
22 Correct 10 ms 12108 KB Output is correct
23 Correct 8 ms 12104 KB Output is correct
24 Correct 9 ms 12108 KB Output is correct
25 Correct 9 ms 12124 KB Output is correct
26 Correct 9 ms 12060 KB Output is correct
27 Correct 9 ms 12108 KB Output is correct
28 Correct 9 ms 12116 KB Output is correct
29 Correct 8 ms 12108 KB Output is correct
30 Correct 8 ms 11996 KB Output is correct
31 Correct 9 ms 12108 KB Output is correct
32 Correct 8 ms 11980 KB Output is correct
33 Correct 8 ms 12052 KB Output is correct
34 Correct 8 ms 11980 KB Output is correct
35 Correct 8 ms 11980 KB Output is correct
36 Correct 8 ms 12048 KB Output is correct
37 Correct 8 ms 11980 KB Output is correct
38 Correct 8 ms 12108 KB Output is correct
39 Correct 7 ms 11980 KB Output is correct
40 Correct 8 ms 12020 KB Output is correct
41 Correct 8 ms 11980 KB Output is correct
42 Correct 8 ms 12056 KB Output is correct
43 Correct 8 ms 12108 KB Output is correct
44 Correct 8 ms 11980 KB Output is correct
45 Correct 8 ms 11984 KB Output is correct
46 Correct 10 ms 11984 KB Output is correct
47 Correct 8 ms 11964 KB Output is correct
48 Correct 8 ms 12076 KB Output is correct
49 Correct 9 ms 12112 KB Output is correct
50 Correct 8 ms 12020 KB Output is correct
51 Correct 8 ms 11980 KB Output is correct
52 Correct 8 ms 11980 KB Output is correct
53 Correct 8 ms 12108 KB Output is correct
54 Correct 8 ms 11980 KB Output is correct
55 Correct 8 ms 11984 KB Output is correct
56 Correct 8 ms 12028 KB Output is correct
57 Correct 8 ms 12028 KB Output is correct
58 Correct 9 ms 12112 KB Output is correct
59 Correct 363 ms 30040 KB Output is correct
60 Correct 441 ms 32192 KB Output is correct
61 Correct 8 ms 11976 KB Output is correct
62 Correct 8 ms 11980 KB Output is correct
63 Correct 330 ms 28288 KB Output is correct
64 Correct 10 ms 12364 KB Output is correct
65 Correct 19 ms 13644 KB Output is correct
66 Correct 136 ms 24580 KB Output is correct
67 Correct 495 ms 58892 KB Output is correct
68 Correct 482 ms 49316 KB Output is correct
69 Correct 14 ms 12748 KB Output is correct
70 Correct 88 ms 19176 KB Output is correct
71 Correct 310 ms 35172 KB Output is correct
72 Correct 330 ms 34356 KB Output is correct
73 Correct 89 ms 17288 KB Output is correct
74 Correct 438 ms 31032 KB Output is correct
75 Correct 31 ms 14532 KB Output is correct
76 Correct 313 ms 34736 KB Output is correct
77 Correct 331 ms 35168 KB Output is correct
78 Correct 32 ms 14916 KB Output is correct
79 Correct 477 ms 42016 KB Output is correct
80 Correct 9 ms 12236 KB Output is correct
81 Correct 104 ms 19168 KB Output is correct
82 Correct 377 ms 33104 KB Output is correct
83 Correct 440 ms 31032 KB Output is correct
84 Correct 441 ms 31104 KB Output is correct
85 Correct 453 ms 31048 KB Output is correct
86 Correct 437 ms 32144 KB Output is correct
87 Correct 440 ms 32216 KB Output is correct