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Submission #477377

# Submission time Handle Problem Language Result Execution time Memory
477377 2021-10-01T19:54:56 Z Lobo Network (BOI15_net) C++17
100 / 100
 495 ms 115372 KB 
#include <bits/stdc++.h>
 
using namespace std;

const long long INFll = (long long) 1e18 + 10;
const int INFii = (int) 1e9 + 10;
typedef long long ll;
typedef int ii;
typedef long double dbl;
#define endl '\n'
#define sc second
#define fr first
#define mp make_pair
#define pb push_back
#define all(x) x.begin(), x.end()

#define maxn 3300000

ii n, gr[maxn];
vector<ii> ans, g[maxn];

void dfs(ii u, ii ant) {
    if(gr[u] == 1) {
        ans.pb(u);
    }

    for(auto v : g[u]) {
        if(v == ant) continue;

        dfs(v,u);
    }
}

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

    //freopen("in.in", "r", stdin);

    cin >> n;

    for(ii i = 0; i < n-1; i++) {
        ii u, v; cin >> u >> v;

        gr[u]++;
        gr[v]++;
        g[u].pb(v);
        g[v].pb(u);
    }

    dfs(1,1);
    
    cout << (ans.size()+1)/2 << endl;

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

    if(ans.size()%2 == 1) {
        cout << ans[ans.size()/2] << " ";
        if(ans[ans.size()/2] != 1) cout << 1 << endl;
        else cout << 2 << endl;
    }

}

Compilation message

net.cpp: In function 'int main()':
net.cpp:54:21: warning: comparison of integer expressions of different signedness: 'ii' {aka 'int'} and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   54 |     for(ii i = 0; i < ans.size()/2; i++) {
      |                   ~~^~~~~~~~~~~~~~

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 37 ms 77748 KB Output is correct
2 Correct 37 ms 77716 KB Output is correct
3 Correct 38 ms 77700 KB Output is correct
4 Correct 40 ms 77796 KB Output is correct
5 Correct 42 ms 77764 KB Output is correct
6 Correct 37 ms 77772 KB Output is correct
7 Correct 38 ms 77816 KB Output is correct
8 Correct 39 ms 77776 KB Output is correct
9 Correct 42 ms 77696 KB Output is correct
10 Correct 42 ms 77764 KB Output is correct
11 Correct 39 ms 77772 KB Output is correct
12 Correct 40 ms 77752 KB Output is correct
13 Correct 39 ms 77772 KB Output is correct
14 Correct 41 ms 77692 KB Output is correct
15 Correct 37 ms 77800 KB Output is correct
16 Correct 37 ms 77772 KB Output is correct
17 Correct 38 ms 77772 KB Output is correct
18 Correct 40 ms 77796 KB Output is correct
19 Correct 41 ms 77780 KB Output is correct
20 Correct 48 ms 77748 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 37 ms 77748 KB Output is correct
2 Correct 37 ms 77716 KB Output is correct
3 Correct 38 ms 77700 KB Output is correct
4 Correct 40 ms 77796 KB Output is correct
5 Correct 42 ms 77764 KB Output is correct
6 Correct 37 ms 77772 KB Output is correct
7 Correct 38 ms 77816 KB Output is correct
8 Correct 39 ms 77776 KB Output is correct
9 Correct 42 ms 77696 KB Output is correct
10 Correct 42 ms 77764 KB Output is correct
11 Correct 39 ms 77772 KB Output is correct
12 Correct 40 ms 77752 KB Output is correct
13 Correct 39 ms 77772 KB Output is correct
14 Correct 41 ms 77692 KB Output is correct
15 Correct 37 ms 77800 KB Output is correct
16 Correct 37 ms 77772 KB Output is correct
17 Correct 38 ms 77772 KB Output is correct
18 Correct 40 ms 77796 KB Output is correct
19 Correct 41 ms 77780 KB Output is correct
20 Correct 48 ms 77748 KB Output is correct
21 Correct 39 ms 77776 KB Output is correct
22 Correct 40 ms 77928 KB Output is correct
23 Correct 43 ms 77928 KB Output is correct
24 Correct 39 ms 77800 KB Output is correct
25 Correct 39 ms 77900 KB Output is correct
26 Correct 40 ms 77872 KB Output is correct
27 Correct 39 ms 77900 KB Output is correct
28 Correct 39 ms 77908 KB Output is correct
29 Correct 37 ms 77796 KB Output is correct
30 Correct 39 ms 77828 KB Output is correct
31 Correct 44 ms 77856 KB Output is correct
32 Correct 42 ms 77852 KB Output is correct
33 Correct 40 ms 77704 KB Output is correct
34 Correct 41 ms 77792 KB Output is correct
35 Correct 42 ms 77704 KB Output is correct
36 Correct 41 ms 77728 KB Output is correct
37 Correct 42 ms 77852 KB Output is correct
38 Correct 40 ms 77796 KB Output is correct
39 Correct 43 ms 77796 KB Output is correct
40 Correct 37 ms 77732 KB Output is correct
41 Correct 38 ms 77740 KB Output is correct
42 Correct 38 ms 77768 KB Output is correct
43 Correct 38 ms 77860 KB Output is correct
44 Correct 40 ms 77736 KB Output is correct
45 Correct 39 ms 77756 KB Output is correct
46 Correct 43 ms 77900 KB Output is correct
47 Correct 44 ms 77828 KB Output is correct
48 Correct 39 ms 77788 KB Output is correct
49 Correct 46 ms 77768 KB Output is correct
50 Correct 39 ms 77776 KB Output is correct
51 Correct 38 ms 77756 KB Output is correct
52 Correct 43 ms 77716 KB Output is correct
53 Correct 39 ms 77944 KB Output is correct
54 Correct 40 ms 77776 KB Output is correct
55 Correct 42 ms 77808 KB Output is correct
56 Correct 39 ms 77776 KB Output is correct
57 Correct 39 ms 77756 KB Output is correct
58 Correct 43 ms 77868 KB Output is correct

Subtask #3
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 37 ms 77748 KB Output is correct
2 Correct 37 ms 77716 KB Output is correct
3 Correct 38 ms 77700 KB Output is correct
4 Correct 40 ms 77796 KB Output is correct
5 Correct 42 ms 77764 KB Output is correct
6 Correct 37 ms 77772 KB Output is correct
7 Correct 38 ms 77816 KB Output is correct
8 Correct 39 ms 77776 KB Output is correct
9 Correct 42 ms 77696 KB Output is correct
10 Correct 42 ms 77764 KB Output is correct
11 Correct 39 ms 77772 KB Output is correct
12 Correct 40 ms 77752 KB Output is correct
13 Correct 39 ms 77772 KB Output is correct
14 Correct 41 ms 77692 KB Output is correct
15 Correct 37 ms 77800 KB Output is correct
16 Correct 37 ms 77772 KB Output is correct
17 Correct 38 ms 77772 KB Output is correct
18 Correct 40 ms 77796 KB Output is correct
19 Correct 41 ms 77780 KB Output is correct
20 Correct 48 ms 77748 KB Output is correct
21 Correct 39 ms 77776 KB Output is correct
22 Correct 40 ms 77928 KB Output is correct
23 Correct 43 ms 77928 KB Output is correct
24 Correct 39 ms 77800 KB Output is correct
25 Correct 39 ms 77900 KB Output is correct
26 Correct 40 ms 77872 KB Output is correct
27 Correct 39 ms 77900 KB Output is correct
28 Correct 39 ms 77908 KB Output is correct
29 Correct 37 ms 77796 KB Output is correct
30 Correct 39 ms 77828 KB Output is correct
31 Correct 44 ms 77856 KB Output is correct
32 Correct 42 ms 77852 KB Output is correct
33 Correct 40 ms 77704 KB Output is correct
34 Correct 41 ms 77792 KB Output is correct
35 Correct 42 ms 77704 KB Output is correct
36 Correct 41 ms 77728 KB Output is correct
37 Correct 42 ms 77852 KB Output is correct
38 Correct 40 ms 77796 KB Output is correct
39 Correct 43 ms 77796 KB Output is correct
40 Correct 37 ms 77732 KB Output is correct
41 Correct 38 ms 77740 KB Output is correct
42 Correct 38 ms 77768 KB Output is correct
43 Correct 38 ms 77860 KB Output is correct
44 Correct 40 ms 77736 KB Output is correct
45 Correct 39 ms 77756 KB Output is correct
46 Correct 43 ms 77900 KB Output is correct
47 Correct 44 ms 77828 KB Output is correct
48 Correct 39 ms 77788 KB Output is correct
49 Correct 46 ms 77768 KB Output is correct
50 Correct 39 ms 77776 KB Output is correct
51 Correct 38 ms 77756 KB Output is correct
52 Correct 43 ms 77716 KB Output is correct
53 Correct 39 ms 77944 KB Output is correct
54 Correct 40 ms 77776 KB Output is correct
55 Correct 42 ms 77808 KB Output is correct
56 Correct 39 ms 77776 KB Output is correct
57 Correct 39 ms 77756 KB Output is correct
58 Correct 43 ms 77868 KB Output is correct
59 Correct 374 ms 103516 KB Output is correct
60 Correct 433 ms 106424 KB Output is correct
61 Correct 40 ms 77776 KB Output is correct
62 Correct 40 ms 77824 KB Output is correct
63 Correct 319 ms 100864 KB Output is correct
64 Correct 42 ms 78168 KB Output is correct
65 Correct 53 ms 79760 KB Output is correct
66 Correct 145 ms 94372 KB Output is correct
67 Correct 477 ms 114600 KB Output is correct
68 Correct 489 ms 115372 KB Output is correct
69 Correct 44 ms 78664 KB Output is correct
70 Correct 107 ms 87604 KB Output is correct
71 Correct 313 ms 109660 KB Output is correct
72 Correct 329 ms 108324 KB Output is correct
73 Correct 111 ms 85396 KB Output is correct
74 Correct 428 ms 105388 KB Output is correct
75 Correct 66 ms 81200 KB Output is correct
76 Correct 320 ms 109300 KB Output is correct
77 Correct 299 ms 109272 KB Output is correct
78 Correct 61 ms 81236 KB Output is correct
79 Correct 495 ms 112896 KB Output is correct
80 Correct 42 ms 78020 KB Output is correct
81 Correct 138 ms 87624 KB Output is correct
82 Correct 374 ms 107232 KB Output is correct
83 Correct 421 ms 105408 KB Output is correct
84 Correct 450 ms 105360 KB Output is correct
85 Correct 411 ms 105540 KB Output is correct
86 Correct 434 ms 106428 KB Output is correct
87 Correct 418 ms 106400 KB Output is correct