Submission #705324

# Submission time Handle Problem Language Result Execution time Memory
705324 2023-03-04T01:07:59 Z anha3k25cvp Network (BOI15_net) C++14
100 / 100
411 ms 49836 KB
#include <bits/stdc++.h>
#define ll long long
#define dl double
#define st first
#define nd second
#define II pair <int, int>

using namespace std;

const int N = 1 + 1e5;
const int inf = 7 + 1e9;

vector <int> h, q;
vector <vector <int>> g;

void dfs(int u) {
    if (g[u].size() == 1)
        q.push_back(u);
    for (int v : g[u])
        if (!h[v]) {
            h[v] = h[u] + 1;
            dfs(v);
        }
}

int main() {
#define TASKNAME "net"
    ios_base :: sync_with_stdio (0);
    cin.tie (0);
    if ( fopen( TASKNAME".inp", "r" ) ) {
        freopen( TASKNAME".inp", "r", stdin );
        freopen( TASKNAME".out", "w", stdout );
    }
    int n;
    cin >> n;
    g.resize(n + 1);
    for (int i = 1; i < n; i ++) {
        int u, v;
        cin >> u >> v;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    h.assign(n + 1, 0);
    h[1] = 1;
    dfs(1);
    int m = q.size();
    vector <II> ans;
    for (int i = 0; i < m / 2; i ++)
        ans.push_back({q[i], q[(m / 2) + i]});
    if (m & 1)
        ans.push_back({q[0], q.back()});
    cout << ans.size() << '\n';
    for (auto z : ans)
        cout << z.st << ' ' << z.nd << '\n';
    return 0;
}

Compilation message

net.cpp: In function 'int main()':
net.cpp:31:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   31 |         freopen( TASKNAME".inp", "r", stdin );
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
net.cpp:32:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   32 |         freopen( TASKNAME".out", "w", stdout );
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 0 ms 224 KB Output is correct
4 Correct 0 ms 316 KB Output is correct
5 Correct 1 ms 316 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 324 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 0 ms 324 KB Output is correct
10 Correct 0 ms 212 KB Output is correct
11 Correct 0 ms 212 KB Output is correct
12 Correct 0 ms 212 KB Output is correct
13 Correct 0 ms 212 KB Output is correct
14 Correct 0 ms 212 KB Output is correct
15 Correct 1 ms 212 KB Output is correct
16 Correct 0 ms 212 KB Output is correct
17 Correct 0 ms 212 KB Output is correct
18 Correct 0 ms 320 KB Output is correct
19 Correct 1 ms 212 KB Output is correct
20 Correct 1 ms 212 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 0 ms 224 KB Output is correct
4 Correct 0 ms 316 KB Output is correct
5 Correct 1 ms 316 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 324 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 0 ms 324 KB Output is correct
10 Correct 0 ms 212 KB Output is correct
11 Correct 0 ms 212 KB Output is correct
12 Correct 0 ms 212 KB Output is correct
13 Correct 0 ms 212 KB Output is correct
14 Correct 0 ms 212 KB Output is correct
15 Correct 1 ms 212 KB Output is correct
16 Correct 0 ms 212 KB Output is correct
17 Correct 0 ms 212 KB Output is correct
18 Correct 0 ms 320 KB Output is correct
19 Correct 1 ms 212 KB Output is correct
20 Correct 1 ms 212 KB Output is correct
21 Correct 0 ms 212 KB Output is correct
22 Correct 1 ms 468 KB Output is correct
23 Correct 1 ms 468 KB Output is correct
24 Correct 1 ms 468 KB Output is correct
25 Correct 1 ms 468 KB Output is correct
26 Correct 1 ms 340 KB Output is correct
27 Correct 1 ms 432 KB Output is correct
28 Correct 1 ms 468 KB Output is correct
29 Correct 1 ms 340 KB Output is correct
30 Correct 0 ms 212 KB Output is correct
31 Correct 1 ms 468 KB Output is correct
32 Correct 0 ms 212 KB Output is correct
33 Correct 1 ms 212 KB Output is correct
34 Correct 0 ms 320 KB Output is correct
35 Correct 0 ms 212 KB Output is correct
36 Correct 0 ms 212 KB Output is correct
37 Correct 1 ms 324 KB Output is correct
38 Correct 1 ms 340 KB Output is correct
39 Correct 0 ms 320 KB Output is correct
40 Correct 0 ms 316 KB Output is correct
41 Correct 0 ms 320 KB Output is correct
42 Correct 1 ms 340 KB Output is correct
43 Correct 1 ms 340 KB Output is correct
44 Correct 0 ms 212 KB Output is correct
45 Correct 1 ms 340 KB Output is correct
46 Correct 1 ms 340 KB Output is correct
47 Correct 0 ms 212 KB Output is correct
48 Correct 0 ms 340 KB Output is correct
49 Correct 1 ms 340 KB Output is correct
50 Correct 0 ms 212 KB Output is correct
51 Correct 1 ms 212 KB Output is correct
52 Correct 0 ms 324 KB Output is correct
53 Correct 1 ms 340 KB Output is correct
54 Correct 1 ms 324 KB Output is correct
55 Correct 1 ms 340 KB Output is correct
56 Correct 1 ms 212 KB Output is correct
57 Correct 1 ms 324 KB Output is correct
58 Correct 1 ms 468 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 0 ms 224 KB Output is correct
4 Correct 0 ms 316 KB Output is correct
5 Correct 1 ms 316 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 324 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 0 ms 324 KB Output is correct
10 Correct 0 ms 212 KB Output is correct
11 Correct 0 ms 212 KB Output is correct
12 Correct 0 ms 212 KB Output is correct
13 Correct 0 ms 212 KB Output is correct
14 Correct 0 ms 212 KB Output is correct
15 Correct 1 ms 212 KB Output is correct
16 Correct 0 ms 212 KB Output is correct
17 Correct 0 ms 212 KB Output is correct
18 Correct 0 ms 320 KB Output is correct
19 Correct 1 ms 212 KB Output is correct
20 Correct 1 ms 212 KB Output is correct
21 Correct 0 ms 212 KB Output is correct
22 Correct 1 ms 468 KB Output is correct
23 Correct 1 ms 468 KB Output is correct
24 Correct 1 ms 468 KB Output is correct
25 Correct 1 ms 468 KB Output is correct
26 Correct 1 ms 340 KB Output is correct
27 Correct 1 ms 432 KB Output is correct
28 Correct 1 ms 468 KB Output is correct
29 Correct 1 ms 340 KB Output is correct
30 Correct 0 ms 212 KB Output is correct
31 Correct 1 ms 468 KB Output is correct
32 Correct 0 ms 212 KB Output is correct
33 Correct 1 ms 212 KB Output is correct
34 Correct 0 ms 320 KB Output is correct
35 Correct 0 ms 212 KB Output is correct
36 Correct 0 ms 212 KB Output is correct
37 Correct 1 ms 324 KB Output is correct
38 Correct 1 ms 340 KB Output is correct
39 Correct 0 ms 320 KB Output is correct
40 Correct 0 ms 316 KB Output is correct
41 Correct 0 ms 320 KB Output is correct
42 Correct 1 ms 340 KB Output is correct
43 Correct 1 ms 340 KB Output is correct
44 Correct 0 ms 212 KB Output is correct
45 Correct 1 ms 340 KB Output is correct
46 Correct 1 ms 340 KB Output is correct
47 Correct 0 ms 212 KB Output is correct
48 Correct 0 ms 340 KB Output is correct
49 Correct 1 ms 340 KB Output is correct
50 Correct 0 ms 212 KB Output is correct
51 Correct 1 ms 212 KB Output is correct
52 Correct 0 ms 324 KB Output is correct
53 Correct 1 ms 340 KB Output is correct
54 Correct 1 ms 324 KB Output is correct
55 Correct 1 ms 340 KB Output is correct
56 Correct 1 ms 212 KB Output is correct
57 Correct 1 ms 324 KB Output is correct
58 Correct 1 ms 468 KB Output is correct
59 Correct 284 ms 37760 KB Output is correct
60 Correct 350 ms 42032 KB Output is correct
61 Correct 0 ms 324 KB Output is correct
62 Correct 1 ms 212 KB Output is correct
63 Correct 240 ms 34012 KB Output is correct
64 Correct 2 ms 852 KB Output is correct
65 Correct 9 ms 2800 KB Output is correct
66 Correct 101 ms 21048 KB Output is correct
67 Correct 411 ms 48928 KB Output is correct
68 Correct 396 ms 49836 KB Output is correct
69 Correct 6 ms 1620 KB Output is correct
70 Correct 68 ms 14440 KB Output is correct
71 Correct 233 ms 45712 KB Output is correct
72 Correct 252 ms 44348 KB Output is correct
73 Correct 63 ms 11344 KB Output is correct
74 Correct 348 ms 40660 KB Output is correct
75 Correct 19 ms 5200 KB Output is correct
76 Correct 240 ms 45420 KB Output is correct
77 Correct 244 ms 45484 KB Output is correct
78 Correct 25 ms 5196 KB Output is correct
79 Correct 387 ms 47124 KB Output is correct
80 Correct 2 ms 596 KB Output is correct
81 Correct 75 ms 14648 KB Output is correct
82 Correct 299 ms 42988 KB Output is correct
83 Correct 354 ms 40608 KB Output is correct
84 Correct 346 ms 40644 KB Output is correct
85 Correct 342 ms 40652 KB Output is correct
86 Correct 354 ms 42036 KB Output is correct
87 Correct 350 ms 42048 KB Output is correct