oj.uz

Submission #519928

# Submission time Handle Problem Language Result Execution time Memory
519928 2022-01-27T19:17:52 Z Hacv16 Network (BOI15_net) C++17
100 / 100
 481 ms 82996 KB 
#include<bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<int, int> pii;

const int MAX = 2e6 + 15;
const int INF = 0x3f3f3f3f;
const int MOD = 1e9 + 7;

#define pb push_back
#define sz(x) (int) x.size()
#define fr first
#define sc second
#define mp make_pair
#define all(x) x.begin(), x.end()
#define dbg(x) cout << #x << ": " << "[ " << x << " ]\n"

int n;
vector<int> adj[MAX], l;

void setIO(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL); 
}

void dfs(int x, int p){
    if(sz(adj[x]) == 1){
        l.pb(x);
    }

    for(auto v : adj[x]){
        if(v == p) continue;
        dfs(v, x);
    }
}

int main(){
    setIO();

    cin >> n;

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

        adj[u].pb(v);
        adj[v].pb(u);
    }

    dfs(1, -1);

    int e = sz(l) / 2 + (sz(l) % 2);

    cout << e << '\n';

    for(int i = 0; i < e; i++){
        int u = l[i], v = (i + sz(l)/2 < sz(l) ? l[i + sz(l)/2] : l[0]);
        cout << u << ' ' << v << '\n';
    }

    return 0;
}

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 26 ms 47184 KB Output is correct
2 Correct 23 ms 47260 KB Output is correct
3 Correct 24 ms 47184 KB Output is correct
4 Correct 23 ms 47188 KB Output is correct
5 Correct 25 ms 47184 KB Output is correct
6 Correct 24 ms 47184 KB Output is correct
7 Correct 24 ms 47272 KB Output is correct
8 Correct 28 ms 47188 KB Output is correct
9 Correct 23 ms 47216 KB Output is correct
10 Correct 24 ms 47280 KB Output is correct
11 Correct 24 ms 47276 KB Output is correct
12 Correct 23 ms 47208 KB Output is correct
13 Correct 24 ms 47184 KB Output is correct
14 Correct 23 ms 47264 KB Output is correct
15 Correct 24 ms 47264 KB Output is correct
16 Correct 23 ms 47184 KB Output is correct
17 Correct 25 ms 47264 KB Output is correct
18 Correct 24 ms 47268 KB Output is correct
19 Correct 23 ms 47184 KB Output is correct
20 Correct 23 ms 47184 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 26 ms 47184 KB Output is correct
2 Correct 23 ms 47260 KB Output is correct
3 Correct 24 ms 47184 KB Output is correct
4 Correct 23 ms 47188 KB Output is correct
5 Correct 25 ms 47184 KB Output is correct
6 Correct 24 ms 47184 KB Output is correct
7 Correct 24 ms 47272 KB Output is correct
8 Correct 28 ms 47188 KB Output is correct
9 Correct 23 ms 47216 KB Output is correct
10 Correct 24 ms 47280 KB Output is correct
11 Correct 24 ms 47276 KB Output is correct
12 Correct 23 ms 47208 KB Output is correct
13 Correct 24 ms 47184 KB Output is correct
14 Correct 23 ms 47264 KB Output is correct
15 Correct 24 ms 47264 KB Output is correct
16 Correct 23 ms 47184 KB Output is correct
17 Correct 25 ms 47264 KB Output is correct
18 Correct 24 ms 47268 KB Output is correct
19 Correct 23 ms 47184 KB Output is correct
20 Correct 23 ms 47184 KB Output is correct
21 Correct 23 ms 47260 KB Output is correct
22 Correct 24 ms 47400 KB Output is correct
23 Correct 25 ms 47296 KB Output is correct
24 Correct 29 ms 47396 KB Output is correct
25 Correct 26 ms 47280 KB Output is correct
26 Correct 26 ms 47272 KB Output is correct
27 Correct 25 ms 47372 KB Output is correct
28 Correct 27 ms 47304 KB Output is correct
29 Correct 24 ms 47312 KB Output is correct
30 Correct 24 ms 47180 KB Output is correct
31 Correct 30 ms 47392 KB Output is correct
32 Correct 26 ms 47212 KB Output is correct
33 Correct 25 ms 47280 KB Output is correct
34 Correct 25 ms 47284 KB Output is correct
35 Correct 28 ms 47196 KB Output is correct
36 Correct 30 ms 47284 KB Output is correct
37 Correct 26 ms 47324 KB Output is correct
38 Correct 29 ms 47284 KB Output is correct
39 Correct 24 ms 47208 KB Output is correct
40 Correct 23 ms 47176 KB Output is correct
41 Correct 22 ms 47184 KB Output is correct
42 Correct 26 ms 47220 KB Output is correct
43 Correct 24 ms 47292 KB Output is correct
44 Correct 24 ms 47184 KB Output is correct
45 Correct 23 ms 47224 KB Output is correct
46 Correct 24 ms 47312 KB Output is correct
47 Correct 22 ms 47184 KB Output is correct
48 Correct 23 ms 47184 KB Output is correct
49 Correct 24 ms 47276 KB Output is correct
50 Correct 23 ms 47244 KB Output is correct
51 Correct 25 ms 47264 KB Output is correct
52 Correct 24 ms 47260 KB Output is correct
53 Correct 24 ms 47248 KB Output is correct
54 Correct 25 ms 47312 KB Output is correct
55 Correct 24 ms 47296 KB Output is correct
56 Correct 23 ms 47184 KB Output is correct
57 Correct 26 ms 47312 KB Output is correct
58 Correct 24 ms 47280 KB Output is correct

Subtask #3
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 26 ms 47184 KB Output is correct
2 Correct 23 ms 47260 KB Output is correct
3 Correct 24 ms 47184 KB Output is correct
4 Correct 23 ms 47188 KB Output is correct
5 Correct 25 ms 47184 KB Output is correct
6 Correct 24 ms 47184 KB Output is correct
7 Correct 24 ms 47272 KB Output is correct
8 Correct 28 ms 47188 KB Output is correct
9 Correct 23 ms 47216 KB Output is correct
10 Correct 24 ms 47280 KB Output is correct
11 Correct 24 ms 47276 KB Output is correct
12 Correct 23 ms 47208 KB Output is correct
13 Correct 24 ms 47184 KB Output is correct
14 Correct 23 ms 47264 KB Output is correct
15 Correct 24 ms 47264 KB Output is correct
16 Correct 23 ms 47184 KB Output is correct
17 Correct 25 ms 47264 KB Output is correct
18 Correct 24 ms 47268 KB Output is correct
19 Correct 23 ms 47184 KB Output is correct
20 Correct 23 ms 47184 KB Output is correct
21 Correct 23 ms 47260 KB Output is correct
22 Correct 24 ms 47400 KB Output is correct
23 Correct 25 ms 47296 KB Output is correct
24 Correct 29 ms 47396 KB Output is correct
25 Correct 26 ms 47280 KB Output is correct
26 Correct 26 ms 47272 KB Output is correct
27 Correct 25 ms 47372 KB Output is correct
28 Correct 27 ms 47304 KB Output is correct
29 Correct 24 ms 47312 KB Output is correct
30 Correct 24 ms 47180 KB Output is correct
31 Correct 30 ms 47392 KB Output is correct
32 Correct 26 ms 47212 KB Output is correct
33 Correct 25 ms 47280 KB Output is correct
34 Correct 25 ms 47284 KB Output is correct
35 Correct 28 ms 47196 KB Output is correct
36 Correct 30 ms 47284 KB Output is correct
37 Correct 26 ms 47324 KB Output is correct
38 Correct 29 ms 47284 KB Output is correct
39 Correct 24 ms 47208 KB Output is correct
40 Correct 23 ms 47176 KB Output is correct
41 Correct 22 ms 47184 KB Output is correct
42 Correct 26 ms 47220 KB Output is correct
43 Correct 24 ms 47292 KB Output is correct
44 Correct 24 ms 47184 KB Output is correct
45 Correct 23 ms 47224 KB Output is correct
46 Correct 24 ms 47312 KB Output is correct
47 Correct 22 ms 47184 KB Output is correct
48 Correct 23 ms 47184 KB Output is correct
49 Correct 24 ms 47276 KB Output is correct
50 Correct 23 ms 47244 KB Output is correct
51 Correct 25 ms 47264 KB Output is correct
52 Correct 24 ms 47260 KB Output is correct
53 Correct 24 ms 47248 KB Output is correct
54 Correct 25 ms 47312 KB Output is correct
55 Correct 24 ms 47296 KB Output is correct
56 Correct 23 ms 47184 KB Output is correct
57 Correct 26 ms 47312 KB Output is correct
58 Correct 24 ms 47280 KB Output is correct
59 Correct 310 ms 71436 KB Output is correct
60 Correct 378 ms 74104 KB Output is correct
61 Correct 24 ms 47176 KB Output is correct
62 Correct 24 ms 47184 KB Output is correct
63 Correct 266 ms 68776 KB Output is correct
64 Correct 27 ms 47684 KB Output is correct
65 Correct 31 ms 49140 KB Output is correct
66 Correct 150 ms 63048 KB Output is correct
67 Correct 481 ms 82104 KB Output is correct
68 Correct 463 ms 82996 KB Output is correct
69 Correct 30 ms 48144 KB Output is correct
70 Correct 112 ms 56484 KB Output is correct
71 Correct 344 ms 77036 KB Output is correct
72 Correct 306 ms 75900 KB Output is correct
73 Correct 107 ms 54280 KB Output is correct
74 Correct 400 ms 72856 KB Output is correct
75 Correct 46 ms 50376 KB Output is correct
76 Correct 279 ms 76756 KB Output is correct
77 Correct 291 ms 76852 KB Output is correct
78 Correct 44 ms 50484 KB Output is correct
79 Correct 454 ms 80492 KB Output is correct
80 Correct 27 ms 47476 KB Output is correct
81 Correct 96 ms 56512 KB Output is correct
82 Correct 349 ms 74872 KB Output is correct
83 Correct 457 ms 72912 KB Output is correct
84 Correct 393 ms 72848 KB Output is correct
85 Correct 378 ms 72896 KB Output is correct
86 Correct 364 ms 73912 KB Output is correct
87 Correct 432 ms 73936 KB Output is correct