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Submission #96090

# Submission time Handle Problem Language Result Execution time Memory
96090 2019-02-05T17:47:34 Z andrei110901 Network (BOI15_net) C++14
63 / 100
 2000 ms 43556 KB 
#include <bits/stdc++.h>

using namespace std;

vector <vector <int>> ad;
vector <int> sub;
int nrf, cf;

void dfs(int nod, int par){
    if(ad[nod].size() == 1)
        sub[nod] = 1;
    for(auto fiu : ad[nod])
        if(fiu != par){
            dfs(fiu, nod);
            sub[nod] += sub[fiu];
        }
}

int get_centroid(int nod, int par){
    for(auto fiu : ad[nod])
        if(fiu != par && sub[fiu] > nrf / 2)
            return get_centroid(fiu, nod);
    return nod;
}

bool cmp(const vector <int> &a, const vector <int> &b){
    return a.size() > b.size();
}

void Frunza(int nod, int par, vector <int> &v){
    if(ad[nod].size() == 1){
        v.push_back(nod);
        return;
    }
    for(auto fiu : ad[nod])
        if(fiu != par)
            Frunza(fiu, nod, v);
}

int main()
{
    int n, x, y;
    cin >> n;
    nrf = n;
    ad.resize(n + 1);
    sub.resize(n + 1);
    for(int i = 1; i < n; i++){
        cin >> x >> y;
        ad[x].push_back(y);
        ad[y].push_back(x);
    }
    dfs(1, 0);
    nrf = sub[1];
    cf = get_centroid(1, 0);
    vector <vector <int>> gramezi;
    for(auto fiu : ad[cf]){
        vector <int> v;
        gramezi.push_back(v);
        Frunza(fiu, cf, gramezi.back());
    }
    sort(gramezi.begin(), gramezi.end(), cmp);
    cout << (nrf + 1) / 2 << '\n';
    if(nrf % 2 == 1){
        cout << cf << ' ' << gramezi[0].back() << '\n';
        gramezi[0].pop_back();
        sort(gramezi.begin(), gramezi.end(), cmp);
    }
    while(gramezi[0].size() > 0){
        cout << gramezi[0].back() << ' ' << gramezi[1].back() << '\n';
        gramezi[0].pop_back();
        gramezi[1].pop_back();
        sort(gramezi.begin(), gramezi.end(), cmp);
    }
    return 0;
}

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 256 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Correct 3 ms 376 KB Output is correct
4 Correct 2 ms 376 KB Output is correct
5 Correct 2 ms 256 KB Output is correct
6 Correct 2 ms 256 KB Output is correct
7 Correct 2 ms 376 KB Output is correct
8 Correct 2 ms 376 KB Output is correct
9 Correct 2 ms 256 KB Output is correct
10 Correct 2 ms 256 KB Output is correct
11 Correct 2 ms 256 KB Output is correct
12 Correct 2 ms 376 KB Output is correct
13 Correct 2 ms 376 KB Output is correct
14 Correct 2 ms 256 KB Output is correct
15 Correct 2 ms 256 KB Output is correct
16 Correct 2 ms 256 KB Output is correct
17 Correct 2 ms 376 KB Output is correct
18 Correct 2 ms 376 KB Output is correct
19 Correct 2 ms 256 KB Output is correct
20 Correct 2 ms 376 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 256 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Correct 3 ms 376 KB Output is correct
4 Correct 2 ms 376 KB Output is correct
5 Correct 2 ms 256 KB Output is correct
6 Correct 2 ms 256 KB Output is correct
7 Correct 2 ms 376 KB Output is correct
8 Correct 2 ms 376 KB Output is correct
9 Correct 2 ms 256 KB Output is correct
10 Correct 2 ms 256 KB Output is correct
11 Correct 2 ms 256 KB Output is correct
12 Correct 2 ms 376 KB Output is correct
13 Correct 2 ms 376 KB Output is correct
14 Correct 2 ms 256 KB Output is correct
15 Correct 2 ms 256 KB Output is correct
16 Correct 2 ms 256 KB Output is correct
17 Correct 2 ms 376 KB Output is correct
18 Correct 2 ms 376 KB Output is correct
19 Correct 2 ms 256 KB Output is correct
20 Correct 2 ms 376 KB Output is correct
21 Correct 2 ms 252 KB Output is correct
22 Correct 32 ms 544 KB Output is correct
23 Correct 31 ms 732 KB Output is correct
24 Correct 77 ms 504 KB Output is correct
25 Correct 16 ms 504 KB Output is correct
26 Correct 9 ms 376 KB Output is correct
27 Correct 3 ms 504 KB Output is correct
28 Correct 3 ms 376 KB Output is correct
29 Correct 3 ms 376 KB Output is correct
30 Correct 2 ms 256 KB Output is correct
31 Correct 3 ms 504 KB Output is correct
32 Correct 2 ms 376 KB Output is correct
33 Correct 2 ms 256 KB Output is correct
34 Correct 2 ms 380 KB Output is correct
35 Correct 2 ms 376 KB Output is correct
36 Correct 2 ms 376 KB Output is correct
37 Correct 2 ms 376 KB Output is correct
38 Correct 2 ms 376 KB Output is correct
39 Correct 2 ms 256 KB Output is correct
40 Correct 2 ms 256 KB Output is correct
41 Correct 2 ms 256 KB Output is correct
42 Correct 6 ms 376 KB Output is correct
43 Correct 20 ms 504 KB Output is correct
44 Correct 2 ms 256 KB Output is correct
45 Correct 3 ms 380 KB Output is correct
46 Correct 2 ms 376 KB Output is correct
47 Correct 2 ms 256 KB Output is correct
48 Correct 3 ms 376 KB Output is correct
49 Correct 9 ms 376 KB Output is correct
50 Correct 2 ms 376 KB Output is correct
51 Correct 2 ms 256 KB Output is correct
52 Correct 2 ms 376 KB Output is correct
53 Correct 2 ms 376 KB Output is correct
54 Correct 2 ms 380 KB Output is correct
55 Correct 3 ms 376 KB Output is correct
56 Correct 2 ms 376 KB Output is correct
57 Correct 4 ms 376 KB Output is correct
58 Correct 3 ms 504 KB Output is correct

Subtask #3
0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 256 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Correct 3 ms 376 KB Output is correct
4 Correct 2 ms 376 KB Output is correct
5 Correct 2 ms 256 KB Output is correct
6 Correct 2 ms 256 KB Output is correct
7 Correct 2 ms 376 KB Output is correct
8 Correct 2 ms 376 KB Output is correct
9 Correct 2 ms 256 KB Output is correct
10 Correct 2 ms 256 KB Output is correct
11 Correct 2 ms 256 KB Output is correct
12 Correct 2 ms 376 KB Output is correct
13 Correct 2 ms 376 KB Output is correct
14 Correct 2 ms 256 KB Output is correct
15 Correct 2 ms 256 KB Output is correct
16 Correct 2 ms 256 KB Output is correct
17 Correct 2 ms 376 KB Output is correct
18 Correct 2 ms 376 KB Output is correct
19 Correct 2 ms 256 KB Output is correct
20 Correct 2 ms 376 KB Output is correct
21 Correct 2 ms 252 KB Output is correct
22 Correct 32 ms 544 KB Output is correct
23 Correct 31 ms 732 KB Output is correct
24 Correct 77 ms 504 KB Output is correct
25 Correct 16 ms 504 KB Output is correct
26 Correct 9 ms 376 KB Output is correct
27 Correct 3 ms 504 KB Output is correct
28 Correct 3 ms 376 KB Output is correct
29 Correct 3 ms 376 KB Output is correct
30 Correct 2 ms 256 KB Output is correct
31 Correct 3 ms 504 KB Output is correct
32 Correct 2 ms 376 KB Output is correct
33 Correct 2 ms 256 KB Output is correct
34 Correct 2 ms 380 KB Output is correct
35 Correct 2 ms 376 KB Output is correct
36 Correct 2 ms 376 KB Output is correct
37 Correct 2 ms 376 KB Output is correct
38 Correct 2 ms 376 KB Output is correct
39 Correct 2 ms 256 KB Output is correct
40 Correct 2 ms 256 KB Output is correct
41 Correct 2 ms 256 KB Output is correct
42 Correct 6 ms 376 KB Output is correct
43 Correct 20 ms 504 KB Output is correct
44 Correct 2 ms 256 KB Output is correct
45 Correct 3 ms 380 KB Output is correct
46 Correct 2 ms 376 KB Output is correct
47 Correct 2 ms 256 KB Output is correct
48 Correct 3 ms 376 KB Output is correct
49 Correct 9 ms 376 KB Output is correct
50 Correct 2 ms 376 KB Output is correct
51 Correct 2 ms 256 KB Output is correct
52 Correct 2 ms 376 KB Output is correct
53 Correct 2 ms 376 KB Output is correct
54 Correct 2 ms 380 KB Output is correct
55 Correct 3 ms 376 KB Output is correct
56 Correct 2 ms 376 KB Output is correct
57 Correct 4 ms 376 KB Output is correct
58 Correct 3 ms 504 KB Output is correct
59 Execution timed out 2052 ms 43556 KB Time limit exceeded
60 Halted 0 ms 0 KB -