oj.uz

Submission #672873

# Submission time Handle Problem Language Result Execution time Memory
672873 2022-12-18T18:04:34 Z iosif_andrei_ Network (BOI15_net) C++14
0 / 100
 7 ms 12052 KB 
#include <bits/stdc++.h> 
using namespace std;

int n, h[500001];
vector <int> g[500001];

void dfs(int nod, int lvl)
{
    h[nod] = lvl;

    for (auto& i : g[nod])
        if (!h[i])
            dfs(i, lvl + 1);
}

struct nod {
    int key;

    bool operator < (nod aux)
    {
        return h[key] < h[aux.key];
    }
};

vector <nod> v;

int main() {
    
    cin >> n;

    for (int i = 1; i < n; i++)
    {
        int x, y;
        cin >> x >> y;
        g[x].push_back(y);
        g[y].push_back(x);
    }

    int root;

    for (int i = 1; i <= n; i++)
        if (g[i].size() == 1)
        {
            root = i;
            break;
        }

    dfs(root, 1);

    for (int i = 1; i <= n; i++)
        if (g[i].size() == 1)
            v.push_back({ i });

    cout << (v.size() + 1) / 2 << '\n';

    sort(v.begin(), v.end());

    int i = 0, j = v.size() - 1;

    while (i < j)
    {
        cout << v[i].key << ' ' << v[j].key << '\n';
        i++;
        j--;
    }

    if (i == j)
        if (g[v[i].key][0] == 1)
            cout << v[i].key << ' ' << 2;
        else
            cout << v[i].key << ' ' << 1;

    return 0;
}

Compilation message

net.cpp: In function 'int main()':
net.cpp:67:8: warning: suggest explicit braces to avoid ambiguous 'else' [-Wdangling-else]
   67 |     if (i == j)
      |        ^
net.cpp:48:8: warning: 'root' may be used uninitialized in this function [-Wmaybe-uninitialized]
   48 |     dfs(root, 1);
      |     ~~~^~~~~~~~~

Subtask #1
0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 11988 KB Output is correct
2 Correct 6 ms 11988 KB Output is correct
3 Correct 6 ms 11988 KB Output is correct
4 Correct 6 ms 11988 KB Output is correct
5 Correct 6 ms 11988 KB Output is correct
6 Correct 6 ms 11988 KB Output is correct
7 Correct 7 ms 11952 KB Output is correct
8 Correct 6 ms 11988 KB Output is correct
9 Correct 6 ms 11988 KB Output is correct
10 Correct 6 ms 12052 KB Output is correct
11 Correct 6 ms 11988 KB Output is correct
12 Correct 6 ms 11988 KB Output is correct
13 Correct 6 ms 11988 KB Output is correct
14 Correct 7 ms 11988 KB Output is correct
15 Correct 6 ms 11988 KB Output is correct
16 Correct 6 ms 11988 KB Output is correct
17 Correct 6 ms 11988 KB Output is correct
18 Incorrect 6 ms 11936 KB Breaking single line is causing network to disconnect.
19 Halted 0 ms 0 KB -

Subtask #2
0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 11988 KB Output is correct
2 Correct 6 ms 11988 KB Output is correct
3 Correct 6 ms 11988 KB Output is correct
4 Correct 6 ms 11988 KB Output is correct
5 Correct 6 ms 11988 KB Output is correct
6 Correct 6 ms 11988 KB Output is correct
7 Correct 7 ms 11952 KB Output is correct
8 Correct 6 ms 11988 KB Output is correct
9 Correct 6 ms 11988 KB Output is correct
10 Correct 6 ms 12052 KB Output is correct
11 Correct 6 ms 11988 KB Output is correct
12 Correct 6 ms 11988 KB Output is correct
13 Correct 6 ms 11988 KB Output is correct
14 Correct 7 ms 11988 KB Output is correct
15 Correct 6 ms 11988 KB Output is correct
16 Correct 6 ms 11988 KB Output is correct
17 Correct 6 ms 11988 KB Output is correct
18 Incorrect 6 ms 11936 KB Breaking single line is causing network to disconnect.
19 Halted 0 ms 0 KB -

Subtask #3
0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 11988 KB Output is correct
2 Correct 6 ms 11988 KB Output is correct
3 Correct 6 ms 11988 KB Output is correct
4 Correct 6 ms 11988 KB Output is correct
5 Correct 6 ms 11988 KB Output is correct
6 Correct 6 ms 11988 KB Output is correct
7 Correct 7 ms 11952 KB Output is correct
8 Correct 6 ms 11988 KB Output is correct
9 Correct 6 ms 11988 KB Output is correct
10 Correct 6 ms 12052 KB Output is correct
11 Correct 6 ms 11988 KB Output is correct
12 Correct 6 ms 11988 KB Output is correct
13 Correct 6 ms 11988 KB Output is correct
14 Correct 7 ms 11988 KB Output is correct
15 Correct 6 ms 11988 KB Output is correct
16 Correct 6 ms 11988 KB Output is correct
17 Correct 6 ms 11988 KB Output is correct
18 Incorrect 6 ms 11936 KB Breaking single line is causing network to disconnect.
19 Halted 0 ms 0 KB -