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Submission #633951

# Submission time Handle Problem Language Result Execution time Memory
633951 2022-08-23T13:49:48 Z MinaRagy06 Network (BOI15_net) C++17
0 / 100
 6 ms 11988 KB 
#include <bits/stdc++.h>
using namespace std;
#define lesgooo ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0)
#define endl    '\n'
#define int     long long

const int N = 5e5+5;
vector<int> adj[N], leaf;
void dfs(int i, int par)
{
    if (adj[i].size() == 1) return leaf.push_back(i), void();
    for (auto nxt : adj[i]) if (nxt != par) dfs(nxt, i);
}
int mx = 0, val = 0;
void dfs2(int i, int par, int sum)
{
    if (sum > mx) mx = sum ,val = i;
    for (auto nxt : adj[i]) if (nxt != par) dfs2(nxt, i, sum+1);
}
signed main()
{
    lesgooo;
    int n, u, v;
    cin >> n;
    for (int i =1 ; i < n; i++) cin >> u >> v, adj[--u].push_back(--v), adj[v].push_back(u);
    int mxx = 0, vall = 0;
    for (int i = 0; i < n; i++) if (adj[i].size() > mxx) mxx = adj[i].size(), vall = i;
    dfs(vall, -1);
    cout << (leaf.size()+1)/2 << endl;
    for (int i = 0; i < leaf.size()/2; i++) cout << leaf[i]+1 << " " << leaf[leaf.size()/2+i]+1 << endl;
    dfs2(leaf.back(), -1, 0), cout << leaf.back()+1 << " " << val+1 << endl;
    return 0;
}

Compilation message

net.cpp: In function 'int main()':
net.cpp:27:51: warning: comparison of integer expressions of different signedness: 'std::vector<long long int>::size_type' {aka 'long unsigned int'} and 'long long int' [-Wsign-compare]
   27 |     for (int i = 0; i < n; i++) if (adj[i].size() > mxx) mxx = adj[i].size(), vall = i;
      |                                     ~~~~~~~~~~~~~~^~~~~
net.cpp:30:23: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   30 |     for (int i = 0; i < leaf.size()/2; i++) cout << leaf[i]+1 << " " << leaf[leaf.size()/2+i]+1 << endl;
      |                     ~~^~~~~~~~~~~~~~~

Subtask #1
0 / 18.0

# Verdict Execution time Memory Grader output
1 Incorrect 6 ms 11988 KB Extra information in the output file
2 Halted 0 ms 0 KB -

Subtask #2
0 / 45.0

# Verdict Execution time Memory Grader output
1 Incorrect 6 ms 11988 KB Extra information in the output file
2 Halted 0 ms 0 KB -

Subtask #3
0 / 37.0

# Verdict Execution time Memory Grader output
1 Incorrect 6 ms 11988 KB Extra information in the output file
2 Halted 0 ms 0 KB -