Submission #394757

#	Time	Username	Problem	Language	Result	Execution time	Memory
394757		Hossein8320	Network (BOI15_net)	C++17	100 / 100	492 ms	47656 KiB

net

//That's what she said
#include <bits/stdc++.h>
#define int long long
#define pb push_back
#define F first
#define S second
using namespace std;
const int maxn = 5e5 + 9, modn = 1e9 + 7;
int n, m, v, u;
vector <int> barg, adj[maxn];
void dfs(int v, int par)
{
    if(adj[v].size() == 1) barg.pb(v);
    for(auto i : adj[v]) if(i != par) dfs(i, v);
}
int32_t main(){
	ios_base::sync_with_stdio(false);
	cin.tie(0), cout.tie(0);
	cin >> n;
	for(int i = 1; i < n; i++) cin >> v >> u, adj[v].pb(u), adj[u].pb(v);
	dfs(1, 1);
	cout << (barg.size() + 1) / 2 << '\n';
	int s = barg.size() / 2;
	for(int i = 0; i < s; i++) cout << barg[i] << " " << barg[i + s] << '\n';
    if(s != (barg.size() + 1) / 2) cout << barg[2 * s] << " " << barg[0] << '\n';
	return 0;
}

Compilation message (stderr)

net.cpp: In function 'int32_t main()':
net.cpp:25:10: 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]
   25 |     if(s != (barg.size() + 1) / 2) cout << barg[2 * s] << " " << barg[0] << '\n';
      |        ~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 18 / 18
• Subtask 2: 45 / 45
• Subtask 3: 37 / 37