Submission #95927

#	Time	Username	Problem	Language	Result	Execution time	Memory
95927		luciocf	Network (BOI15_net)	C++14	0 / 100	10 ms	12152 KiB

net

#include <bits/stdc++.h>

using namespace std;

const int maxn = 5e5+10;

vector<int> grafo[maxn];

int main(void)
{
	int n;
	cin >> n;

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

		grafo[u].push_back(v);
		grafo[v].push_back(u);
	}

	int ans = 0, first;
	deque<int> leaf;

	for (int i = 1; i <= n; i++)
		if (grafo[i].size() == 1)
			leaf.push_back(i), ans++, first = i;

	cout << (ans+1)/2 << "\n";
	while (leaf.size() > 0)
	{
		if (leaf.size() > 1)
		{
			cout << leaf.back() << " " << leaf.front() << "\n";
			leaf.pop_back(), leaf.pop_front();
		}
		else
		{
			cout << leaf.back() << " " << first << "\n";
			leaf.pop_back();
		}
	}
}

Compilation message (stderr)

net.cpp: In function 'int main()':
net.cpp:40:43: warning: 'first' may be used uninitialized in this function [-Wmaybe-uninitialized]
    cout << leaf.back() << " " << first << "\n";
                                           ^~~~

• Subtask 1: 0 / 18
• Subtask 2: 0 / 45
• Subtask 3: 0 / 37