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Submission #356171

# Submission time Handle Problem Language Result Execution time Memory
356171 2021-01-23T07:55:15 Z nikita4109 Network (BOI15_net) C++17
0 / 100
 10 ms 12140 KB 
#include <bits/stdc++.h>

using namespace std;

random_device rd;
mt19937 rnd(rd());
#define pt pair<int, int>
#define x first
#define y second
#define what_is(x) cerr << #x << " is " << x << endl;
#define ok cerr << "ok" << endl;
#define endl '\n'
#define int long long
#define ld long double

const int N = 5e5 + 5;

vector<int> g[N];

signed main()
{
	cin.tie(0), cout.tie(0), ios::sync_with_stdio(0);

	int n;
	cin >> n;
	for (int i = 0, x, y; i < n - 1; ++i)
	{
		cin >> x >> y;
		--x, --y;
		g[x].push_back(y);
		g[y].push_back(x);
	}

	vector<int> leaves;
	for (int i = 0; i < n; ++i)
		if (g[i].size() == 1)
			leaves.push_back(i + 1);

	int c = leaves.size();
	cout << (c + 1) / 2 << endl;
	for (int i = 0; i + 2 < c; i += 2)
		cout << leaves[i] << " " << leaves[i + 1] << endl;

	if (c % 2)
		cout << leaves[0] << " " << leaves.back() << endl;

	return 0;
}

Subtask #1
0 / 18.0

# Verdict Execution time Memory Grader output
1 Incorrect 10 ms 12140 KB Unexpected end of file - int32 expected
2 Halted 0 ms 0 KB -

Subtask #2
0 / 45.0

# Verdict Execution time Memory Grader output
1 Incorrect 10 ms 12140 KB Unexpected end of file - int32 expected
2 Halted 0 ms 0 KB -

Subtask #3
0 / 37.0

# Verdict Execution time Memory Grader output
1 Incorrect 10 ms 12140 KB Unexpected end of file - int32 expected
2 Halted 0 ms 0 KB -