# |
Submission time |
Handle |
Problem |
Language |
Result |
Execution time |
Memory |
639532 |
2022-09-10T13:39:20 Z |
zordeno |
Network (BOI15_net) |
C++17 |
|
5 ms |
12128 KB |
#include <bits/stdc++.h>
using namespace std;
#define endl '\n'
#define ll long long
const ll MOD = 1e9 + 7, MAX = 5e5 + 5, INF = 1e18;
vector <int> dx = { 1, 0, 0, -1, 1, 1, -1, -1 };
vector <int> dy = { 0, 1, -1, 0, -1, 1, 1, -1 };
ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; }
ll lcm(ll a, ll b) { return (a / gcd(a, b)) * b; }
vector <ll> adj[MAX];
vector <bool> vis(MAX);
vector <ll> ans;
void dfs(ll node)
{
if (adj[node].size() == 1)
{
ans.push_back(node);
}
vis[node] = true;
for (auto child : adj[node])
{
if (!vis[child])
{
dfs(child);
}
}
}
int main()
{
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
//freopen("", "r", stdin);
//freopen("", "w", stdout);
ll n;
cin >> n;
for (ll i = 0; i < n - 1; i++)
{
ll u, v;
cin >> u >> v;
u--, v--;
adj[u].push_back(v);
adj[v].push_back(u);
}
dfs(0);
cout << ceil(ans.size() * 1.0 / 2.0) << endl;
for (ll i = 0; i < ans.size() / 2; i++)
{
cout << ans[i] + 1 << " " << ans[ans.size() - i - 1] + 1 << endl;
}
if (ans.size() % 2 != 0)
{
cout << ans[ans.size() / 2] + 1 << " 1" << endl;
}
}
Compilation message
net.cpp: In function 'int main()':
net.cpp:51:19: 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]
51 | for (ll i = 0; i < ans.size() / 2; i++)
| ~~^~~~~~~~~~~~~~~~
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
5 ms |
12116 KB |
Output is correct |
2 |
Incorrect |
5 ms |
12128 KB |
Breaking single line is causing network to disconnect. |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
5 ms |
12116 KB |
Output is correct |
2 |
Incorrect |
5 ms |
12128 KB |
Breaking single line is causing network to disconnect. |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
5 ms |
12116 KB |
Output is correct |
2 |
Incorrect |
5 ms |
12128 KB |
Breaking single line is causing network to disconnect. |
3 |
Halted |
0 ms |
0 KB |
- |