| # |
Submission time |
Handle |
Problem |
Language |
Result |
Execution time |
Memory |
| 932596 |
2024-02-23T19:49:11 Z |
vjudge1 |
Network (BOI15_net) |
C++17 |
|
1 ms |
512 KB |
// in the name of God
#include<bits/stdc++.h>
using namespace std;
#define int long long
#define fast() ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define ff first
#define ss second
#define pb(x) push_back(x)
#define all(x) x.begin(), x.end()
#define mk make_pair
#define ppb pop_back
#define endl '\n'
#define pii pair<int, int>
#define sz(x) (int)x.size()
#define file() freopen("input.txt", "r", stdin);
#pragma GCC optimize("Ofast")
#pragma GCC optimize("O4")
#pragma GCC optimize("unroll-loops")
//#pragma GCC target("avx2")
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int mod = 1e9 + 7, maxn = 2e3 + 10, sq = 3163, inf = 1e18 + 10, lg = 25, pp = 4447, modd = 1e9 + 9;
int n;
vector<vector<int>> g(maxn);
int h[maxn];
void dfs(int u = 0, int parr = -1){
for(int v : g[u]){
if(v != parr){
h[v] = h[u] + 1;
dfs(v, u);
}
}
}
bool cmp(int a, int b){
if(h[a] > h[b]) return a > b;
return a < b;
}
signed main(){
fast();//file();
cin >> n;
for(int i = 1; i < n; ++i){
int u, v; cin >> u >> v;
u--; v--;
g[u].pb(v);
g[v].pb(u);
}
dfs();
vector<int> b;
for(int i = 0; i < n; ++i) if(g[i].size() == 1) b.pb(i);
cout << ceil((double) b.size() / 2) << endl;
sort(all(b), cmp);
int p1 = 0, p2 = b.size() - 1;
while(p1 < p2){
cout << b[p1] + 1 << " " << b[p2] + 1 << endl;
p1++;
p2--;
}
if(b.size() % 2){
cout << b[b.size() / 2] + 1 << " " << b.back() + 1;
}
}
// Running from the daylight...
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
348 KB |
Output is correct |
| 2 |
Correct |
0 ms |
348 KB |
Output is correct |
| 3 |
Correct |
1 ms |
348 KB |
Output is correct |
| 4 |
Correct |
0 ms |
348 KB |
Output is correct |
| 5 |
Correct |
0 ms |
348 KB |
Output is correct |
| 6 |
Correct |
0 ms |
348 KB |
Output is correct |
| 7 |
Correct |
0 ms |
348 KB |
Output is correct |
| 8 |
Correct |
0 ms |
348 KB |
Output is correct |
| 9 |
Correct |
1 ms |
344 KB |
Output is correct |
| 10 |
Correct |
0 ms |
344 KB |
Output is correct |
| 11 |
Correct |
0 ms |
512 KB |
Output is correct |
| 12 |
Correct |
0 ms |
348 KB |
Output is correct |
| 13 |
Correct |
0 ms |
348 KB |
Output is correct |
| 14 |
Correct |
0 ms |
348 KB |
Output is correct |
| 15 |
Correct |
1 ms |
344 KB |
Output is correct |
| 16 |
Correct |
0 ms |
348 KB |
Output is correct |
| 17 |
Correct |
0 ms |
348 KB |
Output is correct |
| 18 |
Incorrect |
0 ms |
348 KB |
Breaking single line is causing network to disconnect. |
| 19 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
348 KB |
Output is correct |
| 2 |
Correct |
0 ms |
348 KB |
Output is correct |
| 3 |
Correct |
1 ms |
348 KB |
Output is correct |
| 4 |
Correct |
0 ms |
348 KB |
Output is correct |
| 5 |
Correct |
0 ms |
348 KB |
Output is correct |
| 6 |
Correct |
0 ms |
348 KB |
Output is correct |
| 7 |
Correct |
0 ms |
348 KB |
Output is correct |
| 8 |
Correct |
0 ms |
348 KB |
Output is correct |
| 9 |
Correct |
1 ms |
344 KB |
Output is correct |
| 10 |
Correct |
0 ms |
344 KB |
Output is correct |
| 11 |
Correct |
0 ms |
512 KB |
Output is correct |
| 12 |
Correct |
0 ms |
348 KB |
Output is correct |
| 13 |
Correct |
0 ms |
348 KB |
Output is correct |
| 14 |
Correct |
0 ms |
348 KB |
Output is correct |
| 15 |
Correct |
1 ms |
344 KB |
Output is correct |
| 16 |
Correct |
0 ms |
348 KB |
Output is correct |
| 17 |
Correct |
0 ms |
348 KB |
Output is correct |
| 18 |
Incorrect |
0 ms |
348 KB |
Breaking single line is causing network to disconnect. |
| 19 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
348 KB |
Output is correct |
| 2 |
Correct |
0 ms |
348 KB |
Output is correct |
| 3 |
Correct |
1 ms |
348 KB |
Output is correct |
| 4 |
Correct |
0 ms |
348 KB |
Output is correct |
| 5 |
Correct |
0 ms |
348 KB |
Output is correct |
| 6 |
Correct |
0 ms |
348 KB |
Output is correct |
| 7 |
Correct |
0 ms |
348 KB |
Output is correct |
| 8 |
Correct |
0 ms |
348 KB |
Output is correct |
| 9 |
Correct |
1 ms |
344 KB |
Output is correct |
| 10 |
Correct |
0 ms |
344 KB |
Output is correct |
| 11 |
Correct |
0 ms |
512 KB |
Output is correct |
| 12 |
Correct |
0 ms |
348 KB |
Output is correct |
| 13 |
Correct |
0 ms |
348 KB |
Output is correct |
| 14 |
Correct |
0 ms |
348 KB |
Output is correct |
| 15 |
Correct |
1 ms |
344 KB |
Output is correct |
| 16 |
Correct |
0 ms |
348 KB |
Output is correct |
| 17 |
Correct |
0 ms |
348 KB |
Output is correct |
| 18 |
Incorrect |
0 ms |
348 KB |
Breaking single line is causing network to disconnect. |
| 19 |
Halted |
0 ms |
0 KB |
- |
