| # |
Submission time |
Handle |
Problem |
Language |
Result |
Execution time |
Memory |
| 933686 |
2024-02-26T05:27:28 Z |
oblantis |
Network (BOI15_net) |
C++17 |
|
5 ms |
12172 KB |
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#pragma GCC optimize("O3,unroll-loops")
#include <bits/stdc++.h>
#define all(v) v.begin(), v.end()
#define pb push_back
#define ss second
#define ff first
#define vt vector
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
const int inf = 1e9;
const int mod = 1e9+7;
const int maxn = 5e5 + 1;
vt<pii> ans;
vt<int> g[maxn];
pii dfs(int v, int p){
int pr = -1, rp = -1;
if(g[v].size() == 1)pr = v;
for(auto i : g[v]){
if(i == p)continue;
pii wt = dfs(i, v);
if(pr == -1)pr = wt.ff;
else if(wt.ff != -1){
if(rp == -1)rp = wt.ff;
else {
ans.pb({rp, wt.ff});
rp = -1;
}
}
if(wt.ss != -1){
if(rp == -1)rp = wt.ss;
else {
ans.pb({rp, wt.ss});
rp = -1;
}
}
}
return {pr, rp};
}
void solve() {
int n;
cin >> n;
for(int i = 0, u, v; i < n - 1; i++){
cin >> u >> v;
g[u].pb(v), g[v].pb(u);
}
int t = 1;
for(int i = 1; i <= n; i++)if((int)g[i].size() > 1)t = i;
pii wt = dfs(t, 0);
if(wt.ss != -1)ans.pb({wt.ff, wt.ss});
else ans.pb({wt.ff, wt.ff % n + 1});
cout << ans.size() << '\n';
for(auto i : ans)cout << i.ff << ' ' << i.ss << '\n';
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
int times = 1;
//cin >> times;
for(int i = 1; i <= times; i++) {
solve();
}
return 0;
}
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
4 ms |
12120 KB |
Output is correct |
| 2 |
Correct |
4 ms |
12120 KB |
Output is correct |
| 3 |
Correct |
4 ms |
12124 KB |
Output is correct |
| 4 |
Correct |
4 ms |
12172 KB |
Output is correct |
| 5 |
Correct |
4 ms |
12120 KB |
Output is correct |
| 6 |
Correct |
5 ms |
12124 KB |
Output is correct |
| 7 |
Incorrect |
4 ms |
12124 KB |
Breaking single line is causing network to disconnect. |
| 8 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
4 ms |
12120 KB |
Output is correct |
| 2 |
Correct |
4 ms |
12120 KB |
Output is correct |
| 3 |
Correct |
4 ms |
12124 KB |
Output is correct |
| 4 |
Correct |
4 ms |
12172 KB |
Output is correct |
| 5 |
Correct |
4 ms |
12120 KB |
Output is correct |
| 6 |
Correct |
5 ms |
12124 KB |
Output is correct |
| 7 |
Incorrect |
4 ms |
12124 KB |
Breaking single line is causing network to disconnect. |
| 8 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
4 ms |
12120 KB |
Output is correct |
| 2 |
Correct |
4 ms |
12120 KB |
Output is correct |
| 3 |
Correct |
4 ms |
12124 KB |
Output is correct |
| 4 |
Correct |
4 ms |
12172 KB |
Output is correct |
| 5 |
Correct |
4 ms |
12120 KB |
Output is correct |
| 6 |
Correct |
5 ms |
12124 KB |
Output is correct |
| 7 |
Incorrect |
4 ms |
12124 KB |
Breaking single line is causing network to disconnect. |
| 8 |
Halted |
0 ms |
0 KB |
- |
