oj.uz

Submission #965448

# Submission time Handle Problem Language Result Execution time Memory
965448 2024-04-18T15:09:58 Z pcc Network (BOI15_net) C++17
18 / 100
 5 ms 14168 KB 
#include <bits/stdc++.h>
using namespace std;
 
#define ll long long
#define pll pair<ll,ll>
#define pii pair<int,int>
#define fs first
#define sc second
#define tlll tuple<ll,ll,ll>
 
 
const int mxn = 5e5+10;
vector<int> tree[mxn];
int dfn[mxn],pt;
int N;
vector<pii> ans;
 
void dfs(int now,int par){
	dfn[now] = ++pt;
	for(auto nxt:tree[now]){
		if(nxt == par)continue;
		dfs(nxt,now);
	}
	return;
}
 
 
int main(){
	ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
	cin>>N;
	for(int i = 1;i<N;i++){
		int a,b;
		cin>>a>>b;
		tree[a].push_back(b);
		tree[b].push_back(a);
	}
	dfs(1,1);
	vector<pii> v;
	for(int i = 1;i<=N;i++){
		if(tree[i].size() == 1)v.push_back(pii(dfn[i],i));
	}
	sort(v.begin(),v.end());
	for(int i = 0;i<v.size()/2;i++){
		ans.push_back(pii(v[i].sc,v[i+v.size()/2].sc));
	}
	if(v.size()&1)ans.push_back(pii(v.back().sc,1));
	cout<<ans.size()<<'\n';
	for(auto &i:ans)cout<<i.fs<<' '<<i.sc<<'\n';
	return 0;
}

Compilation message

net.cpp: In function 'int main()':
net.cpp:43:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   43 |  for(int i = 0;i<v.size()/2;i++){
      |                ~^~~~~~~~~~~

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 13912 KB Output is correct
2 Correct 3 ms 13916 KB Output is correct
3 Correct 4 ms 13748 KB Output is correct
4 Correct 4 ms 13916 KB Output is correct
5 Correct 3 ms 13916 KB Output is correct
6 Correct 3 ms 13916 KB Output is correct
7 Correct 3 ms 13912 KB Output is correct
8 Correct 3 ms 13916 KB Output is correct
9 Correct 3 ms 13916 KB Output is correct
10 Correct 3 ms 13916 KB Output is correct
11 Correct 3 ms 13912 KB Output is correct
12 Correct 3 ms 13916 KB Output is correct
13 Correct 4 ms 13916 KB Output is correct
14 Correct 3 ms 13916 KB Output is correct
15 Correct 3 ms 13916 KB Output is correct
16 Correct 3 ms 13916 KB Output is correct
17 Correct 3 ms 13916 KB Output is correct
18 Correct 4 ms 13916 KB Output is correct
19 Correct 3 ms 13916 KB Output is correct
20 Correct 3 ms 14168 KB Output is correct

Subtask #2
0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 13912 KB Output is correct
2 Correct 3 ms 13916 KB Output is correct
3 Correct 4 ms 13748 KB Output is correct
4 Correct 4 ms 13916 KB Output is correct
5 Correct 3 ms 13916 KB Output is correct
6 Correct 3 ms 13916 KB Output is correct
7 Correct 3 ms 13912 KB Output is correct
8 Correct 3 ms 13916 KB Output is correct
9 Correct 3 ms 13916 KB Output is correct
10 Correct 3 ms 13916 KB Output is correct
11 Correct 3 ms 13912 KB Output is correct
12 Correct 3 ms 13916 KB Output is correct
13 Correct 4 ms 13916 KB Output is correct
14 Correct 3 ms 13916 KB Output is correct
15 Correct 3 ms 13916 KB Output is correct
16 Correct 3 ms 13916 KB Output is correct
17 Correct 3 ms 13916 KB Output is correct
18 Correct 4 ms 13916 KB Output is correct
19 Correct 3 ms 13916 KB Output is correct
20 Correct 3 ms 14168 KB Output is correct
21 Correct 3 ms 13916 KB Output is correct
22 Correct 4 ms 13916 KB Output is correct
23 Correct 4 ms 14116 KB Output is correct
24 Correct 4 ms 13992 KB Output is correct
25 Correct 4 ms 13916 KB Output is correct
26 Correct 3 ms 13912 KB Output is correct
27 Correct 4 ms 13916 KB Output is correct
28 Correct 4 ms 13916 KB Output is correct
29 Correct 4 ms 13912 KB Output is correct
30 Correct 3 ms 13912 KB Output is correct
31 Correct 4 ms 13916 KB Output is correct
32 Correct 4 ms 13916 KB Output is correct
33 Incorrect 3 ms 13916 KB Breaking single line is causing network to disconnect.
34 Halted 0 ms 0 KB -

Subtask #3
0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 13912 KB Output is correct
2 Correct 3 ms 13916 KB Output is correct
3 Correct 4 ms 13748 KB Output is correct
4 Correct 4 ms 13916 KB Output is correct
5 Correct 3 ms 13916 KB Output is correct
6 Correct 3 ms 13916 KB Output is correct
7 Correct 3 ms 13912 KB Output is correct
8 Correct 3 ms 13916 KB Output is correct
9 Correct 3 ms 13916 KB Output is correct
10 Correct 3 ms 13916 KB Output is correct
11 Correct 3 ms 13912 KB Output is correct
12 Correct 3 ms 13916 KB Output is correct
13 Correct 4 ms 13916 KB Output is correct
14 Correct 3 ms 13916 KB Output is correct
15 Correct 3 ms 13916 KB Output is correct
16 Correct 3 ms 13916 KB Output is correct
17 Correct 3 ms 13916 KB Output is correct
18 Correct 4 ms 13916 KB Output is correct
19 Correct 3 ms 13916 KB Output is correct
20 Correct 3 ms 14168 KB Output is correct
21 Correct 3 ms 13916 KB Output is correct
22 Correct 4 ms 13916 KB Output is correct
23 Correct 4 ms 14116 KB Output is correct
24 Correct 4 ms 13992 KB Output is correct
25 Correct 4 ms 13916 KB Output is correct
26 Correct 3 ms 13912 KB Output is correct
27 Correct 4 ms 13916 KB Output is correct
28 Correct 4 ms 13916 KB Output is correct
29 Correct 4 ms 13912 KB Output is correct
30 Correct 3 ms 13912 KB Output is correct
31 Correct 4 ms 13916 KB Output is correct
32 Correct 4 ms 13916 KB Output is correct
33 Incorrect 3 ms 13916 KB Breaking single line is causing network to disconnect.
34 Halted 0 ms 0 KB -