Submission #75935

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
75935	2018-09-11T15:47:21 Z	Vasiljko	Network (BOI15_net)	C++14	63 / 100	11 ms	10916 KB

#include <bits/stdc++.h>
using namespace std;

const int N = 200000+10;
vector<int>leaf;
vector<int>v[N];
void dfs(int s,int p){
	if(v[s].size()==1){
		leaf.push_back(s);
	}
	for(int i=0;i<v[s].size();i++){
		if(v[s][i]!=p){
			dfs(v[s][i],s);
		}
	}
}

int main() {
	ios_base::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);
	
	int n,x,y;
	cin>>n;
	for(int i=0;i<n-1;i++){
		cin>>x>>y;
		v[x].push_back(y);
		v[y].push_back(x);
	}
	if(n==1){
		cout<<1<<endl<<1<<" "<<1;
		return 0;
	}
	dfs(1,-1);
	int k=(int)leaf.size();
	if(k%2==0){
		cout<<k/2<<"\n";
		for(int i=0;i<k/2;i++){
			cout<<leaf[i]<<" "<<leaf[i+k/2]<<"\n";
		}
	}else{
		cout<<k/2+1<<"\n";
		for(int i=0;i<k/2;i++){
			cout<<leaf[i]<<" "<<leaf[i+k/2+1]<<"\n";
		}
		cout<<leaf[k/2]<<" "<<1;
	}
	
	return 0;
}

Compilation message

net.cpp: In function 'void dfs(int, int)':
net.cpp:11:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<v[s].size();i++){
              ~^~~~~~~~~~~~

Subtask #1
18.0 / 18.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	6 ms	4984 KB	Output is correct
2	Correct	7 ms	5112 KB	Output is correct
3	Correct	6 ms	5276 KB	Output is correct
4	Correct	7 ms	5276 KB	Output is correct
5	Correct	7 ms	5276 KB	Output is correct
6	Correct	6 ms	5276 KB	Output is correct
7	Correct	6 ms	5276 KB	Output is correct
8	Correct	8 ms	5276 KB	Output is correct
9	Correct	7 ms	5308 KB	Output is correct
10	Correct	7 ms	5308 KB	Output is correct
11	Correct	6 ms	5308 KB	Output is correct
12	Correct	6 ms	5348 KB	Output is correct
13	Correct	7 ms	5460 KB	Output is correct
14	Correct	7 ms	5460 KB	Output is correct
15	Correct	7 ms	5460 KB	Output is correct
16	Correct	6 ms	5472 KB	Output is correct
17	Correct	7 ms	5472 KB	Output is correct
18	Correct	6 ms	5472 KB	Output is correct
19	Correct	6 ms	5472 KB	Output is correct
20	Correct	6 ms	5520 KB	Output is correct

Subtask #2
45.0 / 45.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	6 ms	4984 KB	Output is correct
2	Correct	7 ms	5112 KB	Output is correct
3	Correct	6 ms	5276 KB	Output is correct
4	Correct	7 ms	5276 KB	Output is correct
5	Correct	7 ms	5276 KB	Output is correct
6	Correct	6 ms	5276 KB	Output is correct
7	Correct	6 ms	5276 KB	Output is correct
8	Correct	8 ms	5276 KB	Output is correct
9	Correct	7 ms	5308 KB	Output is correct
10	Correct	7 ms	5308 KB	Output is correct
11	Correct	6 ms	5308 KB	Output is correct
12	Correct	6 ms	5348 KB	Output is correct
13	Correct	7 ms	5460 KB	Output is correct
14	Correct	7 ms	5460 KB	Output is correct
15	Correct	7 ms	5460 KB	Output is correct
16	Correct	6 ms	5472 KB	Output is correct
17	Correct	7 ms	5472 KB	Output is correct
18	Correct	6 ms	5472 KB	Output is correct
19	Correct	6 ms	5472 KB	Output is correct
20	Correct	6 ms	5520 KB	Output is correct
21	Correct	6 ms	5524 KB	Output is correct
22	Correct	8 ms	5740 KB	Output is correct
23	Correct	7 ms	5740 KB	Output is correct
24	Correct	7 ms	5740 KB	Output is correct
25	Correct	7 ms	5876 KB	Output is correct
26	Correct	7 ms	5904 KB	Output is correct
27	Correct	7 ms	5916 KB	Output is correct
28	Correct	7 ms	6080 KB	Output is correct
29	Correct	7 ms	6080 KB	Output is correct
30	Correct	6 ms	6080 KB	Output is correct
31	Correct	8 ms	6080 KB	Output is correct
32	Correct	6 ms	6080 KB	Output is correct
33	Correct	6 ms	6080 KB	Output is correct
34	Correct	8 ms	6080 KB	Output is correct
35	Correct	7 ms	6080 KB	Output is correct
36	Correct	6 ms	6080 KB	Output is correct
37	Correct	7 ms	6080 KB	Output is correct
38	Correct	7 ms	6172 KB	Output is correct
39	Correct	6 ms	6172 KB	Output is correct
40	Correct	6 ms	6172 KB	Output is correct
41	Correct	7 ms	6172 KB	Output is correct
42	Correct	6 ms	6172 KB	Output is correct
43	Correct	7 ms	6172 KB	Output is correct
44	Correct	6 ms	6172 KB	Output is correct
45	Correct	7 ms	6172 KB	Output is correct
46	Correct	7 ms	6172 KB	Output is correct
47	Correct	6 ms	6172 KB	Output is correct
48	Correct	6 ms	6172 KB	Output is correct
49	Correct	8 ms	6172 KB	Output is correct
50	Correct	7 ms	6172 KB	Output is correct
51	Correct	6 ms	6172 KB	Output is correct
52	Correct	6 ms	6172 KB	Output is correct
53	Correct	6 ms	6172 KB	Output is correct
54	Correct	7 ms	6172 KB	Output is correct
55	Correct	7 ms	6172 KB	Output is correct
56	Correct	7 ms	6172 KB	Output is correct
57	Correct	6 ms	6172 KB	Output is correct
58	Correct	7 ms	6172 KB	Output is correct

Subtask #3
0 / 37.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	6 ms	4984 KB	Output is correct
2	Correct	7 ms	5112 KB	Output is correct
3	Correct	6 ms	5276 KB	Output is correct
4	Correct	7 ms	5276 KB	Output is correct
5	Correct	7 ms	5276 KB	Output is correct
6	Correct	6 ms	5276 KB	Output is correct
7	Correct	6 ms	5276 KB	Output is correct
8	Correct	8 ms	5276 KB	Output is correct
9	Correct	7 ms	5308 KB	Output is correct
10	Correct	7 ms	5308 KB	Output is correct
11	Correct	6 ms	5308 KB	Output is correct
12	Correct	6 ms	5348 KB	Output is correct
13	Correct	7 ms	5460 KB	Output is correct
14	Correct	7 ms	5460 KB	Output is correct
15	Correct	7 ms	5460 KB	Output is correct
16	Correct	6 ms	5472 KB	Output is correct
17	Correct	7 ms	5472 KB	Output is correct
18	Correct	6 ms	5472 KB	Output is correct
19	Correct	6 ms	5472 KB	Output is correct
20	Correct	6 ms	5520 KB	Output is correct
21	Correct	6 ms	5524 KB	Output is correct
22	Correct	8 ms	5740 KB	Output is correct
23	Correct	7 ms	5740 KB	Output is correct
24	Correct	7 ms	5740 KB	Output is correct
25	Correct	7 ms	5876 KB	Output is correct
26	Correct	7 ms	5904 KB	Output is correct
27	Correct	7 ms	5916 KB	Output is correct
28	Correct	7 ms	6080 KB	Output is correct
29	Correct	7 ms	6080 KB	Output is correct
30	Correct	6 ms	6080 KB	Output is correct
31	Correct	8 ms	6080 KB	Output is correct
32	Correct	6 ms	6080 KB	Output is correct
33	Correct	6 ms	6080 KB	Output is correct
34	Correct	8 ms	6080 KB	Output is correct
35	Correct	7 ms	6080 KB	Output is correct
36	Correct	6 ms	6080 KB	Output is correct
37	Correct	7 ms	6080 KB	Output is correct
38	Correct	7 ms	6172 KB	Output is correct
39	Correct	6 ms	6172 KB	Output is correct
40	Correct	6 ms	6172 KB	Output is correct
41	Correct	7 ms	6172 KB	Output is correct
42	Correct	6 ms	6172 KB	Output is correct
43	Correct	7 ms	6172 KB	Output is correct
44	Correct	6 ms	6172 KB	Output is correct
45	Correct	7 ms	6172 KB	Output is correct
46	Correct	7 ms	6172 KB	Output is correct
47	Correct	6 ms	6172 KB	Output is correct
48	Correct	6 ms	6172 KB	Output is correct
49	Correct	8 ms	6172 KB	Output is correct
50	Correct	7 ms	6172 KB	Output is correct
51	Correct	6 ms	6172 KB	Output is correct
52	Correct	6 ms	6172 KB	Output is correct
53	Correct	6 ms	6172 KB	Output is correct
54	Correct	7 ms	6172 KB	Output is correct
55	Correct	7 ms	6172 KB	Output is correct
56	Correct	7 ms	6172 KB	Output is correct
57	Correct	6 ms	6172 KB	Output is correct
58	Correct	7 ms	6172 KB	Output is correct
59	Runtime error	11 ms	10916 KB	Execution killed with signal 11 (could be triggered by violating memory limits)
60	Halted	0 ms	0 KB	-

Submission #75935

Compilation message

Subtask #1 18.0 / 18.0

Subtask #2 45.0 / 45.0

Subtask #3 0 / 37.0

Subtask #1
18.0 / 18.0

Subtask #2
45.0 / 45.0

Subtask #3
0 / 37.0