Submission #75941

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
75941	2018-09-11T15:54:49 Z	Vasiljko	Network (BOI15_net)	C++14	100 / 100	572 ms	43052 KB

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

typedef long long ll;
const ll MOD = 1e9+7;
const int N = 5e5+5;

int n;
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 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);
	}

	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:16:15: 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	12 ms	12024 KB	Output is correct
2	Correct	13 ms	12156 KB	Output is correct
3	Correct	12 ms	12200 KB	Output is correct
4	Correct	13 ms	12200 KB	Output is correct
5	Correct	12 ms	12304 KB	Output is correct
6	Correct	13 ms	12340 KB	Output is correct
7	Correct	12 ms	12340 KB	Output is correct
8	Correct	15 ms	12340 KB	Output is correct
9	Correct	12 ms	12340 KB	Output is correct
10	Correct	12 ms	12340 KB	Output is correct
11	Correct	12 ms	12376 KB	Output is correct
12	Correct	14 ms	12376 KB	Output is correct
13	Correct	12 ms	12376 KB	Output is correct
14	Correct	12 ms	12376 KB	Output is correct
15	Correct	12 ms	12376 KB	Output is correct
16	Correct	13 ms	12376 KB	Output is correct
17	Correct	13 ms	12376 KB	Output is correct
18	Correct	13 ms	12376 KB	Output is correct
19	Correct	15 ms	12376 KB	Output is correct
20	Correct	13 ms	12376 KB	Output is correct

Subtask #2
45.0 / 45.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	12 ms	12024 KB	Output is correct
2	Correct	13 ms	12156 KB	Output is correct
3	Correct	12 ms	12200 KB	Output is correct
4	Correct	13 ms	12200 KB	Output is correct
5	Correct	12 ms	12304 KB	Output is correct
6	Correct	13 ms	12340 KB	Output is correct
7	Correct	12 ms	12340 KB	Output is correct
8	Correct	15 ms	12340 KB	Output is correct
9	Correct	12 ms	12340 KB	Output is correct
10	Correct	12 ms	12340 KB	Output is correct
11	Correct	12 ms	12376 KB	Output is correct
12	Correct	14 ms	12376 KB	Output is correct
13	Correct	12 ms	12376 KB	Output is correct
14	Correct	12 ms	12376 KB	Output is correct
15	Correct	12 ms	12376 KB	Output is correct
16	Correct	13 ms	12376 KB	Output is correct
17	Correct	13 ms	12376 KB	Output is correct
18	Correct	13 ms	12376 KB	Output is correct
19	Correct	15 ms	12376 KB	Output is correct
20	Correct	13 ms	12376 KB	Output is correct
21	Correct	13 ms	12460 KB	Output is correct
22	Correct	13 ms	12460 KB	Output is correct
23	Correct	13 ms	12608 KB	Output is correct
24	Correct	14 ms	12608 KB	Output is correct
25	Correct	13 ms	12608 KB	Output is correct
26	Correct	13 ms	12608 KB	Output is correct
27	Correct	14 ms	12608 KB	Output is correct
28	Correct	13 ms	12612 KB	Output is correct
29	Correct	14 ms	12632 KB	Output is correct
30	Correct	14 ms	12632 KB	Output is correct
31	Correct	14 ms	12668 KB	Output is correct
32	Correct	12 ms	12668 KB	Output is correct
33	Correct	12 ms	12668 KB	Output is correct
34	Correct	12 ms	12668 KB	Output is correct
35	Correct	12 ms	12668 KB	Output is correct
36	Correct	13 ms	12668 KB	Output is correct
37	Correct	12 ms	12708 KB	Output is correct
38	Correct	13 ms	12716 KB	Output is correct
39	Correct	12 ms	12716 KB	Output is correct
40	Correct	12 ms	12716 KB	Output is correct
41	Correct	13 ms	12716 KB	Output is correct
42	Correct	12 ms	12716 KB	Output is correct
43	Correct	13 ms	12744 KB	Output is correct
44	Correct	13 ms	12744 KB	Output is correct
45	Correct	13 ms	12744 KB	Output is correct
46	Correct	12 ms	12756 KB	Output is correct
47	Correct	11 ms	12756 KB	Output is correct
48	Correct	12 ms	12756 KB	Output is correct
49	Correct	13 ms	12772 KB	Output is correct
50	Correct	12 ms	12772 KB	Output is correct
51	Correct	14 ms	12788 KB	Output is correct
52	Correct	12 ms	12792 KB	Output is correct
53	Correct	13 ms	12796 KB	Output is correct
54	Correct	12 ms	12796 KB	Output is correct
55	Correct	12 ms	12796 KB	Output is correct
56	Correct	13 ms	12796 KB	Output is correct
57	Correct	12 ms	12820 KB	Output is correct
58	Correct	13 ms	12820 KB	Output is correct

Subtask #3
37.0 / 37.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	12 ms	12024 KB	Output is correct
2	Correct	13 ms	12156 KB	Output is correct
3	Correct	12 ms	12200 KB	Output is correct
4	Correct	13 ms	12200 KB	Output is correct
5	Correct	12 ms	12304 KB	Output is correct
6	Correct	13 ms	12340 KB	Output is correct
7	Correct	12 ms	12340 KB	Output is correct
8	Correct	15 ms	12340 KB	Output is correct
9	Correct	12 ms	12340 KB	Output is correct
10	Correct	12 ms	12340 KB	Output is correct
11	Correct	12 ms	12376 KB	Output is correct
12	Correct	14 ms	12376 KB	Output is correct
13	Correct	12 ms	12376 KB	Output is correct
14	Correct	12 ms	12376 KB	Output is correct
15	Correct	12 ms	12376 KB	Output is correct
16	Correct	13 ms	12376 KB	Output is correct
17	Correct	13 ms	12376 KB	Output is correct
18	Correct	13 ms	12376 KB	Output is correct
19	Correct	15 ms	12376 KB	Output is correct
20	Correct	13 ms	12376 KB	Output is correct
21	Correct	13 ms	12460 KB	Output is correct
22	Correct	13 ms	12460 KB	Output is correct
23	Correct	13 ms	12608 KB	Output is correct
24	Correct	14 ms	12608 KB	Output is correct
25	Correct	13 ms	12608 KB	Output is correct
26	Correct	13 ms	12608 KB	Output is correct
27	Correct	14 ms	12608 KB	Output is correct
28	Correct	13 ms	12612 KB	Output is correct
29	Correct	14 ms	12632 KB	Output is correct
30	Correct	14 ms	12632 KB	Output is correct
31	Correct	14 ms	12668 KB	Output is correct
32	Correct	12 ms	12668 KB	Output is correct
33	Correct	12 ms	12668 KB	Output is correct
34	Correct	12 ms	12668 KB	Output is correct
35	Correct	12 ms	12668 KB	Output is correct
36	Correct	13 ms	12668 KB	Output is correct
37	Correct	12 ms	12708 KB	Output is correct
38	Correct	13 ms	12716 KB	Output is correct
39	Correct	12 ms	12716 KB	Output is correct
40	Correct	12 ms	12716 KB	Output is correct
41	Correct	13 ms	12716 KB	Output is correct
42	Correct	12 ms	12716 KB	Output is correct
43	Correct	13 ms	12744 KB	Output is correct
44	Correct	13 ms	12744 KB	Output is correct
45	Correct	13 ms	12744 KB	Output is correct
46	Correct	12 ms	12756 KB	Output is correct
47	Correct	11 ms	12756 KB	Output is correct
48	Correct	12 ms	12756 KB	Output is correct
49	Correct	13 ms	12772 KB	Output is correct
50	Correct	12 ms	12772 KB	Output is correct
51	Correct	14 ms	12788 KB	Output is correct
52	Correct	12 ms	12792 KB	Output is correct
53	Correct	13 ms	12796 KB	Output is correct
54	Correct	12 ms	12796 KB	Output is correct
55	Correct	12 ms	12796 KB	Output is correct
56	Correct	13 ms	12796 KB	Output is correct
57	Correct	12 ms	12820 KB	Output is correct
58	Correct	13 ms	12820 KB	Output is correct
59	Correct	437 ms	32012 KB	Output is correct
60	Correct	517 ms	34096 KB	Output is correct
61	Correct	15 ms	34096 KB	Output is correct
62	Correct	17 ms	34096 KB	Output is correct
63	Correct	451 ms	34096 KB	Output is correct
64	Correct	16 ms	34096 KB	Output is correct
65	Correct	37 ms	34096 KB	Output is correct
66	Correct	185 ms	34096 KB	Output is correct
67	Correct	572 ms	42432 KB	Output is correct
68	Correct	556 ms	43052 KB	Output is correct
69	Correct	19 ms	43052 KB	Output is correct
70	Correct	96 ms	43052 KB	Output is correct
71	Correct	387 ms	43052 KB	Output is correct
72	Correct	380 ms	43052 KB	Output is correct
73	Correct	89 ms	43052 KB	Output is correct
74	Correct	518 ms	43052 KB	Output is correct
75	Correct	38 ms	43052 KB	Output is correct
76	Correct	357 ms	43052 KB	Output is correct
77	Correct	391 ms	43052 KB	Output is correct
78	Correct	48 ms	43052 KB	Output is correct
79	Correct	567 ms	43052 KB	Output is correct
80	Correct	16 ms	43052 KB	Output is correct
81	Correct	124 ms	43052 KB	Output is correct
82	Correct	452 ms	43052 KB	Output is correct
83	Correct	498 ms	43052 KB	Output is correct
84	Correct	506 ms	43052 KB	Output is correct
85	Correct	522 ms	43052 KB	Output is correct
86	Correct	552 ms	43052 KB	Output is correct
87	Correct	516 ms	43052 KB	Output is correct

Submission #75941

Compilation message

Subtask #1 18.0 / 18.0

Subtask #2 45.0 / 45.0

Subtask #3 37.0 / 37.0

Subtask #1
18.0 / 18.0

Subtask #2
45.0 / 45.0

Subtask #3
37.0 / 37.0