Submission #538944

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
538944	2022-03-18T05:17:02 Z	Soul234	Network (BOI15_net)	C++14	100 / 100	482 ms	47744 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 of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   16 |  for(int i=0;i<v[s].size();i++){
      |              ~^~~~~~~~~~~~

Subtask #1
18.0 / 18.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	9 ms	11988 KB	Output is correct
2	Correct	8 ms	11988 KB	Output is correct
3	Correct	8 ms	11988 KB	Output is correct
4	Correct	10 ms	12012 KB	Output is correct
5	Correct	7 ms	11988 KB	Output is correct
6	Correct	10 ms	11988 KB	Output is correct
7	Correct	7 ms	11988 KB	Output is correct
8	Correct	7 ms	11988 KB	Output is correct
9	Correct	7 ms	11988 KB	Output is correct
10	Correct	8 ms	11988 KB	Output is correct
11	Correct	8 ms	11988 KB	Output is correct
12	Correct	7 ms	11972 KB	Output is correct
13	Correct	8 ms	11988 KB	Output is correct
14	Correct	7 ms	11988 KB	Output is correct
15	Correct	7 ms	11988 KB	Output is correct
16	Correct	6 ms	12068 KB	Output is correct
17	Correct	8 ms	12060 KB	Output is correct
18	Correct	7 ms	11956 KB	Output is correct
19	Correct	7 ms	11988 KB	Output is correct
20	Correct	6 ms	11988 KB	Output is correct

Subtask #2
45.0 / 45.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	9 ms	11988 KB	Output is correct
2	Correct	8 ms	11988 KB	Output is correct
3	Correct	8 ms	11988 KB	Output is correct
4	Correct	10 ms	12012 KB	Output is correct
5	Correct	7 ms	11988 KB	Output is correct
6	Correct	10 ms	11988 KB	Output is correct
7	Correct	7 ms	11988 KB	Output is correct
8	Correct	7 ms	11988 KB	Output is correct
9	Correct	7 ms	11988 KB	Output is correct
10	Correct	8 ms	11988 KB	Output is correct
11	Correct	8 ms	11988 KB	Output is correct
12	Correct	7 ms	11972 KB	Output is correct
13	Correct	8 ms	11988 KB	Output is correct
14	Correct	7 ms	11988 KB	Output is correct
15	Correct	7 ms	11988 KB	Output is correct
16	Correct	6 ms	12068 KB	Output is correct
17	Correct	8 ms	12060 KB	Output is correct
18	Correct	7 ms	11956 KB	Output is correct
19	Correct	7 ms	11988 KB	Output is correct
20	Correct	6 ms	11988 KB	Output is correct
21	Correct	7 ms	11988 KB	Output is correct
22	Correct	8 ms	12116 KB	Output is correct
23	Correct	8 ms	12076 KB	Output is correct
24	Correct	8 ms	12112 KB	Output is correct
25	Correct	8 ms	12116 KB	Output is correct
26	Correct	7 ms	12116 KB	Output is correct
27	Correct	7 ms	12116 KB	Output is correct
28	Correct	7 ms	12116 KB	Output is correct
29	Correct	7 ms	12116 KB	Output is correct
30	Correct	6 ms	11988 KB	Output is correct
31	Correct	8 ms	12116 KB	Output is correct
32	Correct	7 ms	11988 KB	Output is correct
33	Correct	7 ms	11988 KB	Output is correct
34	Correct	7 ms	11988 KB	Output is correct
35	Correct	7 ms	12060 KB	Output is correct
36	Correct	7 ms	11988 KB	Output is correct
37	Correct	7 ms	12064 KB	Output is correct
38	Correct	9 ms	12068 KB	Output is correct
39	Correct	8 ms	11988 KB	Output is correct
40	Correct	7 ms	11988 KB	Output is correct
41	Correct	7 ms	11988 KB	Output is correct
42	Correct	8 ms	11988 KB	Output is correct
43	Correct	7 ms	12116 KB	Output is correct
44	Correct	7 ms	11988 KB	Output is correct
45	Correct	7 ms	12064 KB	Output is correct
46	Correct	7 ms	11988 KB	Output is correct
47	Correct	9 ms	12064 KB	Output is correct
48	Correct	9 ms	12008 KB	Output is correct
49	Correct	8 ms	12116 KB	Output is correct
50	Correct	7 ms	12024 KB	Output is correct
51	Correct	7 ms	12068 KB	Output is correct
52	Correct	8 ms	12060 KB	Output is correct
53	Correct	9 ms	12072 KB	Output is correct
54	Correct	9 ms	11968 KB	Output is correct
55	Correct	7 ms	12064 KB	Output is correct
56	Correct	7 ms	12072 KB	Output is correct
57	Correct	7 ms	11988 KB	Output is correct
58	Correct	9 ms	12072 KB	Output is correct

Subtask #3
37.0 / 37.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	9 ms	11988 KB	Output is correct
2	Correct	8 ms	11988 KB	Output is correct
3	Correct	8 ms	11988 KB	Output is correct
4	Correct	10 ms	12012 KB	Output is correct
5	Correct	7 ms	11988 KB	Output is correct
6	Correct	10 ms	11988 KB	Output is correct
7	Correct	7 ms	11988 KB	Output is correct
8	Correct	7 ms	11988 KB	Output is correct
9	Correct	7 ms	11988 KB	Output is correct
10	Correct	8 ms	11988 KB	Output is correct
11	Correct	8 ms	11988 KB	Output is correct
12	Correct	7 ms	11972 KB	Output is correct
13	Correct	8 ms	11988 KB	Output is correct
14	Correct	7 ms	11988 KB	Output is correct
15	Correct	7 ms	11988 KB	Output is correct
16	Correct	6 ms	12068 KB	Output is correct
17	Correct	8 ms	12060 KB	Output is correct
18	Correct	7 ms	11956 KB	Output is correct
19	Correct	7 ms	11988 KB	Output is correct
20	Correct	6 ms	11988 KB	Output is correct
21	Correct	7 ms	11988 KB	Output is correct
22	Correct	8 ms	12116 KB	Output is correct
23	Correct	8 ms	12076 KB	Output is correct
24	Correct	8 ms	12112 KB	Output is correct
25	Correct	8 ms	12116 KB	Output is correct
26	Correct	7 ms	12116 KB	Output is correct
27	Correct	7 ms	12116 KB	Output is correct
28	Correct	7 ms	12116 KB	Output is correct
29	Correct	7 ms	12116 KB	Output is correct
30	Correct	6 ms	11988 KB	Output is correct
31	Correct	8 ms	12116 KB	Output is correct
32	Correct	7 ms	11988 KB	Output is correct
33	Correct	7 ms	11988 KB	Output is correct
34	Correct	7 ms	11988 KB	Output is correct
35	Correct	7 ms	12060 KB	Output is correct
36	Correct	7 ms	11988 KB	Output is correct
37	Correct	7 ms	12064 KB	Output is correct
38	Correct	9 ms	12068 KB	Output is correct
39	Correct	8 ms	11988 KB	Output is correct
40	Correct	7 ms	11988 KB	Output is correct
41	Correct	7 ms	11988 KB	Output is correct
42	Correct	8 ms	11988 KB	Output is correct
43	Correct	7 ms	12116 KB	Output is correct
44	Correct	7 ms	11988 KB	Output is correct
45	Correct	7 ms	12064 KB	Output is correct
46	Correct	7 ms	11988 KB	Output is correct
47	Correct	9 ms	12064 KB	Output is correct
48	Correct	9 ms	12008 KB	Output is correct
49	Correct	8 ms	12116 KB	Output is correct
50	Correct	7 ms	12024 KB	Output is correct
51	Correct	7 ms	12068 KB	Output is correct
52	Correct	8 ms	12060 KB	Output is correct
53	Correct	9 ms	12072 KB	Output is correct
54	Correct	9 ms	11968 KB	Output is correct
55	Correct	7 ms	12064 KB	Output is correct
56	Correct	7 ms	12072 KB	Output is correct
57	Correct	7 ms	11988 KB	Output is correct
58	Correct	9 ms	12072 KB	Output is correct
59	Correct	383 ms	36032 KB	Output is correct
60	Correct	445 ms	38776 KB	Output is correct
61	Correct	7 ms	11988 KB	Output is correct
62	Correct	9 ms	12072 KB	Output is correct
63	Correct	295 ms	33640 KB	Output is correct
64	Correct	8 ms	12372 KB	Output is correct
65	Correct	15 ms	13864 KB	Output is correct
66	Correct	142 ms	27852 KB	Output is correct
67	Correct	463 ms	46912 KB	Output is correct
68	Correct	477 ms	47744 KB	Output is correct
69	Correct	13 ms	12884 KB	Output is correct
70	Correct	92 ms	21228 KB	Output is correct
71	Correct	252 ms	41916 KB	Output is correct
72	Correct	276 ms	40604 KB	Output is correct
73	Correct	131 ms	19080 KB	Output is correct
74	Correct	458 ms	37668 KB	Output is correct
75	Correct	35 ms	15316 KB	Output is correct
76	Correct	303 ms	41592 KB	Output is correct
77	Correct	275 ms	41576 KB	Output is correct
78	Correct	29 ms	15308 KB	Output is correct
79	Correct	482 ms	45176 KB	Output is correct
80	Correct	9 ms	12204 KB	Output is correct
81	Correct	110 ms	21240 KB	Output is correct
82	Correct	339 ms	39564 KB	Output is correct
83	Correct	439 ms	37588 KB	Output is correct
84	Correct	444 ms	37608 KB	Output is correct
85	Correct	415 ms	37624 KB	Output is correct
86	Correct	422 ms	38692 KB	Output is correct
87	Correct	423 ms	38692 KB	Output is correct

Submission #538944

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