Submission #748426

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
748426	2023-05-26T09:29:26 Z	mariowong	Network (BOI15_net)	C++14	100 / 100	514 ms	50136 KB

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

int deg[500005]; 
vector <int> edge[500005]; 
bool vis[500005];
vector <int> v;
void dfs(int x){
	vis[x]=true;
	if (deg[x] == 1) v.push_back(x);
	for (int i=0;i<edge[x].size();i++){
		if (!vis[edge[x][i]]) dfs(edge[x][i]);
	}
}
int main(){
	ios::sync_with_stdio(false); 
	int n;
	cin >> n;
	for (int i=1;i<n;i++){
		int u,v;
		cin >> u >> v;
		edge[u].push_back(v);
		edge[v].push_back(u); 
		deg[u]++; deg[v]++;
	}	
	int cnt=0;
	for (int i=1;i<=n;i++){
		if (deg[i] == 1) cnt++;
	}
	cout << (cnt+1)/2 << "\n";
	for (int i=1;i<=n;i++){
		if (deg[i] > 1){
			dfs(i);
			break;	
		}
	}
	if (cnt%2 == 1) v.push_back(v[(int)v.size()-1]);
	for (int i=0;i+(cnt+1)/2<v.size();i++){
		cout << v[i] << " " << v[i+(cnt+1)/2] << "\n";
	}
	return 0;
}

Compilation message

net.cpp: In function 'void dfs(int)':
net.cpp:11:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   11 |  for (int i=0;i<edge[x].size();i++){
      |               ~^~~~~~~~~~~~~~~
net.cpp: In function 'int main()':
net.cpp:38:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   38 |  for (int i=0;i+(cnt+1)/2<v.size();i++){
      |               ~~~~~~~~~~~^~~~~~~~~

Subtask #1
18.0 / 18.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	7 ms	12064 KB	Output is correct
2	Correct	8 ms	11972 KB	Output is correct
3	Correct	6 ms	11988 KB	Output is correct
4	Correct	8 ms	11996 KB	Output is correct
5	Correct	7 ms	11988 KB	Output is correct
6	Correct	9 ms	11988 KB	Output is correct
7	Correct	7 ms	12036 KB	Output is correct
8	Correct	7 ms	11988 KB	Output is correct
9	Correct	8 ms	11988 KB	Output is correct
10	Correct	7 ms	11988 KB	Output is correct
11	Correct	7 ms	12044 KB	Output is correct
12	Correct	7 ms	12076 KB	Output is correct
13	Correct	7 ms	11988 KB	Output is correct
14	Correct	8 ms	11988 KB	Output is correct
15	Correct	8 ms	11988 KB	Output is correct
16	Correct	7 ms	11988 KB	Output is correct
17	Correct	6 ms	11988 KB	Output is correct
18	Correct	6 ms	11988 KB	Output is correct
19	Correct	9 ms	11988 KB	Output is correct
20	Correct	7 ms	12076 KB	Output is correct

Subtask #2
45.0 / 45.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	7 ms	12064 KB	Output is correct
2	Correct	8 ms	11972 KB	Output is correct
3	Correct	6 ms	11988 KB	Output is correct
4	Correct	8 ms	11996 KB	Output is correct
5	Correct	7 ms	11988 KB	Output is correct
6	Correct	9 ms	11988 KB	Output is correct
7	Correct	7 ms	12036 KB	Output is correct
8	Correct	7 ms	11988 KB	Output is correct
9	Correct	8 ms	11988 KB	Output is correct
10	Correct	7 ms	11988 KB	Output is correct
11	Correct	7 ms	12044 KB	Output is correct
12	Correct	7 ms	12076 KB	Output is correct
13	Correct	7 ms	11988 KB	Output is correct
14	Correct	8 ms	11988 KB	Output is correct
15	Correct	8 ms	11988 KB	Output is correct
16	Correct	7 ms	11988 KB	Output is correct
17	Correct	6 ms	11988 KB	Output is correct
18	Correct	6 ms	11988 KB	Output is correct
19	Correct	9 ms	11988 KB	Output is correct
20	Correct	7 ms	12076 KB	Output is correct
21	Correct	7 ms	12004 KB	Output is correct
22	Correct	8 ms	12116 KB	Output is correct
23	Correct	8 ms	12116 KB	Output is correct
24	Correct	7 ms	12116 KB	Output is correct
25	Correct	7 ms	12132 KB	Output is correct
26	Correct	7 ms	12116 KB	Output is correct
27	Correct	7 ms	12092 KB	Output is correct
28	Correct	8 ms	12092 KB	Output is correct
29	Correct	8 ms	12116 KB	Output is correct
30	Correct	6 ms	11988 KB	Output is correct
31	Correct	8 ms	12088 KB	Output is correct
32	Correct	7 ms	12068 KB	Output is correct
33	Correct	7 ms	12072 KB	Output is correct
34	Correct	8 ms	12072 KB	Output is correct
35	Correct	7 ms	12116 KB	Output is correct
36	Correct	7 ms	11988 KB	Output is correct
37	Correct	7 ms	12116 KB	Output is correct
38	Correct	7 ms	12084 KB	Output is correct
39	Correct	10 ms	11964 KB	Output is correct
40	Correct	6 ms	11988 KB	Output is correct
41	Correct	7 ms	11992 KB	Output is correct
42	Correct	7 ms	11988 KB	Output is correct
43	Correct	7 ms	12116 KB	Output is correct
44	Correct	6 ms	11988 KB	Output is correct
45	Correct	7 ms	12072 KB	Output is correct
46	Correct	7 ms	12080 KB	Output is correct
47	Correct	7 ms	11988 KB	Output is correct
48	Correct	8 ms	11988 KB	Output is correct
49	Correct	7 ms	12116 KB	Output is correct
50	Correct	6 ms	11988 KB	Output is correct
51	Correct	7 ms	11988 KB	Output is correct
52	Correct	9 ms	12080 KB	Output is correct
53	Correct	7 ms	12064 KB	Output is correct
54	Correct	6 ms	12076 KB	Output is correct
55	Correct	7 ms	12076 KB	Output is correct
56	Correct	7 ms	12072 KB	Output is correct
57	Correct	8 ms	11988 KB	Output is correct
58	Correct	8 ms	12092 KB	Output is correct

Subtask #3
37.0 / 37.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	7 ms	12064 KB	Output is correct
2	Correct	8 ms	11972 KB	Output is correct
3	Correct	6 ms	11988 KB	Output is correct
4	Correct	8 ms	11996 KB	Output is correct
5	Correct	7 ms	11988 KB	Output is correct
6	Correct	9 ms	11988 KB	Output is correct
7	Correct	7 ms	12036 KB	Output is correct
8	Correct	7 ms	11988 KB	Output is correct
9	Correct	8 ms	11988 KB	Output is correct
10	Correct	7 ms	11988 KB	Output is correct
11	Correct	7 ms	12044 KB	Output is correct
12	Correct	7 ms	12076 KB	Output is correct
13	Correct	7 ms	11988 KB	Output is correct
14	Correct	8 ms	11988 KB	Output is correct
15	Correct	8 ms	11988 KB	Output is correct
16	Correct	7 ms	11988 KB	Output is correct
17	Correct	6 ms	11988 KB	Output is correct
18	Correct	6 ms	11988 KB	Output is correct
19	Correct	9 ms	11988 KB	Output is correct
20	Correct	7 ms	12076 KB	Output is correct
21	Correct	7 ms	12004 KB	Output is correct
22	Correct	8 ms	12116 KB	Output is correct
23	Correct	8 ms	12116 KB	Output is correct
24	Correct	7 ms	12116 KB	Output is correct
25	Correct	7 ms	12132 KB	Output is correct
26	Correct	7 ms	12116 KB	Output is correct
27	Correct	7 ms	12092 KB	Output is correct
28	Correct	8 ms	12092 KB	Output is correct
29	Correct	8 ms	12116 KB	Output is correct
30	Correct	6 ms	11988 KB	Output is correct
31	Correct	8 ms	12088 KB	Output is correct
32	Correct	7 ms	12068 KB	Output is correct
33	Correct	7 ms	12072 KB	Output is correct
34	Correct	8 ms	12072 KB	Output is correct
35	Correct	7 ms	12116 KB	Output is correct
36	Correct	7 ms	11988 KB	Output is correct
37	Correct	7 ms	12116 KB	Output is correct
38	Correct	7 ms	12084 KB	Output is correct
39	Correct	10 ms	11964 KB	Output is correct
40	Correct	6 ms	11988 KB	Output is correct
41	Correct	7 ms	11992 KB	Output is correct
42	Correct	7 ms	11988 KB	Output is correct
43	Correct	7 ms	12116 KB	Output is correct
44	Correct	6 ms	11988 KB	Output is correct
45	Correct	7 ms	12072 KB	Output is correct
46	Correct	7 ms	12080 KB	Output is correct
47	Correct	7 ms	11988 KB	Output is correct
48	Correct	8 ms	11988 KB	Output is correct
49	Correct	7 ms	12116 KB	Output is correct
50	Correct	6 ms	11988 KB	Output is correct
51	Correct	7 ms	11988 KB	Output is correct
52	Correct	9 ms	12080 KB	Output is correct
53	Correct	7 ms	12064 KB	Output is correct
54	Correct	6 ms	12076 KB	Output is correct
55	Correct	7 ms	12076 KB	Output is correct
56	Correct	7 ms	12072 KB	Output is correct
57	Correct	8 ms	11988 KB	Output is correct
58	Correct	8 ms	12092 KB	Output is correct
59	Correct	392 ms	38228 KB	Output is correct
60	Correct	412 ms	41216 KB	Output is correct
61	Correct	7 ms	12060 KB	Output is correct
62	Correct	7 ms	12076 KB	Output is correct
63	Correct	304 ms	35520 KB	Output is correct
64	Correct	8 ms	12500 KB	Output is correct
65	Correct	17 ms	14044 KB	Output is correct
66	Correct	140 ms	28692 KB	Output is correct
67	Correct	502 ms	49268 KB	Output is correct
68	Correct	514 ms	50136 KB	Output is correct
69	Correct	12 ms	13012 KB	Output is correct
70	Correct	83 ms	22036 KB	Output is correct
71	Correct	309 ms	44320 KB	Output is correct
72	Correct	318 ms	43124 KB	Output is correct
73	Correct	86 ms	19784 KB	Output is correct
74	Correct	483 ms	40104 KB	Output is correct
75	Correct	26 ms	15572 KB	Output is correct
76	Correct	288 ms	44000 KB	Output is correct
77	Correct	282 ms	44064 KB	Output is correct
78	Correct	29 ms	15832 KB	Output is correct
79	Correct	513 ms	47504 KB	Output is correct
80	Correct	8 ms	12244 KB	Output is correct
81	Correct	95 ms	22112 KB	Output is correct
82	Correct	370 ms	41900 KB	Output is correct
83	Correct	446 ms	40140 KB	Output is correct
84	Correct	458 ms	40048 KB	Output is correct
85	Correct	453 ms	40116 KB	Output is correct
86	Correct	462 ms	41224 KB	Output is correct
87	Correct	441 ms	41340 KB	Output is correct

Submission #748426

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