#include <bits/stdc++.h>
#define HID ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define int long long
#define all(v) v.begin(),v.end()
const int N = 500010 , INF = 1e15 , MOD=1000000006;
using namespace std;
int n ;
vector<int>edges[N];
vector<int>leaves;
void dfs(int node , int par)
{
if(edges[node].size()==1) leaves.push_back(node);
for(auto x : edges[node])
if(x!=par)
dfs(x,node);
}
int32_t main() {
HID
cin>>n;
for(int i = 0 ; i < n-1 ; i++)
{
int u , v;
cin >> u >> v;
edges[u].push_back(v);
edges[v].push_back(u);
}
dfs(1,-1);
cout<<(leaves.size()+1)/2<<endl;
if(leaves.size()%2==0)
{
for(int i = 0 ; i < leaves.size()/2 ; i++)
cout<<leaves[i]<<" "<<leaves[leaves.size()/2+i]<<endl;
}
else
{
for(int i = 0 ; i < leaves.size()/2 ; i++)
{
if(i==leaves.size()-1) break;
cout<<leaves[i]<<" "<<leaves[leaves.size()/2+i]<<endl;
}
cout<<leaves.back()<<" ";
for(int i = 1 ; i <= n ; i++)
{
if(i!=leaves.back()&&i!=edges[leaves.back()][0])
{
cout<<i<<endl;
break;
}
}
}
}
Compilation message
net.cpp: In function 'int32_t main()':
net.cpp:31:23: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
31 | for(int i = 0 ; i < leaves.size()/2 ; i++)
| ~~^~~~~~~~~~~~~~~~~
net.cpp:36:23: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
36 | for(int i = 0 ; i < leaves.size()/2 ; i++)
| ~~^~~~~~~~~~~~~~~~~
net.cpp:38:11: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
38 | if(i==leaves.size()-1) break;
| ~^~~~~~~~~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
9 ms |
11980 KB |
Output is correct |
2 |
Correct |
6 ms |
11980 KB |
Output is correct |
3 |
Correct |
6 ms |
11980 KB |
Output is correct |
4 |
Correct |
6 ms |
11980 KB |
Output is correct |
5 |
Correct |
6 ms |
11976 KB |
Output is correct |
6 |
Correct |
8 ms |
11980 KB |
Output is correct |
7 |
Correct |
6 ms |
12044 KB |
Output is correct |
8 |
Correct |
6 ms |
11980 KB |
Output is correct |
9 |
Correct |
6 ms |
11952 KB |
Output is correct |
10 |
Correct |
7 ms |
12036 KB |
Output is correct |
11 |
Correct |
6 ms |
11960 KB |
Output is correct |
12 |
Correct |
6 ms |
11980 KB |
Output is correct |
13 |
Correct |
9 ms |
11980 KB |
Output is correct |
14 |
Correct |
7 ms |
11980 KB |
Output is correct |
15 |
Correct |
6 ms |
11980 KB |
Output is correct |
16 |
Correct |
6 ms |
11980 KB |
Output is correct |
17 |
Correct |
6 ms |
11980 KB |
Output is correct |
18 |
Correct |
6 ms |
11980 KB |
Output is correct |
19 |
Correct |
7 ms |
11980 KB |
Output is correct |
20 |
Correct |
6 ms |
11980 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
9 ms |
11980 KB |
Output is correct |
2 |
Correct |
6 ms |
11980 KB |
Output is correct |
3 |
Correct |
6 ms |
11980 KB |
Output is correct |
4 |
Correct |
6 ms |
11980 KB |
Output is correct |
5 |
Correct |
6 ms |
11976 KB |
Output is correct |
6 |
Correct |
8 ms |
11980 KB |
Output is correct |
7 |
Correct |
6 ms |
12044 KB |
Output is correct |
8 |
Correct |
6 ms |
11980 KB |
Output is correct |
9 |
Correct |
6 ms |
11952 KB |
Output is correct |
10 |
Correct |
7 ms |
12036 KB |
Output is correct |
11 |
Correct |
6 ms |
11960 KB |
Output is correct |
12 |
Correct |
6 ms |
11980 KB |
Output is correct |
13 |
Correct |
9 ms |
11980 KB |
Output is correct |
14 |
Correct |
7 ms |
11980 KB |
Output is correct |
15 |
Correct |
6 ms |
11980 KB |
Output is correct |
16 |
Correct |
6 ms |
11980 KB |
Output is correct |
17 |
Correct |
6 ms |
11980 KB |
Output is correct |
18 |
Correct |
6 ms |
11980 KB |
Output is correct |
19 |
Correct |
7 ms |
11980 KB |
Output is correct |
20 |
Correct |
6 ms |
11980 KB |
Output is correct |
21 |
Correct |
6 ms |
11980 KB |
Output is correct |
22 |
Correct |
8 ms |
12164 KB |
Output is correct |
23 |
Correct |
8 ms |
12108 KB |
Output is correct |
24 |
Correct |
9 ms |
12108 KB |
Output is correct |
25 |
Correct |
8 ms |
12108 KB |
Output is correct |
26 |
Correct |
8 ms |
12108 KB |
Output is correct |
27 |
Correct |
8 ms |
12108 KB |
Output is correct |
28 |
Correct |
9 ms |
12152 KB |
Output is correct |
29 |
Correct |
7 ms |
12108 KB |
Output is correct |
30 |
Correct |
6 ms |
11980 KB |
Output is correct |
31 |
Correct |
8 ms |
12108 KB |
Output is correct |
32 |
Correct |
9 ms |
11980 KB |
Output is correct |
33 |
Correct |
7 ms |
11980 KB |
Output is correct |
34 |
Correct |
7 ms |
11980 KB |
Output is correct |
35 |
Correct |
7 ms |
11980 KB |
Output is correct |
36 |
Correct |
6 ms |
11980 KB |
Output is correct |
37 |
Correct |
7 ms |
11980 KB |
Output is correct |
38 |
Correct |
6 ms |
12108 KB |
Output is correct |
39 |
Correct |
6 ms |
11980 KB |
Output is correct |
40 |
Correct |
7 ms |
11980 KB |
Output is correct |
41 |
Correct |
6 ms |
11980 KB |
Output is correct |
42 |
Correct |
7 ms |
11980 KB |
Output is correct |
43 |
Correct |
7 ms |
12108 KB |
Output is correct |
44 |
Correct |
6 ms |
11960 KB |
Output is correct |
45 |
Correct |
6 ms |
11980 KB |
Output is correct |
46 |
Correct |
7 ms |
11980 KB |
Output is correct |
47 |
Correct |
7 ms |
11980 KB |
Output is correct |
48 |
Correct |
8 ms |
11980 KB |
Output is correct |
49 |
Correct |
9 ms |
12108 KB |
Output is correct |
50 |
Correct |
7 ms |
11980 KB |
Output is correct |
51 |
Correct |
7 ms |
11980 KB |
Output is correct |
52 |
Correct |
7 ms |
11980 KB |
Output is correct |
53 |
Correct |
8 ms |
12112 KB |
Output is correct |
54 |
Correct |
7 ms |
11944 KB |
Output is correct |
55 |
Correct |
7 ms |
11980 KB |
Output is correct |
56 |
Correct |
7 ms |
11980 KB |
Output is correct |
57 |
Correct |
8 ms |
11980 KB |
Output is correct |
58 |
Correct |
11 ms |
12108 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
9 ms |
11980 KB |
Output is correct |
2 |
Correct |
6 ms |
11980 KB |
Output is correct |
3 |
Correct |
6 ms |
11980 KB |
Output is correct |
4 |
Correct |
6 ms |
11980 KB |
Output is correct |
5 |
Correct |
6 ms |
11976 KB |
Output is correct |
6 |
Correct |
8 ms |
11980 KB |
Output is correct |
7 |
Correct |
6 ms |
12044 KB |
Output is correct |
8 |
Correct |
6 ms |
11980 KB |
Output is correct |
9 |
Correct |
6 ms |
11952 KB |
Output is correct |
10 |
Correct |
7 ms |
12036 KB |
Output is correct |
11 |
Correct |
6 ms |
11960 KB |
Output is correct |
12 |
Correct |
6 ms |
11980 KB |
Output is correct |
13 |
Correct |
9 ms |
11980 KB |
Output is correct |
14 |
Correct |
7 ms |
11980 KB |
Output is correct |
15 |
Correct |
6 ms |
11980 KB |
Output is correct |
16 |
Correct |
6 ms |
11980 KB |
Output is correct |
17 |
Correct |
6 ms |
11980 KB |
Output is correct |
18 |
Correct |
6 ms |
11980 KB |
Output is correct |
19 |
Correct |
7 ms |
11980 KB |
Output is correct |
20 |
Correct |
6 ms |
11980 KB |
Output is correct |
21 |
Correct |
6 ms |
11980 KB |
Output is correct |
22 |
Correct |
8 ms |
12164 KB |
Output is correct |
23 |
Correct |
8 ms |
12108 KB |
Output is correct |
24 |
Correct |
9 ms |
12108 KB |
Output is correct |
25 |
Correct |
8 ms |
12108 KB |
Output is correct |
26 |
Correct |
8 ms |
12108 KB |
Output is correct |
27 |
Correct |
8 ms |
12108 KB |
Output is correct |
28 |
Correct |
9 ms |
12152 KB |
Output is correct |
29 |
Correct |
7 ms |
12108 KB |
Output is correct |
30 |
Correct |
6 ms |
11980 KB |
Output is correct |
31 |
Correct |
8 ms |
12108 KB |
Output is correct |
32 |
Correct |
9 ms |
11980 KB |
Output is correct |
33 |
Correct |
7 ms |
11980 KB |
Output is correct |
34 |
Correct |
7 ms |
11980 KB |
Output is correct |
35 |
Correct |
7 ms |
11980 KB |
Output is correct |
36 |
Correct |
6 ms |
11980 KB |
Output is correct |
37 |
Correct |
7 ms |
11980 KB |
Output is correct |
38 |
Correct |
6 ms |
12108 KB |
Output is correct |
39 |
Correct |
6 ms |
11980 KB |
Output is correct |
40 |
Correct |
7 ms |
11980 KB |
Output is correct |
41 |
Correct |
6 ms |
11980 KB |
Output is correct |
42 |
Correct |
7 ms |
11980 KB |
Output is correct |
43 |
Correct |
7 ms |
12108 KB |
Output is correct |
44 |
Correct |
6 ms |
11960 KB |
Output is correct |
45 |
Correct |
6 ms |
11980 KB |
Output is correct |
46 |
Correct |
7 ms |
11980 KB |
Output is correct |
47 |
Correct |
7 ms |
11980 KB |
Output is correct |
48 |
Correct |
8 ms |
11980 KB |
Output is correct |
49 |
Correct |
9 ms |
12108 KB |
Output is correct |
50 |
Correct |
7 ms |
11980 KB |
Output is correct |
51 |
Correct |
7 ms |
11980 KB |
Output is correct |
52 |
Correct |
7 ms |
11980 KB |
Output is correct |
53 |
Correct |
8 ms |
12112 KB |
Output is correct |
54 |
Correct |
7 ms |
11944 KB |
Output is correct |
55 |
Correct |
7 ms |
11980 KB |
Output is correct |
56 |
Correct |
7 ms |
11980 KB |
Output is correct |
57 |
Correct |
8 ms |
11980 KB |
Output is correct |
58 |
Correct |
11 ms |
12108 KB |
Output is correct |
59 |
Correct |
548 ms |
34612 KB |
Output is correct |
60 |
Correct |
603 ms |
36736 KB |
Output is correct |
61 |
Correct |
8 ms |
12056 KB |
Output is correct |
62 |
Correct |
6 ms |
11980 KB |
Output is correct |
63 |
Correct |
480 ms |
31328 KB |
Output is correct |
64 |
Correct |
8 ms |
12364 KB |
Output is correct |
65 |
Correct |
15 ms |
13676 KB |
Output is correct |
66 |
Correct |
145 ms |
25560 KB |
Output is correct |
67 |
Correct |
424 ms |
40240 KB |
Output is correct |
68 |
Correct |
531 ms |
41888 KB |
Output is correct |
69 |
Correct |
20 ms |
12876 KB |
Output is correct |
70 |
Correct |
187 ms |
21204 KB |
Output is correct |
71 |
Correct |
618 ms |
38956 KB |
Output is correct |
72 |
Correct |
602 ms |
37964 KB |
Output is correct |
73 |
Correct |
185 ms |
18408 KB |
Output is correct |
74 |
Correct |
553 ms |
34508 KB |
Output is correct |
75 |
Correct |
59 ms |
15036 KB |
Output is correct |
76 |
Correct |
610 ms |
38528 KB |
Output is correct |
77 |
Correct |
614 ms |
39084 KB |
Output is correct |
78 |
Correct |
37 ms |
15044 KB |
Output is correct |
79 |
Incorrect |
440 ms |
38504 KB |
Breaking single line is causing network to disconnect. |
80 |
Halted |
0 ms |
0 KB |
- |