#include <bits/stdc++.h>
//#pragma GCC optimize("Ofast")
#define LL long long
#define se second
#define fi first
using namespace std;
const int N = 5e5 + 7;
const int mod = 1e9 + 7;
const int B = sqrt(N);
int n;
bool used[N];
vector < int > v[N];
vector < int > ans;
void dfs( int x , int p )
{
if( v[x].size() == 1 && !used[x] ){
ans.push_back(x);
}
used[x] = true;
for( auto y : v[x] ){
if( y == p )continue;
dfs(y , x);
}
}
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(NULL);
//freopen( "input.txt" , "r" , stdin );
//freopen( "output.txt" , "w" , stdout );
cin >> n;
for( int i = 1; i < n; i++ ){
int x,y;
cin >> x >> y;
v[x].push_back(y);
v[y].push_back(x);
}
int x = 1;
for( int i = 1; i <= n; i++ ){
if( v[i].size() > 1 ){
x = i;
}
}
dfs(x , x);
int k = (ans.size() + 1) / 2;
cout << ( (int)ans.size() + 1 ) / 2 << "\n";
for( int i = 0; i < ( ans.size() + 1) / 2; i++ ){
cout << ans[i] << " " << ans[ (i + k) % (int)ans.size() ] << "\n";
}
}
Compilation message
net.cpp: In function 'int main()':
net.cpp:54:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for( int i = 0; i < ( ans.size() + 1) / 2; i++ ){
~~^~~~~~~~~~~~~~~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
13 ms |
12152 KB |
Output is correct |
2 |
Correct |
13 ms |
12152 KB |
Output is correct |
3 |
Correct |
12 ms |
12024 KB |
Output is correct |
4 |
Correct |
13 ms |
12152 KB |
Output is correct |
5 |
Correct |
12 ms |
12024 KB |
Output is correct |
6 |
Correct |
12 ms |
12024 KB |
Output is correct |
7 |
Correct |
13 ms |
12152 KB |
Output is correct |
8 |
Correct |
13 ms |
12008 KB |
Output is correct |
9 |
Correct |
12 ms |
12024 KB |
Output is correct |
10 |
Correct |
13 ms |
12024 KB |
Output is correct |
11 |
Correct |
12 ms |
12024 KB |
Output is correct |
12 |
Correct |
13 ms |
12152 KB |
Output is correct |
13 |
Correct |
13 ms |
12024 KB |
Output is correct |
14 |
Correct |
13 ms |
12024 KB |
Output is correct |
15 |
Correct |
13 ms |
12024 KB |
Output is correct |
16 |
Correct |
13 ms |
12024 KB |
Output is correct |
17 |
Correct |
13 ms |
12024 KB |
Output is correct |
18 |
Correct |
13 ms |
12152 KB |
Output is correct |
19 |
Correct |
13 ms |
12152 KB |
Output is correct |
20 |
Correct |
13 ms |
12152 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
13 ms |
12152 KB |
Output is correct |
2 |
Correct |
13 ms |
12152 KB |
Output is correct |
3 |
Correct |
12 ms |
12024 KB |
Output is correct |
4 |
Correct |
13 ms |
12152 KB |
Output is correct |
5 |
Correct |
12 ms |
12024 KB |
Output is correct |
6 |
Correct |
12 ms |
12024 KB |
Output is correct |
7 |
Correct |
13 ms |
12152 KB |
Output is correct |
8 |
Correct |
13 ms |
12008 KB |
Output is correct |
9 |
Correct |
12 ms |
12024 KB |
Output is correct |
10 |
Correct |
13 ms |
12024 KB |
Output is correct |
11 |
Correct |
12 ms |
12024 KB |
Output is correct |
12 |
Correct |
13 ms |
12152 KB |
Output is correct |
13 |
Correct |
13 ms |
12024 KB |
Output is correct |
14 |
Correct |
13 ms |
12024 KB |
Output is correct |
15 |
Correct |
13 ms |
12024 KB |
Output is correct |
16 |
Correct |
13 ms |
12024 KB |
Output is correct |
17 |
Correct |
13 ms |
12024 KB |
Output is correct |
18 |
Correct |
13 ms |
12152 KB |
Output is correct |
19 |
Correct |
13 ms |
12152 KB |
Output is correct |
20 |
Correct |
13 ms |
12152 KB |
Output is correct |
21 |
Correct |
13 ms |
12024 KB |
Output is correct |
22 |
Correct |
14 ms |
12152 KB |
Output is correct |
23 |
Correct |
14 ms |
12152 KB |
Output is correct |
24 |
Correct |
14 ms |
12124 KB |
Output is correct |
25 |
Correct |
16 ms |
12152 KB |
Output is correct |
26 |
Correct |
13 ms |
12124 KB |
Output is correct |
27 |
Correct |
14 ms |
12152 KB |
Output is correct |
28 |
Correct |
14 ms |
12152 KB |
Output is correct |
29 |
Correct |
14 ms |
12152 KB |
Output is correct |
30 |
Correct |
12 ms |
12152 KB |
Output is correct |
31 |
Correct |
13 ms |
12156 KB |
Output is correct |
32 |
Correct |
13 ms |
12024 KB |
Output is correct |
33 |
Correct |
12 ms |
12152 KB |
Output is correct |
34 |
Correct |
12 ms |
12152 KB |
Output is correct |
35 |
Correct |
12 ms |
12152 KB |
Output is correct |
36 |
Correct |
12 ms |
12152 KB |
Output is correct |
37 |
Correct |
12 ms |
12152 KB |
Output is correct |
38 |
Correct |
12 ms |
12152 KB |
Output is correct |
39 |
Correct |
13 ms |
12024 KB |
Output is correct |
40 |
Correct |
13 ms |
12024 KB |
Output is correct |
41 |
Correct |
12 ms |
12152 KB |
Output is correct |
42 |
Correct |
13 ms |
12152 KB |
Output is correct |
43 |
Correct |
13 ms |
12152 KB |
Output is correct |
44 |
Correct |
12 ms |
12024 KB |
Output is correct |
45 |
Correct |
13 ms |
12152 KB |
Output is correct |
46 |
Correct |
13 ms |
12152 KB |
Output is correct |
47 |
Correct |
12 ms |
12152 KB |
Output is correct |
48 |
Correct |
12 ms |
12152 KB |
Output is correct |
49 |
Correct |
13 ms |
12152 KB |
Output is correct |
50 |
Correct |
12 ms |
12028 KB |
Output is correct |
51 |
Correct |
12 ms |
12152 KB |
Output is correct |
52 |
Correct |
13 ms |
12212 KB |
Output is correct |
53 |
Correct |
13 ms |
12152 KB |
Output is correct |
54 |
Correct |
12 ms |
12028 KB |
Output is correct |
55 |
Correct |
13 ms |
12152 KB |
Output is correct |
56 |
Correct |
12 ms |
12152 KB |
Output is correct |
57 |
Correct |
13 ms |
12152 KB |
Output is correct |
58 |
Correct |
14 ms |
12152 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
13 ms |
12152 KB |
Output is correct |
2 |
Correct |
13 ms |
12152 KB |
Output is correct |
3 |
Correct |
12 ms |
12024 KB |
Output is correct |
4 |
Correct |
13 ms |
12152 KB |
Output is correct |
5 |
Correct |
12 ms |
12024 KB |
Output is correct |
6 |
Correct |
12 ms |
12024 KB |
Output is correct |
7 |
Correct |
13 ms |
12152 KB |
Output is correct |
8 |
Correct |
13 ms |
12008 KB |
Output is correct |
9 |
Correct |
12 ms |
12024 KB |
Output is correct |
10 |
Correct |
13 ms |
12024 KB |
Output is correct |
11 |
Correct |
12 ms |
12024 KB |
Output is correct |
12 |
Correct |
13 ms |
12152 KB |
Output is correct |
13 |
Correct |
13 ms |
12024 KB |
Output is correct |
14 |
Correct |
13 ms |
12024 KB |
Output is correct |
15 |
Correct |
13 ms |
12024 KB |
Output is correct |
16 |
Correct |
13 ms |
12024 KB |
Output is correct |
17 |
Correct |
13 ms |
12024 KB |
Output is correct |
18 |
Correct |
13 ms |
12152 KB |
Output is correct |
19 |
Correct |
13 ms |
12152 KB |
Output is correct |
20 |
Correct |
13 ms |
12152 KB |
Output is correct |
21 |
Correct |
13 ms |
12024 KB |
Output is correct |
22 |
Correct |
14 ms |
12152 KB |
Output is correct |
23 |
Correct |
14 ms |
12152 KB |
Output is correct |
24 |
Correct |
14 ms |
12124 KB |
Output is correct |
25 |
Correct |
16 ms |
12152 KB |
Output is correct |
26 |
Correct |
13 ms |
12124 KB |
Output is correct |
27 |
Correct |
14 ms |
12152 KB |
Output is correct |
28 |
Correct |
14 ms |
12152 KB |
Output is correct |
29 |
Correct |
14 ms |
12152 KB |
Output is correct |
30 |
Correct |
12 ms |
12152 KB |
Output is correct |
31 |
Correct |
13 ms |
12156 KB |
Output is correct |
32 |
Correct |
13 ms |
12024 KB |
Output is correct |
33 |
Correct |
12 ms |
12152 KB |
Output is correct |
34 |
Correct |
12 ms |
12152 KB |
Output is correct |
35 |
Correct |
12 ms |
12152 KB |
Output is correct |
36 |
Correct |
12 ms |
12152 KB |
Output is correct |
37 |
Correct |
12 ms |
12152 KB |
Output is correct |
38 |
Correct |
12 ms |
12152 KB |
Output is correct |
39 |
Correct |
13 ms |
12024 KB |
Output is correct |
40 |
Correct |
13 ms |
12024 KB |
Output is correct |
41 |
Correct |
12 ms |
12152 KB |
Output is correct |
42 |
Correct |
13 ms |
12152 KB |
Output is correct |
43 |
Correct |
13 ms |
12152 KB |
Output is correct |
44 |
Correct |
12 ms |
12024 KB |
Output is correct |
45 |
Correct |
13 ms |
12152 KB |
Output is correct |
46 |
Correct |
13 ms |
12152 KB |
Output is correct |
47 |
Correct |
12 ms |
12152 KB |
Output is correct |
48 |
Correct |
12 ms |
12152 KB |
Output is correct |
49 |
Correct |
13 ms |
12152 KB |
Output is correct |
50 |
Correct |
12 ms |
12028 KB |
Output is correct |
51 |
Correct |
12 ms |
12152 KB |
Output is correct |
52 |
Correct |
13 ms |
12212 KB |
Output is correct |
53 |
Correct |
13 ms |
12152 KB |
Output is correct |
54 |
Correct |
12 ms |
12028 KB |
Output is correct |
55 |
Correct |
13 ms |
12152 KB |
Output is correct |
56 |
Correct |
12 ms |
12152 KB |
Output is correct |
57 |
Correct |
13 ms |
12152 KB |
Output is correct |
58 |
Correct |
14 ms |
12152 KB |
Output is correct |
59 |
Correct |
447 ms |
36552 KB |
Output is correct |
60 |
Correct |
519 ms |
39304 KB |
Output is correct |
61 |
Correct |
13 ms |
12024 KB |
Output is correct |
62 |
Correct |
13 ms |
12152 KB |
Output is correct |
63 |
Correct |
378 ms |
34120 KB |
Output is correct |
64 |
Correct |
15 ms |
12408 KB |
Output is correct |
65 |
Correct |
27 ms |
13796 KB |
Output is correct |
66 |
Correct |
181 ms |
25336 KB |
Output is correct |
67 |
Correct |
608 ms |
58196 KB |
Output is correct |
68 |
Correct |
597 ms |
51324 KB |
Output is correct |
69 |
Correct |
20 ms |
12920 KB |
Output is correct |
70 |
Correct |
124 ms |
21464 KB |
Output is correct |
71 |
Correct |
379 ms |
42288 KB |
Output is correct |
72 |
Correct |
404 ms |
41264 KB |
Output is correct |
73 |
Correct |
132 ms |
19316 KB |
Output is correct |
74 |
Correct |
532 ms |
38248 KB |
Output is correct |
75 |
Correct |
44 ms |
15352 KB |
Output is correct |
76 |
Correct |
383 ms |
42208 KB |
Output is correct |
77 |
Correct |
390 ms |
42188 KB |
Output is correct |
78 |
Correct |
47 ms |
15480 KB |
Output is correct |
79 |
Correct |
595 ms |
45624 KB |
Output is correct |
80 |
Correct |
16 ms |
12408 KB |
Output is correct |
81 |
Correct |
189 ms |
21608 KB |
Output is correct |
82 |
Correct |
465 ms |
40168 KB |
Output is correct |
83 |
Correct |
523 ms |
38328 KB |
Output is correct |
84 |
Correct |
533 ms |
38292 KB |
Output is correct |
85 |
Correct |
556 ms |
38524 KB |
Output is correct |
86 |
Correct |
503 ms |
39272 KB |
Output is correct |
87 |
Correct |
518 ms |
39280 KB |
Output is correct |