#include <bits/stdc++.h>
using namespace std;
#define int long long
#define sp << ' ' <<
#define nl << '\n'
vector<vector<int>> g;
vector<int> leaves;
void dfs(int u, int p){
if(g[u].size() == 1) leaves.push_back(u);
for(int v : g[u]) if(v != p) dfs(v, u);
}
signed main(){
cin.tie(0)->sync_with_stdio(0);
int n, a, b; cin >> n;
g.resize(n);
for(int i=1; i<n; ++i){
cin >> a >> b; --a, --b;
g[a].push_back(b);
g[b].push_back(a);
}
dfs(0, 0);
int c = leaves.size();
cout << (c+1)/2 nl;
for(int i=0; i<c/2; ++i) cout << leaves[i]+1 sp leaves[i+c/2]+1 nl;
if(c & 1) cout << leaves[0]+1 sp leaves[c-1]+1 nl;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
204 KB |
Output is correct |
2 |
Correct |
1 ms |
204 KB |
Output is correct |
3 |
Correct |
1 ms |
204 KB |
Output is correct |
4 |
Correct |
1 ms |
204 KB |
Output is correct |
5 |
Correct |
1 ms |
204 KB |
Output is correct |
6 |
Correct |
1 ms |
204 KB |
Output is correct |
7 |
Correct |
1 ms |
204 KB |
Output is correct |
8 |
Correct |
1 ms |
204 KB |
Output is correct |
9 |
Correct |
1 ms |
204 KB |
Output is correct |
10 |
Correct |
1 ms |
204 KB |
Output is correct |
11 |
Correct |
1 ms |
204 KB |
Output is correct |
12 |
Correct |
1 ms |
204 KB |
Output is correct |
13 |
Correct |
1 ms |
316 KB |
Output is correct |
14 |
Correct |
1 ms |
204 KB |
Output is correct |
15 |
Correct |
1 ms |
312 KB |
Output is correct |
16 |
Correct |
1 ms |
204 KB |
Output is correct |
17 |
Correct |
1 ms |
204 KB |
Output is correct |
18 |
Correct |
1 ms |
204 KB |
Output is correct |
19 |
Correct |
1 ms |
204 KB |
Output is correct |
20 |
Correct |
1 ms |
204 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
204 KB |
Output is correct |
2 |
Correct |
1 ms |
204 KB |
Output is correct |
3 |
Correct |
1 ms |
204 KB |
Output is correct |
4 |
Correct |
1 ms |
204 KB |
Output is correct |
5 |
Correct |
1 ms |
204 KB |
Output is correct |
6 |
Correct |
1 ms |
204 KB |
Output is correct |
7 |
Correct |
1 ms |
204 KB |
Output is correct |
8 |
Correct |
1 ms |
204 KB |
Output is correct |
9 |
Correct |
1 ms |
204 KB |
Output is correct |
10 |
Correct |
1 ms |
204 KB |
Output is correct |
11 |
Correct |
1 ms |
204 KB |
Output is correct |
12 |
Correct |
1 ms |
204 KB |
Output is correct |
13 |
Correct |
1 ms |
316 KB |
Output is correct |
14 |
Correct |
1 ms |
204 KB |
Output is correct |
15 |
Correct |
1 ms |
312 KB |
Output is correct |
16 |
Correct |
1 ms |
204 KB |
Output is correct |
17 |
Correct |
1 ms |
204 KB |
Output is correct |
18 |
Correct |
1 ms |
204 KB |
Output is correct |
19 |
Correct |
1 ms |
204 KB |
Output is correct |
20 |
Correct |
1 ms |
204 KB |
Output is correct |
21 |
Correct |
1 ms |
208 KB |
Output is correct |
22 |
Correct |
1 ms |
460 KB |
Output is correct |
23 |
Correct |
2 ms |
452 KB |
Output is correct |
24 |
Correct |
1 ms |
460 KB |
Output is correct |
25 |
Correct |
1 ms |
460 KB |
Output is correct |
26 |
Correct |
1 ms |
332 KB |
Output is correct |
27 |
Correct |
1 ms |
460 KB |
Output is correct |
28 |
Correct |
1 ms |
460 KB |
Output is correct |
29 |
Correct |
1 ms |
332 KB |
Output is correct |
30 |
Correct |
1 ms |
204 KB |
Output is correct |
31 |
Correct |
1 ms |
460 KB |
Output is correct |
32 |
Correct |
1 ms |
204 KB |
Output is correct |
33 |
Correct |
1 ms |
204 KB |
Output is correct |
34 |
Correct |
1 ms |
404 KB |
Output is correct |
35 |
Correct |
1 ms |
204 KB |
Output is correct |
36 |
Correct |
1 ms |
204 KB |
Output is correct |
37 |
Correct |
1 ms |
332 KB |
Output is correct |
38 |
Correct |
1 ms |
336 KB |
Output is correct |
39 |
Correct |
1 ms |
316 KB |
Output is correct |
40 |
Correct |
1 ms |
204 KB |
Output is correct |
41 |
Correct |
1 ms |
204 KB |
Output is correct |
42 |
Correct |
1 ms |
332 KB |
Output is correct |
43 |
Correct |
1 ms |
332 KB |
Output is correct |
44 |
Correct |
1 ms |
204 KB |
Output is correct |
45 |
Correct |
1 ms |
332 KB |
Output is correct |
46 |
Correct |
1 ms |
332 KB |
Output is correct |
47 |
Correct |
1 ms |
204 KB |
Output is correct |
48 |
Correct |
1 ms |
332 KB |
Output is correct |
49 |
Correct |
1 ms |
332 KB |
Output is correct |
50 |
Correct |
1 ms |
204 KB |
Output is correct |
51 |
Correct |
1 ms |
204 KB |
Output is correct |
52 |
Correct |
1 ms |
332 KB |
Output is correct |
53 |
Correct |
1 ms |
332 KB |
Output is correct |
54 |
Correct |
2 ms |
204 KB |
Output is correct |
55 |
Correct |
1 ms |
332 KB |
Output is correct |
56 |
Correct |
1 ms |
204 KB |
Output is correct |
57 |
Correct |
1 ms |
332 KB |
Output is correct |
58 |
Correct |
1 ms |
460 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
204 KB |
Output is correct |
2 |
Correct |
1 ms |
204 KB |
Output is correct |
3 |
Correct |
1 ms |
204 KB |
Output is correct |
4 |
Correct |
1 ms |
204 KB |
Output is correct |
5 |
Correct |
1 ms |
204 KB |
Output is correct |
6 |
Correct |
1 ms |
204 KB |
Output is correct |
7 |
Correct |
1 ms |
204 KB |
Output is correct |
8 |
Correct |
1 ms |
204 KB |
Output is correct |
9 |
Correct |
1 ms |
204 KB |
Output is correct |
10 |
Correct |
1 ms |
204 KB |
Output is correct |
11 |
Correct |
1 ms |
204 KB |
Output is correct |
12 |
Correct |
1 ms |
204 KB |
Output is correct |
13 |
Correct |
1 ms |
316 KB |
Output is correct |
14 |
Correct |
1 ms |
204 KB |
Output is correct |
15 |
Correct |
1 ms |
312 KB |
Output is correct |
16 |
Correct |
1 ms |
204 KB |
Output is correct |
17 |
Correct |
1 ms |
204 KB |
Output is correct |
18 |
Correct |
1 ms |
204 KB |
Output is correct |
19 |
Correct |
1 ms |
204 KB |
Output is correct |
20 |
Correct |
1 ms |
204 KB |
Output is correct |
21 |
Correct |
1 ms |
208 KB |
Output is correct |
22 |
Correct |
1 ms |
460 KB |
Output is correct |
23 |
Correct |
2 ms |
452 KB |
Output is correct |
24 |
Correct |
1 ms |
460 KB |
Output is correct |
25 |
Correct |
1 ms |
460 KB |
Output is correct |
26 |
Correct |
1 ms |
332 KB |
Output is correct |
27 |
Correct |
1 ms |
460 KB |
Output is correct |
28 |
Correct |
1 ms |
460 KB |
Output is correct |
29 |
Correct |
1 ms |
332 KB |
Output is correct |
30 |
Correct |
1 ms |
204 KB |
Output is correct |
31 |
Correct |
1 ms |
460 KB |
Output is correct |
32 |
Correct |
1 ms |
204 KB |
Output is correct |
33 |
Correct |
1 ms |
204 KB |
Output is correct |
34 |
Correct |
1 ms |
404 KB |
Output is correct |
35 |
Correct |
1 ms |
204 KB |
Output is correct |
36 |
Correct |
1 ms |
204 KB |
Output is correct |
37 |
Correct |
1 ms |
332 KB |
Output is correct |
38 |
Correct |
1 ms |
336 KB |
Output is correct |
39 |
Correct |
1 ms |
316 KB |
Output is correct |
40 |
Correct |
1 ms |
204 KB |
Output is correct |
41 |
Correct |
1 ms |
204 KB |
Output is correct |
42 |
Correct |
1 ms |
332 KB |
Output is correct |
43 |
Correct |
1 ms |
332 KB |
Output is correct |
44 |
Correct |
1 ms |
204 KB |
Output is correct |
45 |
Correct |
1 ms |
332 KB |
Output is correct |
46 |
Correct |
1 ms |
332 KB |
Output is correct |
47 |
Correct |
1 ms |
204 KB |
Output is correct |
48 |
Correct |
1 ms |
332 KB |
Output is correct |
49 |
Correct |
1 ms |
332 KB |
Output is correct |
50 |
Correct |
1 ms |
204 KB |
Output is correct |
51 |
Correct |
1 ms |
204 KB |
Output is correct |
52 |
Correct |
1 ms |
332 KB |
Output is correct |
53 |
Correct |
1 ms |
332 KB |
Output is correct |
54 |
Correct |
2 ms |
204 KB |
Output is correct |
55 |
Correct |
1 ms |
332 KB |
Output is correct |
56 |
Correct |
1 ms |
204 KB |
Output is correct |
57 |
Correct |
1 ms |
332 KB |
Output is correct |
58 |
Correct |
1 ms |
460 KB |
Output is correct |
59 |
Correct |
370 ms |
34740 KB |
Output is correct |
60 |
Correct |
468 ms |
38060 KB |
Output is correct |
61 |
Correct |
1 ms |
204 KB |
Output is correct |
62 |
Correct |
1 ms |
204 KB |
Output is correct |
63 |
Correct |
322 ms |
30504 KB |
Output is correct |
64 |
Correct |
2 ms |
844 KB |
Output is correct |
65 |
Correct |
11 ms |
2764 KB |
Output is correct |
66 |
Correct |
129 ms |
19456 KB |
Output is correct |
67 |
Correct |
510 ms |
41676 KB |
Output is correct |
68 |
Correct |
516 ms |
43280 KB |
Output is correct |
69 |
Correct |
6 ms |
1740 KB |
Output is correct |
70 |
Correct |
87 ms |
14568 KB |
Output is correct |
71 |
Correct |
321 ms |
40420 KB |
Output is correct |
72 |
Correct |
353 ms |
39356 KB |
Output is correct |
73 |
Correct |
86 ms |
11196 KB |
Output is correct |
74 |
Correct |
475 ms |
35904 KB |
Output is correct |
75 |
Correct |
25 ms |
5180 KB |
Output is correct |
76 |
Correct |
320 ms |
39920 KB |
Output is correct |
77 |
Correct |
314 ms |
40344 KB |
Output is correct |
78 |
Correct |
25 ms |
5188 KB |
Output is correct |
79 |
Correct |
499 ms |
39920 KB |
Output is correct |
80 |
Correct |
2 ms |
588 KB |
Output is correct |
81 |
Correct |
102 ms |
14024 KB |
Output is correct |
82 |
Correct |
393 ms |
38196 KB |
Output is correct |
83 |
Correct |
455 ms |
36096 KB |
Output is correct |
84 |
Correct |
451 ms |
35820 KB |
Output is correct |
85 |
Correct |
513 ms |
35800 KB |
Output is correct |
86 |
Correct |
457 ms |
38056 KB |
Output is correct |
87 |
Correct |
470 ms |
38132 KB |
Output is correct |