#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
typedef pair<int, int> ii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<vi> vvi;
int timer, n;
vvi adj;
vii leaves;
void dfs(int u, int p) {
//cerr << "// dfs(" << u << ", " << p << ")\n";
timer++;
if (adj[u].size() == 1) leaves.push_back({timer, u});
for (int v : adj[u]) if (v != p) dfs(v, u);
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cin >> n;
adj.assign(n + 20, vi());
for (int i = 0; i < n - 1; i++) {
int a, b;
cin >> a >> b;
a--; b--;
adj[a].push_back(b);
adj[b].push_back(a);
}
dfs(0, -1);
sort(leaves.begin(), leaves.end());
//cerr << "// leaves :";
//for (ii leaf : leaves) cerr << " {" << leaf.fi << ", " << leaf.se << '}';
//cerr << '\n';
int leafCount = leaves.size();
int edgeCount = (leaves.size() + 1) / 2;
cout << edgeCount << '\n';
for (int i = 0; i < edgeCount; i++) {
int j = edgeCount + i;
if (i == j) j = 0;
cout << leaves[i].se + 1 << ' ' << leaves[j].se + 1 << '\n';
}
}
Compilation message
net.cpp: In function 'int main()':
net.cpp:45:7: warning: unused variable 'leafCount' [-Wunused-variable]
45 | int leafCount = leaves.size();
| ^~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
204 KB |
Output is correct |
2 |
Correct |
0 ms |
204 KB |
Output is correct |
3 |
Correct |
0 ms |
204 KB |
Output is correct |
4 |
Correct |
0 ms |
204 KB |
Output is correct |
5 |
Correct |
0 ms |
204 KB |
Output is correct |
6 |
Correct |
0 ms |
204 KB |
Output is correct |
7 |
Correct |
0 ms |
204 KB |
Output is correct |
8 |
Correct |
0 ms |
204 KB |
Output is correct |
9 |
Correct |
0 ms |
204 KB |
Output is correct |
10 |
Correct |
0 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 |
0 ms |
204 KB |
Output is correct |
14 |
Correct |
1 ms |
204 KB |
Output is correct |
15 |
Correct |
0 ms |
204 KB |
Output is correct |
16 |
Correct |
0 ms |
204 KB |
Output is correct |
17 |
Correct |
0 ms |
204 KB |
Output is correct |
18 |
Correct |
0 ms |
204 KB |
Output is correct |
19 |
Correct |
0 ms |
204 KB |
Output is correct |
20 |
Correct |
0 ms |
204 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
204 KB |
Output is correct |
2 |
Correct |
0 ms |
204 KB |
Output is correct |
3 |
Correct |
0 ms |
204 KB |
Output is correct |
4 |
Correct |
0 ms |
204 KB |
Output is correct |
5 |
Correct |
0 ms |
204 KB |
Output is correct |
6 |
Correct |
0 ms |
204 KB |
Output is correct |
7 |
Correct |
0 ms |
204 KB |
Output is correct |
8 |
Correct |
0 ms |
204 KB |
Output is correct |
9 |
Correct |
0 ms |
204 KB |
Output is correct |
10 |
Correct |
0 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 |
0 ms |
204 KB |
Output is correct |
14 |
Correct |
1 ms |
204 KB |
Output is correct |
15 |
Correct |
0 ms |
204 KB |
Output is correct |
16 |
Correct |
0 ms |
204 KB |
Output is correct |
17 |
Correct |
0 ms |
204 KB |
Output is correct |
18 |
Correct |
0 ms |
204 KB |
Output is correct |
19 |
Correct |
0 ms |
204 KB |
Output is correct |
20 |
Correct |
0 ms |
204 KB |
Output is correct |
21 |
Correct |
0 ms |
204 KB |
Output is correct |
22 |
Correct |
1 ms |
460 KB |
Output is correct |
23 |
Correct |
1 ms |
460 KB |
Output is correct |
24 |
Correct |
2 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 |
2 ms |
452 KB |
Output is correct |
28 |
Correct |
2 ms |
464 KB |
Output is correct |
29 |
Correct |
1 ms |
332 KB |
Output is correct |
30 |
Correct |
0 ms |
204 KB |
Output is correct |
31 |
Correct |
2 ms |
460 KB |
Output is correct |
32 |
Correct |
1 ms |
204 KB |
Output is correct |
33 |
Correct |
0 ms |
308 KB |
Output is correct |
34 |
Correct |
0 ms |
204 KB |
Output is correct |
35 |
Correct |
1 ms |
204 KB |
Output is correct |
36 |
Correct |
0 ms |
204 KB |
Output is correct |
37 |
Correct |
1 ms |
332 KB |
Output is correct |
38 |
Correct |
1 ms |
316 KB |
Output is correct |
39 |
Correct |
0 ms |
204 KB |
Output is correct |
40 |
Correct |
0 ms |
204 KB |
Output is correct |
41 |
Correct |
0 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 |
0 ms |
204 KB |
Output is correct |
51 |
Correct |
0 ms |
204 KB |
Output is correct |
52 |
Correct |
1 ms |
312 KB |
Output is correct |
53 |
Correct |
1 ms |
332 KB |
Output is correct |
54 |
Correct |
1 ms |
204 KB |
Output is correct |
55 |
Correct |
1 ms |
332 KB |
Output is correct |
56 |
Correct |
0 ms |
204 KB |
Output is correct |
57 |
Correct |
1 ms |
332 KB |
Output is correct |
58 |
Correct |
1 ms |
460 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
204 KB |
Output is correct |
2 |
Correct |
0 ms |
204 KB |
Output is correct |
3 |
Correct |
0 ms |
204 KB |
Output is correct |
4 |
Correct |
0 ms |
204 KB |
Output is correct |
5 |
Correct |
0 ms |
204 KB |
Output is correct |
6 |
Correct |
0 ms |
204 KB |
Output is correct |
7 |
Correct |
0 ms |
204 KB |
Output is correct |
8 |
Correct |
0 ms |
204 KB |
Output is correct |
9 |
Correct |
0 ms |
204 KB |
Output is correct |
10 |
Correct |
0 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 |
0 ms |
204 KB |
Output is correct |
14 |
Correct |
1 ms |
204 KB |
Output is correct |
15 |
Correct |
0 ms |
204 KB |
Output is correct |
16 |
Correct |
0 ms |
204 KB |
Output is correct |
17 |
Correct |
0 ms |
204 KB |
Output is correct |
18 |
Correct |
0 ms |
204 KB |
Output is correct |
19 |
Correct |
0 ms |
204 KB |
Output is correct |
20 |
Correct |
0 ms |
204 KB |
Output is correct |
21 |
Correct |
0 ms |
204 KB |
Output is correct |
22 |
Correct |
1 ms |
460 KB |
Output is correct |
23 |
Correct |
1 ms |
460 KB |
Output is correct |
24 |
Correct |
2 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 |
2 ms |
452 KB |
Output is correct |
28 |
Correct |
2 ms |
464 KB |
Output is correct |
29 |
Correct |
1 ms |
332 KB |
Output is correct |
30 |
Correct |
0 ms |
204 KB |
Output is correct |
31 |
Correct |
2 ms |
460 KB |
Output is correct |
32 |
Correct |
1 ms |
204 KB |
Output is correct |
33 |
Correct |
0 ms |
308 KB |
Output is correct |
34 |
Correct |
0 ms |
204 KB |
Output is correct |
35 |
Correct |
1 ms |
204 KB |
Output is correct |
36 |
Correct |
0 ms |
204 KB |
Output is correct |
37 |
Correct |
1 ms |
332 KB |
Output is correct |
38 |
Correct |
1 ms |
316 KB |
Output is correct |
39 |
Correct |
0 ms |
204 KB |
Output is correct |
40 |
Correct |
0 ms |
204 KB |
Output is correct |
41 |
Correct |
0 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 |
0 ms |
204 KB |
Output is correct |
51 |
Correct |
0 ms |
204 KB |
Output is correct |
52 |
Correct |
1 ms |
312 KB |
Output is correct |
53 |
Correct |
1 ms |
332 KB |
Output is correct |
54 |
Correct |
1 ms |
204 KB |
Output is correct |
55 |
Correct |
1 ms |
332 KB |
Output is correct |
56 |
Correct |
0 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 |
357 ms |
31660 KB |
Output is correct |
60 |
Correct |
435 ms |
35372 KB |
Output is correct |
61 |
Correct |
0 ms |
204 KB |
Output is correct |
62 |
Correct |
0 ms |
204 KB |
Output is correct |
63 |
Correct |
322 ms |
28652 KB |
Output is correct |
64 |
Correct |
2 ms |
844 KB |
Output is correct |
65 |
Correct |
13 ms |
3020 KB |
Output is correct |
66 |
Correct |
118 ms |
22332 KB |
Output is correct |
67 |
Correct |
476 ms |
46236 KB |
Output is correct |
68 |
Correct |
460 ms |
47428 KB |
Output is correct |
69 |
Correct |
7 ms |
1612 KB |
Output is correct |
70 |
Correct |
88 ms |
13480 KB |
Output is correct |
71 |
Correct |
295 ms |
38940 KB |
Output is correct |
72 |
Correct |
328 ms |
37612 KB |
Output is correct |
73 |
Correct |
73 ms |
10692 KB |
Output is correct |
74 |
Correct |
453 ms |
33880 KB |
Output is correct |
75 |
Correct |
24 ms |
5060 KB |
Output is correct |
76 |
Correct |
385 ms |
38584 KB |
Output is correct |
77 |
Correct |
294 ms |
38936 KB |
Output is correct |
78 |
Correct |
23 ms |
5196 KB |
Output is correct |
79 |
Correct |
464 ms |
43992 KB |
Output is correct |
80 |
Correct |
2 ms |
588 KB |
Output is correct |
81 |
Correct |
100 ms |
13448 KB |
Output is correct |
82 |
Correct |
370 ms |
36268 KB |
Output is correct |
83 |
Correct |
447 ms |
33808 KB |
Output is correct |
84 |
Correct |
424 ms |
33816 KB |
Output is correct |
85 |
Correct |
401 ms |
33860 KB |
Output is correct |
86 |
Correct |
474 ms |
35252 KB |
Output is correct |
87 |
Correct |
428 ms |
35324 KB |
Output is correct |