#include "bits/stdc++.h"
using namespace std;
typedef long long ll;
typedef long double ld;
#define endl '\n'
#define pb push_back
#define mk make_pair
#define sz size()
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define kill(x) return cout << x << endl, void();
#define int ll
typedef pair <int, int> pii;
#pragma GCC optimize ("O3")
#pragma GCC optimize ("unroll-loops")
#pragma GCC target ("avx2")
const int N = 1e6 + 5;
const int MOD = 998244353, INF = 2e9, MOD2 = 1e9 + 7, sq = 350;
int st[N];
int t;
vector <int> adj[N];
vector <pii> vct;
void dfs (int v, int par)
{
st[v] = t++;
for (int u : adj[v])
if (u != par)
dfs (u, v);
}
void Solve ()
{
int n, v, u;
cin >> n;
for (int i = 1; i < n; i++)
{
cin >> v >> u;
v--, u--;
adj[v].pb (u);
adj[u].pb (v);
}
for (int i = 0; i < n; i++)
if (adj[i].sz > 1)
v = i;
dfs (v, -1);
for (int i = 0; i < n; i++)
if (adj[i].sz == 1)
vct.pb (mk (st[i], i));
sort (all (vct));
cout << (vct.sz + 1) / 2 << endl;
if (vct.sz % 2)
cout << vct.back ().S + 1 << ' ' << vct[0].S + 1 << endl;
for (int i = 0; i < vct.sz / 2; i++)
cout << vct[i].S + 1 << ' ' << vct[i + vct.sz / 2].S + 1 << endl;
}
int32_t main ()
{
ios::sync_with_stdio (0), cin.tie (0), cout.tie (0);
int tt = 1;
// cin >> tt;
while (tt--)
Solve ();
}
Compilation message
net.cpp: In function 'void Solve()':
net.cpp:59:20: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
59 | for (int i = 0; i < vct.sz / 2; i++)
| ~~^~~~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
12 ms |
23764 KB |
Output is correct |
2 |
Correct |
13 ms |
23764 KB |
Output is correct |
3 |
Correct |
12 ms |
23764 KB |
Output is correct |
4 |
Correct |
12 ms |
23704 KB |
Output is correct |
5 |
Correct |
14 ms |
23764 KB |
Output is correct |
6 |
Correct |
12 ms |
23808 KB |
Output is correct |
7 |
Correct |
14 ms |
23764 KB |
Output is correct |
8 |
Correct |
14 ms |
23764 KB |
Output is correct |
9 |
Correct |
13 ms |
23764 KB |
Output is correct |
10 |
Correct |
13 ms |
23764 KB |
Output is correct |
11 |
Correct |
13 ms |
23788 KB |
Output is correct |
12 |
Correct |
12 ms |
23764 KB |
Output is correct |
13 |
Correct |
12 ms |
23712 KB |
Output is correct |
14 |
Correct |
12 ms |
23764 KB |
Output is correct |
15 |
Correct |
12 ms |
23760 KB |
Output is correct |
16 |
Correct |
12 ms |
23764 KB |
Output is correct |
17 |
Correct |
14 ms |
23740 KB |
Output is correct |
18 |
Correct |
12 ms |
23764 KB |
Output is correct |
19 |
Correct |
14 ms |
23692 KB |
Output is correct |
20 |
Correct |
12 ms |
23728 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
12 ms |
23764 KB |
Output is correct |
2 |
Correct |
13 ms |
23764 KB |
Output is correct |
3 |
Correct |
12 ms |
23764 KB |
Output is correct |
4 |
Correct |
12 ms |
23704 KB |
Output is correct |
5 |
Correct |
14 ms |
23764 KB |
Output is correct |
6 |
Correct |
12 ms |
23808 KB |
Output is correct |
7 |
Correct |
14 ms |
23764 KB |
Output is correct |
8 |
Correct |
14 ms |
23764 KB |
Output is correct |
9 |
Correct |
13 ms |
23764 KB |
Output is correct |
10 |
Correct |
13 ms |
23764 KB |
Output is correct |
11 |
Correct |
13 ms |
23788 KB |
Output is correct |
12 |
Correct |
12 ms |
23764 KB |
Output is correct |
13 |
Correct |
12 ms |
23712 KB |
Output is correct |
14 |
Correct |
12 ms |
23764 KB |
Output is correct |
15 |
Correct |
12 ms |
23760 KB |
Output is correct |
16 |
Correct |
12 ms |
23764 KB |
Output is correct |
17 |
Correct |
14 ms |
23740 KB |
Output is correct |
18 |
Correct |
12 ms |
23764 KB |
Output is correct |
19 |
Correct |
14 ms |
23692 KB |
Output is correct |
20 |
Correct |
12 ms |
23728 KB |
Output is correct |
21 |
Correct |
13 ms |
23764 KB |
Output is correct |
22 |
Correct |
13 ms |
23892 KB |
Output is correct |
23 |
Correct |
13 ms |
23984 KB |
Output is correct |
24 |
Correct |
12 ms |
23892 KB |
Output is correct |
25 |
Correct |
13 ms |
23892 KB |
Output is correct |
26 |
Correct |
13 ms |
23892 KB |
Output is correct |
27 |
Correct |
13 ms |
23932 KB |
Output is correct |
28 |
Correct |
13 ms |
23892 KB |
Output is correct |
29 |
Correct |
12 ms |
23892 KB |
Output is correct |
30 |
Correct |
12 ms |
23764 KB |
Output is correct |
31 |
Correct |
13 ms |
23964 KB |
Output is correct |
32 |
Correct |
12 ms |
23764 KB |
Output is correct |
33 |
Correct |
12 ms |
23720 KB |
Output is correct |
34 |
Correct |
13 ms |
23712 KB |
Output is correct |
35 |
Correct |
13 ms |
23764 KB |
Output is correct |
36 |
Correct |
12 ms |
23764 KB |
Output is correct |
37 |
Correct |
12 ms |
23764 KB |
Output is correct |
38 |
Correct |
12 ms |
23876 KB |
Output is correct |
39 |
Correct |
12 ms |
23716 KB |
Output is correct |
40 |
Correct |
13 ms |
23892 KB |
Output is correct |
41 |
Correct |
12 ms |
23784 KB |
Output is correct |
42 |
Correct |
12 ms |
23780 KB |
Output is correct |
43 |
Correct |
12 ms |
23804 KB |
Output is correct |
44 |
Correct |
12 ms |
23760 KB |
Output is correct |
45 |
Correct |
12 ms |
23764 KB |
Output is correct |
46 |
Correct |
12 ms |
23752 KB |
Output is correct |
47 |
Correct |
12 ms |
23728 KB |
Output is correct |
48 |
Correct |
14 ms |
23764 KB |
Output is correct |
49 |
Correct |
12 ms |
23892 KB |
Output is correct |
50 |
Correct |
12 ms |
23764 KB |
Output is correct |
51 |
Correct |
12 ms |
23764 KB |
Output is correct |
52 |
Correct |
11 ms |
23832 KB |
Output is correct |
53 |
Correct |
13 ms |
23764 KB |
Output is correct |
54 |
Correct |
11 ms |
23804 KB |
Output is correct |
55 |
Correct |
12 ms |
23764 KB |
Output is correct |
56 |
Correct |
11 ms |
23764 KB |
Output is correct |
57 |
Correct |
13 ms |
23832 KB |
Output is correct |
58 |
Correct |
13 ms |
23892 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
12 ms |
23764 KB |
Output is correct |
2 |
Correct |
13 ms |
23764 KB |
Output is correct |
3 |
Correct |
12 ms |
23764 KB |
Output is correct |
4 |
Correct |
12 ms |
23704 KB |
Output is correct |
5 |
Correct |
14 ms |
23764 KB |
Output is correct |
6 |
Correct |
12 ms |
23808 KB |
Output is correct |
7 |
Correct |
14 ms |
23764 KB |
Output is correct |
8 |
Correct |
14 ms |
23764 KB |
Output is correct |
9 |
Correct |
13 ms |
23764 KB |
Output is correct |
10 |
Correct |
13 ms |
23764 KB |
Output is correct |
11 |
Correct |
13 ms |
23788 KB |
Output is correct |
12 |
Correct |
12 ms |
23764 KB |
Output is correct |
13 |
Correct |
12 ms |
23712 KB |
Output is correct |
14 |
Correct |
12 ms |
23764 KB |
Output is correct |
15 |
Correct |
12 ms |
23760 KB |
Output is correct |
16 |
Correct |
12 ms |
23764 KB |
Output is correct |
17 |
Correct |
14 ms |
23740 KB |
Output is correct |
18 |
Correct |
12 ms |
23764 KB |
Output is correct |
19 |
Correct |
14 ms |
23692 KB |
Output is correct |
20 |
Correct |
12 ms |
23728 KB |
Output is correct |
21 |
Correct |
13 ms |
23764 KB |
Output is correct |
22 |
Correct |
13 ms |
23892 KB |
Output is correct |
23 |
Correct |
13 ms |
23984 KB |
Output is correct |
24 |
Correct |
12 ms |
23892 KB |
Output is correct |
25 |
Correct |
13 ms |
23892 KB |
Output is correct |
26 |
Correct |
13 ms |
23892 KB |
Output is correct |
27 |
Correct |
13 ms |
23932 KB |
Output is correct |
28 |
Correct |
13 ms |
23892 KB |
Output is correct |
29 |
Correct |
12 ms |
23892 KB |
Output is correct |
30 |
Correct |
12 ms |
23764 KB |
Output is correct |
31 |
Correct |
13 ms |
23964 KB |
Output is correct |
32 |
Correct |
12 ms |
23764 KB |
Output is correct |
33 |
Correct |
12 ms |
23720 KB |
Output is correct |
34 |
Correct |
13 ms |
23712 KB |
Output is correct |
35 |
Correct |
13 ms |
23764 KB |
Output is correct |
36 |
Correct |
12 ms |
23764 KB |
Output is correct |
37 |
Correct |
12 ms |
23764 KB |
Output is correct |
38 |
Correct |
12 ms |
23876 KB |
Output is correct |
39 |
Correct |
12 ms |
23716 KB |
Output is correct |
40 |
Correct |
13 ms |
23892 KB |
Output is correct |
41 |
Correct |
12 ms |
23784 KB |
Output is correct |
42 |
Correct |
12 ms |
23780 KB |
Output is correct |
43 |
Correct |
12 ms |
23804 KB |
Output is correct |
44 |
Correct |
12 ms |
23760 KB |
Output is correct |
45 |
Correct |
12 ms |
23764 KB |
Output is correct |
46 |
Correct |
12 ms |
23752 KB |
Output is correct |
47 |
Correct |
12 ms |
23728 KB |
Output is correct |
48 |
Correct |
14 ms |
23764 KB |
Output is correct |
49 |
Correct |
12 ms |
23892 KB |
Output is correct |
50 |
Correct |
12 ms |
23764 KB |
Output is correct |
51 |
Correct |
12 ms |
23764 KB |
Output is correct |
52 |
Correct |
11 ms |
23832 KB |
Output is correct |
53 |
Correct |
13 ms |
23764 KB |
Output is correct |
54 |
Correct |
11 ms |
23804 KB |
Output is correct |
55 |
Correct |
12 ms |
23764 KB |
Output is correct |
56 |
Correct |
11 ms |
23764 KB |
Output is correct |
57 |
Correct |
13 ms |
23832 KB |
Output is correct |
58 |
Correct |
13 ms |
23892 KB |
Output is correct |
59 |
Correct |
317 ms |
53640 KB |
Output is correct |
60 |
Correct |
383 ms |
55740 KB |
Output is correct |
61 |
Correct |
12 ms |
23764 KB |
Output is correct |
62 |
Correct |
12 ms |
23764 KB |
Output is correct |
63 |
Correct |
280 ms |
50164 KB |
Output is correct |
64 |
Correct |
14 ms |
24020 KB |
Output is correct |
65 |
Correct |
20 ms |
25204 KB |
Output is correct |
66 |
Correct |
112 ms |
33996 KB |
Output is correct |
67 |
Correct |
422 ms |
57256 KB |
Output is correct |
68 |
Correct |
403 ms |
54620 KB |
Output is correct |
69 |
Correct |
18 ms |
24916 KB |
Output is correct |
70 |
Correct |
82 ms |
35324 KB |
Output is correct |
71 |
Correct |
286 ms |
58696 KB |
Output is correct |
72 |
Correct |
294 ms |
57092 KB |
Output is correct |
73 |
Correct |
83 ms |
32192 KB |
Output is correct |
74 |
Correct |
386 ms |
52208 KB |
Output is correct |
75 |
Correct |
34 ms |
27592 KB |
Output is correct |
76 |
Correct |
304 ms |
58084 KB |
Output is correct |
77 |
Correct |
293 ms |
58620 KB |
Output is correct |
78 |
Correct |
33 ms |
26964 KB |
Output is correct |
79 |
Correct |
387 ms |
49620 KB |
Output is correct |
80 |
Correct |
14 ms |
24148 KB |
Output is correct |
81 |
Correct |
98 ms |
34484 KB |
Output is correct |
82 |
Correct |
339 ms |
55384 KB |
Output is correct |
83 |
Correct |
407 ms |
52156 KB |
Output is correct |
84 |
Correct |
439 ms |
52140 KB |
Output is correct |
85 |
Correct |
399 ms |
52140 KB |
Output is correct |
86 |
Correct |
411 ms |
55848 KB |
Output is correct |
87 |
Correct |
439 ms |
55752 KB |
Output is correct |