#include <bits/stdc++.h>
#define N 500050
#define f first
#define s second
using namespace std;
typedef pair<int, int> pii;
int n, ponte, cnt, id[N], menor[N], root;
vector<int> grafo[N], leaf;
void dfs(int x, int p)
{
menor[x] = x;
for(auto v: grafo[x])
{
if(v == p) continue;
dfs(v, x);
menor[x] = min(menor[x], menor[v]);
}
}
void dfs2(int x, int p)
{
vector<pii> order;
if(grafo[x].size() == 1) leaf.push_back(x);
for(auto v: grafo[x])
{
if(v == p) continue;
order.push_back({menor[v], v});
}
sort(order.begin(), order.end());
for(auto v: order) dfs2(v.s, x);
}
int main()
{
ios::sync_with_stdio(false); cin.tie(0);
cin>>n;
for(int i = 1, a, b; i < n; i++)
{
cin>>a>>b;
grafo[a].push_back(b);
grafo[b].push_back(a);
}
for(int i = 1; i <= n; i++)
{
if(grafo[i].size() <= 1) continue;
root = i;
break;
}
dfs(root, root);
dfs2(root, root);
cout<<(ceil(leaf.size()/2.0))<<"\n";
for(int i = 0, j = ((leaf.size()/2)); i < (ceil(leaf.size()/2.0)); i++, j++)
{
cout<<leaf[i]<<" "<<leaf[j]<<"\n";
}
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
13 ms |
12024 KB |
Output is correct |
2 |
Correct |
13 ms |
12136 KB |
Output is correct |
3 |
Correct |
15 ms |
12136 KB |
Output is correct |
4 |
Correct |
13 ms |
12192 KB |
Output is correct |
5 |
Correct |
16 ms |
12284 KB |
Output is correct |
6 |
Correct |
13 ms |
12284 KB |
Output is correct |
7 |
Correct |
13 ms |
12528 KB |
Output is correct |
8 |
Correct |
13 ms |
12528 KB |
Output is correct |
9 |
Correct |
13 ms |
12528 KB |
Output is correct |
10 |
Correct |
14 ms |
12528 KB |
Output is correct |
11 |
Correct |
16 ms |
12528 KB |
Output is correct |
12 |
Correct |
13 ms |
12528 KB |
Output is correct |
13 |
Correct |
14 ms |
12528 KB |
Output is correct |
14 |
Correct |
15 ms |
12528 KB |
Output is correct |
15 |
Correct |
15 ms |
12528 KB |
Output is correct |
16 |
Correct |
14 ms |
12528 KB |
Output is correct |
17 |
Correct |
15 ms |
12528 KB |
Output is correct |
18 |
Correct |
15 ms |
12528 KB |
Output is correct |
19 |
Correct |
15 ms |
12528 KB |
Output is correct |
20 |
Correct |
16 ms |
12616 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
13 ms |
12024 KB |
Output is correct |
2 |
Correct |
13 ms |
12136 KB |
Output is correct |
3 |
Correct |
15 ms |
12136 KB |
Output is correct |
4 |
Correct |
13 ms |
12192 KB |
Output is correct |
5 |
Correct |
16 ms |
12284 KB |
Output is correct |
6 |
Correct |
13 ms |
12284 KB |
Output is correct |
7 |
Correct |
13 ms |
12528 KB |
Output is correct |
8 |
Correct |
13 ms |
12528 KB |
Output is correct |
9 |
Correct |
13 ms |
12528 KB |
Output is correct |
10 |
Correct |
14 ms |
12528 KB |
Output is correct |
11 |
Correct |
16 ms |
12528 KB |
Output is correct |
12 |
Correct |
13 ms |
12528 KB |
Output is correct |
13 |
Correct |
14 ms |
12528 KB |
Output is correct |
14 |
Correct |
15 ms |
12528 KB |
Output is correct |
15 |
Correct |
15 ms |
12528 KB |
Output is correct |
16 |
Correct |
14 ms |
12528 KB |
Output is correct |
17 |
Correct |
15 ms |
12528 KB |
Output is correct |
18 |
Correct |
15 ms |
12528 KB |
Output is correct |
19 |
Correct |
15 ms |
12528 KB |
Output is correct |
20 |
Correct |
16 ms |
12616 KB |
Output is correct |
21 |
Correct |
16 ms |
12616 KB |
Output is correct |
22 |
Correct |
15 ms |
12740 KB |
Output is correct |
23 |
Correct |
16 ms |
12776 KB |
Output is correct |
24 |
Correct |
16 ms |
12812 KB |
Output is correct |
25 |
Correct |
17 ms |
12812 KB |
Output is correct |
26 |
Correct |
14 ms |
12812 KB |
Output is correct |
27 |
Correct |
17 ms |
12820 KB |
Output is correct |
28 |
Correct |
16 ms |
12820 KB |
Output is correct |
29 |
Correct |
14 ms |
12820 KB |
Output is correct |
30 |
Correct |
13 ms |
12820 KB |
Output is correct |
31 |
Correct |
16 ms |
12840 KB |
Output is correct |
32 |
Correct |
13 ms |
12840 KB |
Output is correct |
33 |
Correct |
14 ms |
12848 KB |
Output is correct |
34 |
Correct |
15 ms |
12848 KB |
Output is correct |
35 |
Correct |
14 ms |
12848 KB |
Output is correct |
36 |
Correct |
17 ms |
12848 KB |
Output is correct |
37 |
Correct |
13 ms |
12864 KB |
Output is correct |
38 |
Correct |
14 ms |
12872 KB |
Output is correct |
39 |
Correct |
14 ms |
12872 KB |
Output is correct |
40 |
Correct |
13 ms |
12872 KB |
Output is correct |
41 |
Correct |
15 ms |
12872 KB |
Output is correct |
42 |
Correct |
14 ms |
12892 KB |
Output is correct |
43 |
Correct |
15 ms |
12896 KB |
Output is correct |
44 |
Correct |
15 ms |
12896 KB |
Output is correct |
45 |
Correct |
15 ms |
12908 KB |
Output is correct |
46 |
Correct |
16 ms |
12912 KB |
Output is correct |
47 |
Correct |
16 ms |
12912 KB |
Output is correct |
48 |
Correct |
15 ms |
12924 KB |
Output is correct |
49 |
Correct |
14 ms |
12932 KB |
Output is correct |
50 |
Correct |
16 ms |
12944 KB |
Output is correct |
51 |
Correct |
15 ms |
12944 KB |
Output is correct |
52 |
Correct |
15 ms |
12952 KB |
Output is correct |
53 |
Correct |
15 ms |
12956 KB |
Output is correct |
54 |
Correct |
14 ms |
12956 KB |
Output is correct |
55 |
Correct |
14 ms |
12968 KB |
Output is correct |
56 |
Correct |
17 ms |
12968 KB |
Output is correct |
57 |
Correct |
14 ms |
12976 KB |
Output is correct |
58 |
Correct |
17 ms |
12980 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
13 ms |
12024 KB |
Output is correct |
2 |
Correct |
13 ms |
12136 KB |
Output is correct |
3 |
Correct |
15 ms |
12136 KB |
Output is correct |
4 |
Correct |
13 ms |
12192 KB |
Output is correct |
5 |
Correct |
16 ms |
12284 KB |
Output is correct |
6 |
Correct |
13 ms |
12284 KB |
Output is correct |
7 |
Correct |
13 ms |
12528 KB |
Output is correct |
8 |
Correct |
13 ms |
12528 KB |
Output is correct |
9 |
Correct |
13 ms |
12528 KB |
Output is correct |
10 |
Correct |
14 ms |
12528 KB |
Output is correct |
11 |
Correct |
16 ms |
12528 KB |
Output is correct |
12 |
Correct |
13 ms |
12528 KB |
Output is correct |
13 |
Correct |
14 ms |
12528 KB |
Output is correct |
14 |
Correct |
15 ms |
12528 KB |
Output is correct |
15 |
Correct |
15 ms |
12528 KB |
Output is correct |
16 |
Correct |
14 ms |
12528 KB |
Output is correct |
17 |
Correct |
15 ms |
12528 KB |
Output is correct |
18 |
Correct |
15 ms |
12528 KB |
Output is correct |
19 |
Correct |
15 ms |
12528 KB |
Output is correct |
20 |
Correct |
16 ms |
12616 KB |
Output is correct |
21 |
Correct |
16 ms |
12616 KB |
Output is correct |
22 |
Correct |
15 ms |
12740 KB |
Output is correct |
23 |
Correct |
16 ms |
12776 KB |
Output is correct |
24 |
Correct |
16 ms |
12812 KB |
Output is correct |
25 |
Correct |
17 ms |
12812 KB |
Output is correct |
26 |
Correct |
14 ms |
12812 KB |
Output is correct |
27 |
Correct |
17 ms |
12820 KB |
Output is correct |
28 |
Correct |
16 ms |
12820 KB |
Output is correct |
29 |
Correct |
14 ms |
12820 KB |
Output is correct |
30 |
Correct |
13 ms |
12820 KB |
Output is correct |
31 |
Correct |
16 ms |
12840 KB |
Output is correct |
32 |
Correct |
13 ms |
12840 KB |
Output is correct |
33 |
Correct |
14 ms |
12848 KB |
Output is correct |
34 |
Correct |
15 ms |
12848 KB |
Output is correct |
35 |
Correct |
14 ms |
12848 KB |
Output is correct |
36 |
Correct |
17 ms |
12848 KB |
Output is correct |
37 |
Correct |
13 ms |
12864 KB |
Output is correct |
38 |
Correct |
14 ms |
12872 KB |
Output is correct |
39 |
Correct |
14 ms |
12872 KB |
Output is correct |
40 |
Correct |
13 ms |
12872 KB |
Output is correct |
41 |
Correct |
15 ms |
12872 KB |
Output is correct |
42 |
Correct |
14 ms |
12892 KB |
Output is correct |
43 |
Correct |
15 ms |
12896 KB |
Output is correct |
44 |
Correct |
15 ms |
12896 KB |
Output is correct |
45 |
Correct |
15 ms |
12908 KB |
Output is correct |
46 |
Correct |
16 ms |
12912 KB |
Output is correct |
47 |
Correct |
16 ms |
12912 KB |
Output is correct |
48 |
Correct |
15 ms |
12924 KB |
Output is correct |
49 |
Correct |
14 ms |
12932 KB |
Output is correct |
50 |
Correct |
16 ms |
12944 KB |
Output is correct |
51 |
Correct |
15 ms |
12944 KB |
Output is correct |
52 |
Correct |
15 ms |
12952 KB |
Output is correct |
53 |
Correct |
15 ms |
12956 KB |
Output is correct |
54 |
Correct |
14 ms |
12956 KB |
Output is correct |
55 |
Correct |
14 ms |
12968 KB |
Output is correct |
56 |
Correct |
17 ms |
12968 KB |
Output is correct |
57 |
Correct |
14 ms |
12976 KB |
Output is correct |
58 |
Correct |
17 ms |
12980 KB |
Output is correct |
59 |
Correct |
713 ms |
39700 KB |
Output is correct |
60 |
Correct |
824 ms |
47760 KB |
Output is correct |
61 |
Correct |
13 ms |
47760 KB |
Output is correct |
62 |
Correct |
13 ms |
47760 KB |
Output is correct |
63 |
Correct |
605 ms |
48804 KB |
Output is correct |
64 |
Correct |
20 ms |
48804 KB |
Output is correct |
65 |
Correct |
36 ms |
48804 KB |
Output is correct |
66 |
Correct |
326 ms |
63644 KB |
Output is correct |
67 |
Correct |
981 ms |
95540 KB |
Output is correct |
68 |
Correct |
978 ms |
102972 KB |
Output is correct |
69 |
Correct |
22 ms |
102972 KB |
Output is correct |
70 |
Correct |
151 ms |
102972 KB |
Output is correct |
71 |
Correct |
590 ms |
102972 KB |
Output is correct |
72 |
Correct |
546 ms |
102972 KB |
Output is correct |
73 |
Correct |
199 ms |
102972 KB |
Output is correct |
74 |
Correct |
864 ms |
102972 KB |
Output is correct |
75 |
Correct |
60 ms |
102972 KB |
Output is correct |
76 |
Correct |
679 ms |
104284 KB |
Output is correct |
77 |
Correct |
562 ms |
111108 KB |
Output is correct |
78 |
Correct |
66 ms |
111108 KB |
Output is correct |
79 |
Correct |
1026 ms |
141684 KB |
Output is correct |
80 |
Correct |
16 ms |
141684 KB |
Output is correct |
81 |
Correct |
190 ms |
141684 KB |
Output is correct |
82 |
Correct |
725 ms |
141684 KB |
Output is correct |
83 |
Correct |
875 ms |
141684 KB |
Output is correct |
84 |
Correct |
800 ms |
141684 KB |
Output is correct |
85 |
Correct |
820 ms |
141684 KB |
Output is correct |
86 |
Correct |
815 ms |
148708 KB |
Output is correct |
87 |
Correct |
713 ms |
155240 KB |
Output is correct |