#include<bits/stdc++.h>
#define fi first
#define se second
using namespace std;
const int nmax = 500005;
vector<int>adj[nmax];
vector<int>leaf;
void DFS() {
stack<pair<int,int>>st;
st.push({1,0});
while(!st.empty()) {
int nod = st.top().fi;
int par = st.top().se;
st.pop();
if(adj[nod].size()==1) leaf.push_back(nod);
for(auto nxt:adj[nod]) {
if(nxt != par) st.push({nxt,nod});
}
}
}
int main() {
int n,a,b;
cin >> n;
for(int i=1; i<n; i++) {
cin >> a >> b;
adj[a].push_back(b);
adj[b].push_back(a);
}
DFS();
int N = (leaf.size()+1)/2;
cout << N << endl;
for(int i=0; i<N; i++) {
cout << leaf[i] << " " << leaf[i+(leaf.size()/2)] << endl;
}
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
5 ms |
11988 KB |
Output is correct |
2 |
Correct |
5 ms |
11988 KB |
Output is correct |
3 |
Correct |
6 ms |
11988 KB |
Output is correct |
4 |
Correct |
6 ms |
11952 KB |
Output is correct |
5 |
Correct |
5 ms |
12000 KB |
Output is correct |
6 |
Correct |
6 ms |
11988 KB |
Output is correct |
7 |
Correct |
7 ms |
11988 KB |
Output is correct |
8 |
Correct |
6 ms |
11988 KB |
Output is correct |
9 |
Correct |
8 ms |
11988 KB |
Output is correct |
10 |
Correct |
7 ms |
12008 KB |
Output is correct |
11 |
Correct |
7 ms |
11988 KB |
Output is correct |
12 |
Correct |
5 ms |
11988 KB |
Output is correct |
13 |
Correct |
7 ms |
12032 KB |
Output is correct |
14 |
Correct |
6 ms |
11988 KB |
Output is correct |
15 |
Correct |
6 ms |
12044 KB |
Output is correct |
16 |
Correct |
5 ms |
11988 KB |
Output is correct |
17 |
Correct |
7 ms |
11940 KB |
Output is correct |
18 |
Correct |
6 ms |
11988 KB |
Output is correct |
19 |
Correct |
7 ms |
12028 KB |
Output is correct |
20 |
Correct |
7 ms |
12104 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
5 ms |
11988 KB |
Output is correct |
2 |
Correct |
5 ms |
11988 KB |
Output is correct |
3 |
Correct |
6 ms |
11988 KB |
Output is correct |
4 |
Correct |
6 ms |
11952 KB |
Output is correct |
5 |
Correct |
5 ms |
12000 KB |
Output is correct |
6 |
Correct |
6 ms |
11988 KB |
Output is correct |
7 |
Correct |
7 ms |
11988 KB |
Output is correct |
8 |
Correct |
6 ms |
11988 KB |
Output is correct |
9 |
Correct |
8 ms |
11988 KB |
Output is correct |
10 |
Correct |
7 ms |
12008 KB |
Output is correct |
11 |
Correct |
7 ms |
11988 KB |
Output is correct |
12 |
Correct |
5 ms |
11988 KB |
Output is correct |
13 |
Correct |
7 ms |
12032 KB |
Output is correct |
14 |
Correct |
6 ms |
11988 KB |
Output is correct |
15 |
Correct |
6 ms |
12044 KB |
Output is correct |
16 |
Correct |
5 ms |
11988 KB |
Output is correct |
17 |
Correct |
7 ms |
11940 KB |
Output is correct |
18 |
Correct |
6 ms |
11988 KB |
Output is correct |
19 |
Correct |
7 ms |
12028 KB |
Output is correct |
20 |
Correct |
7 ms |
12104 KB |
Output is correct |
21 |
Correct |
6 ms |
11988 KB |
Output is correct |
22 |
Correct |
9 ms |
12112 KB |
Output is correct |
23 |
Correct |
8 ms |
12048 KB |
Output is correct |
24 |
Correct |
9 ms |
12068 KB |
Output is correct |
25 |
Correct |
8 ms |
12096 KB |
Output is correct |
26 |
Correct |
7 ms |
12116 KB |
Output is correct |
27 |
Correct |
8 ms |
12116 KB |
Output is correct |
28 |
Correct |
9 ms |
12052 KB |
Output is correct |
29 |
Correct |
7 ms |
11988 KB |
Output is correct |
30 |
Correct |
7 ms |
11988 KB |
Output is correct |
31 |
Correct |
8 ms |
12104 KB |
Output is correct |
32 |
Correct |
6 ms |
12032 KB |
Output is correct |
33 |
Correct |
7 ms |
11988 KB |
Output is correct |
34 |
Correct |
6 ms |
11996 KB |
Output is correct |
35 |
Correct |
6 ms |
11988 KB |
Output is correct |
36 |
Correct |
7 ms |
11988 KB |
Output is correct |
37 |
Correct |
5 ms |
11988 KB |
Output is correct |
38 |
Correct |
6 ms |
11988 KB |
Output is correct |
39 |
Correct |
6 ms |
11988 KB |
Output is correct |
40 |
Correct |
7 ms |
11988 KB |
Output is correct |
41 |
Correct |
6 ms |
11988 KB |
Output is correct |
42 |
Correct |
8 ms |
12004 KB |
Output is correct |
43 |
Correct |
8 ms |
11988 KB |
Output is correct |
44 |
Correct |
6 ms |
11988 KB |
Output is correct |
45 |
Correct |
6 ms |
12048 KB |
Output is correct |
46 |
Correct |
7 ms |
12088 KB |
Output is correct |
47 |
Correct |
8 ms |
12020 KB |
Output is correct |
48 |
Correct |
6 ms |
12044 KB |
Output is correct |
49 |
Correct |
6 ms |
11988 KB |
Output is correct |
50 |
Correct |
6 ms |
11988 KB |
Output is correct |
51 |
Correct |
7 ms |
11988 KB |
Output is correct |
52 |
Correct |
6 ms |
11988 KB |
Output is correct |
53 |
Correct |
6 ms |
11988 KB |
Output is correct |
54 |
Correct |
7 ms |
11988 KB |
Output is correct |
55 |
Correct |
6 ms |
12044 KB |
Output is correct |
56 |
Correct |
6 ms |
11988 KB |
Output is correct |
57 |
Correct |
6 ms |
11988 KB |
Output is correct |
58 |
Correct |
10 ms |
12160 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
5 ms |
11988 KB |
Output is correct |
2 |
Correct |
5 ms |
11988 KB |
Output is correct |
3 |
Correct |
6 ms |
11988 KB |
Output is correct |
4 |
Correct |
6 ms |
11952 KB |
Output is correct |
5 |
Correct |
5 ms |
12000 KB |
Output is correct |
6 |
Correct |
6 ms |
11988 KB |
Output is correct |
7 |
Correct |
7 ms |
11988 KB |
Output is correct |
8 |
Correct |
6 ms |
11988 KB |
Output is correct |
9 |
Correct |
8 ms |
11988 KB |
Output is correct |
10 |
Correct |
7 ms |
12008 KB |
Output is correct |
11 |
Correct |
7 ms |
11988 KB |
Output is correct |
12 |
Correct |
5 ms |
11988 KB |
Output is correct |
13 |
Correct |
7 ms |
12032 KB |
Output is correct |
14 |
Correct |
6 ms |
11988 KB |
Output is correct |
15 |
Correct |
6 ms |
12044 KB |
Output is correct |
16 |
Correct |
5 ms |
11988 KB |
Output is correct |
17 |
Correct |
7 ms |
11940 KB |
Output is correct |
18 |
Correct |
6 ms |
11988 KB |
Output is correct |
19 |
Correct |
7 ms |
12028 KB |
Output is correct |
20 |
Correct |
7 ms |
12104 KB |
Output is correct |
21 |
Correct |
6 ms |
11988 KB |
Output is correct |
22 |
Correct |
9 ms |
12112 KB |
Output is correct |
23 |
Correct |
8 ms |
12048 KB |
Output is correct |
24 |
Correct |
9 ms |
12068 KB |
Output is correct |
25 |
Correct |
8 ms |
12096 KB |
Output is correct |
26 |
Correct |
7 ms |
12116 KB |
Output is correct |
27 |
Correct |
8 ms |
12116 KB |
Output is correct |
28 |
Correct |
9 ms |
12052 KB |
Output is correct |
29 |
Correct |
7 ms |
11988 KB |
Output is correct |
30 |
Correct |
7 ms |
11988 KB |
Output is correct |
31 |
Correct |
8 ms |
12104 KB |
Output is correct |
32 |
Correct |
6 ms |
12032 KB |
Output is correct |
33 |
Correct |
7 ms |
11988 KB |
Output is correct |
34 |
Correct |
6 ms |
11996 KB |
Output is correct |
35 |
Correct |
6 ms |
11988 KB |
Output is correct |
36 |
Correct |
7 ms |
11988 KB |
Output is correct |
37 |
Correct |
5 ms |
11988 KB |
Output is correct |
38 |
Correct |
6 ms |
11988 KB |
Output is correct |
39 |
Correct |
6 ms |
11988 KB |
Output is correct |
40 |
Correct |
7 ms |
11988 KB |
Output is correct |
41 |
Correct |
6 ms |
11988 KB |
Output is correct |
42 |
Correct |
8 ms |
12004 KB |
Output is correct |
43 |
Correct |
8 ms |
11988 KB |
Output is correct |
44 |
Correct |
6 ms |
11988 KB |
Output is correct |
45 |
Correct |
6 ms |
12048 KB |
Output is correct |
46 |
Correct |
7 ms |
12088 KB |
Output is correct |
47 |
Correct |
8 ms |
12020 KB |
Output is correct |
48 |
Correct |
6 ms |
12044 KB |
Output is correct |
49 |
Correct |
6 ms |
11988 KB |
Output is correct |
50 |
Correct |
6 ms |
11988 KB |
Output is correct |
51 |
Correct |
7 ms |
11988 KB |
Output is correct |
52 |
Correct |
6 ms |
11988 KB |
Output is correct |
53 |
Correct |
6 ms |
11988 KB |
Output is correct |
54 |
Correct |
7 ms |
11988 KB |
Output is correct |
55 |
Correct |
6 ms |
12044 KB |
Output is correct |
56 |
Correct |
6 ms |
11988 KB |
Output is correct |
57 |
Correct |
6 ms |
11988 KB |
Output is correct |
58 |
Correct |
10 ms |
12160 KB |
Output is correct |
59 |
Correct |
602 ms |
31684 KB |
Output is correct |
60 |
Correct |
703 ms |
32464 KB |
Output is correct |
61 |
Correct |
6 ms |
11976 KB |
Output is correct |
62 |
Correct |
7 ms |
11988 KB |
Output is correct |
63 |
Correct |
605 ms |
29376 KB |
Output is correct |
64 |
Correct |
9 ms |
12224 KB |
Output is correct |
65 |
Correct |
20 ms |
12740 KB |
Output is correct |
66 |
Correct |
188 ms |
17800 KB |
Output is correct |
67 |
Correct |
616 ms |
28052 KB |
Output is correct |
68 |
Correct |
624 ms |
28640 KB |
Output is correct |
69 |
Correct |
26 ms |
12868 KB |
Output is correct |
70 |
Correct |
221 ms |
20424 KB |
Output is correct |
71 |
Correct |
713 ms |
41272 KB |
Output is correct |
72 |
Correct |
688 ms |
38400 KB |
Output is correct |
73 |
Correct |
146 ms |
17484 KB |
Output is correct |
74 |
Correct |
697 ms |
31280 KB |
Output is correct |
75 |
Correct |
68 ms |
14972 KB |
Output is correct |
76 |
Correct |
679 ms |
38684 KB |
Output is correct |
77 |
Correct |
692 ms |
38908 KB |
Output is correct |
78 |
Correct |
56 ms |
13952 KB |
Output is correct |
79 |
Correct |
643 ms |
27868 KB |
Output is correct |
80 |
Correct |
15 ms |
12244 KB |
Output is correct |
81 |
Correct |
273 ms |
20420 KB |
Output is correct |
82 |
Correct |
754 ms |
36264 KB |
Output is correct |
83 |
Correct |
675 ms |
31504 KB |
Output is correct |
84 |
Correct |
683 ms |
31560 KB |
Output is correct |
85 |
Correct |
693 ms |
31532 KB |
Output is correct |
86 |
Correct |
743 ms |
32612 KB |
Output is correct |
87 |
Correct |
714 ms |
32588 KB |
Output is correct |