/*
Baltic 15-net (accepted, looked at solution)
Key ideas:
- Simply link the ith leaf node to the i+(# of leaves)/2 node.
- Account for the case where (# of leaves) is odd.
*/
#include<iostream>
#include<vector>
using namespace std;
vector<int>s;
vector<vector<int>>t;//1 IDX
bool f[500005]={};
int N;
void dfs(int u){
if(f[u])return;
f[u]=1;
if(t[u].size()==1)s.push_back(u);
for(int&i:t[u])dfs(i);
}
int main(){
cin>>N;
for(int i=0;i<=N+5;++i)t.push_back(vector<int>());
for(int i=0;i<N-1;++i){
int a,b;cin>>a>>b;
t[a].push_back(b);
t[b].push_back(a);
}
dfs(1);
int k=s.size();
if(k%2){
cout<<k/2+1<<'\n';
for(int i=0;i<k/2;++i){
cout<<s[i]<<' '<<s[i+k/2+1]<<'\n';
}
cout<<s[k/2]<<' '<<1<<'\n';
}else{
cout<<k/2<<'\n';
for(int i=0;i<k/2;++i){
cout<<s[i]<<' '<<s[i+k/2]<<'\n';
}
}
// free memory
vector<vector<int>>().swap(t);
vector<int>().swap(s);
return 0;
}
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
212 KB |
Output is correct |
| 2 |
Correct |
0 ms |
212 KB |
Output is correct |
| 3 |
Correct |
0 ms |
212 KB |
Output is correct |
| 4 |
Correct |
0 ms |
212 KB |
Output is correct |
| 5 |
Correct |
1 ms |
212 KB |
Output is correct |
| 6 |
Correct |
1 ms |
212 KB |
Output is correct |
| 7 |
Correct |
0 ms |
212 KB |
Output is correct |
| 8 |
Correct |
0 ms |
212 KB |
Output is correct |
| 9 |
Correct |
0 ms |
212 KB |
Output is correct |
| 10 |
Correct |
0 ms |
212 KB |
Output is correct |
| 11 |
Correct |
0 ms |
212 KB |
Output is correct |
| 12 |
Correct |
0 ms |
212 KB |
Output is correct |
| 13 |
Correct |
0 ms |
212 KB |
Output is correct |
| 14 |
Correct |
0 ms |
212 KB |
Output is correct |
| 15 |
Correct |
0 ms |
212 KB |
Output is correct |
| 16 |
Correct |
0 ms |
212 KB |
Output is correct |
| 17 |
Correct |
1 ms |
212 KB |
Output is correct |
| 18 |
Correct |
1 ms |
212 KB |
Output is correct |
| 19 |
Correct |
1 ms |
212 KB |
Output is correct |
| 20 |
Correct |
1 ms |
212 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
212 KB |
Output is correct |
| 2 |
Correct |
0 ms |
212 KB |
Output is correct |
| 3 |
Correct |
0 ms |
212 KB |
Output is correct |
| 4 |
Correct |
0 ms |
212 KB |
Output is correct |
| 5 |
Correct |
1 ms |
212 KB |
Output is correct |
| 6 |
Correct |
1 ms |
212 KB |
Output is correct |
| 7 |
Correct |
0 ms |
212 KB |
Output is correct |
| 8 |
Correct |
0 ms |
212 KB |
Output is correct |
| 9 |
Correct |
0 ms |
212 KB |
Output is correct |
| 10 |
Correct |
0 ms |
212 KB |
Output is correct |
| 11 |
Correct |
0 ms |
212 KB |
Output is correct |
| 12 |
Correct |
0 ms |
212 KB |
Output is correct |
| 13 |
Correct |
0 ms |
212 KB |
Output is correct |
| 14 |
Correct |
0 ms |
212 KB |
Output is correct |
| 15 |
Correct |
0 ms |
212 KB |
Output is correct |
| 16 |
Correct |
0 ms |
212 KB |
Output is correct |
| 17 |
Correct |
1 ms |
212 KB |
Output is correct |
| 18 |
Correct |
1 ms |
212 KB |
Output is correct |
| 19 |
Correct |
1 ms |
212 KB |
Output is correct |
| 20 |
Correct |
1 ms |
212 KB |
Output is correct |
| 21 |
Correct |
0 ms |
212 KB |
Output is correct |
| 22 |
Correct |
2 ms |
340 KB |
Output is correct |
| 23 |
Correct |
2 ms |
340 KB |
Output is correct |
| 24 |
Correct |
2 ms |
340 KB |
Output is correct |
| 25 |
Correct |
2 ms |
340 KB |
Output is correct |
| 26 |
Correct |
1 ms |
340 KB |
Output is correct |
| 27 |
Correct |
2 ms |
340 KB |
Output is correct |
| 28 |
Correct |
1 ms |
340 KB |
Output is correct |
| 29 |
Correct |
1 ms |
340 KB |
Output is correct |
| 30 |
Correct |
0 ms |
212 KB |
Output is correct |
| 31 |
Correct |
2 ms |
400 KB |
Output is correct |
| 32 |
Correct |
0 ms |
212 KB |
Output is correct |
| 33 |
Correct |
0 ms |
212 KB |
Output is correct |
| 34 |
Correct |
1 ms |
212 KB |
Output is correct |
| 35 |
Correct |
1 ms |
212 KB |
Output is correct |
| 36 |
Correct |
1 ms |
212 KB |
Output is correct |
| 37 |
Correct |
1 ms |
340 KB |
Output is correct |
| 38 |
Correct |
1 ms |
308 KB |
Output is correct |
| 39 |
Correct |
1 ms |
308 KB |
Output is correct |
| 40 |
Correct |
1 ms |
212 KB |
Output is correct |
| 41 |
Correct |
1 ms |
308 KB |
Output is correct |
| 42 |
Correct |
1 ms |
340 KB |
Output is correct |
| 43 |
Correct |
1 ms |
340 KB |
Output is correct |
| 44 |
Correct |
1 ms |
212 KB |
Output is correct |
| 45 |
Correct |
1 ms |
304 KB |
Output is correct |
| 46 |
Correct |
1 ms |
340 KB |
Output is correct |
| 47 |
Correct |
1 ms |
212 KB |
Output is correct |
| 48 |
Correct |
1 ms |
340 KB |
Output is correct |
| 49 |
Correct |
1 ms |
340 KB |
Output is correct |
| 50 |
Correct |
1 ms |
212 KB |
Output is correct |
| 51 |
Correct |
1 ms |
212 KB |
Output is correct |
| 52 |
Correct |
1 ms |
340 KB |
Output is correct |
| 53 |
Correct |
1 ms |
340 KB |
Output is correct |
| 54 |
Correct |
1 ms |
212 KB |
Output is correct |
| 55 |
Correct |
1 ms |
340 KB |
Output is correct |
| 56 |
Correct |
1 ms |
212 KB |
Output is correct |
| 57 |
Correct |
1 ms |
340 KB |
Output is correct |
| 58 |
Correct |
2 ms |
468 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
212 KB |
Output is correct |
| 2 |
Correct |
0 ms |
212 KB |
Output is correct |
| 3 |
Correct |
0 ms |
212 KB |
Output is correct |
| 4 |
Correct |
0 ms |
212 KB |
Output is correct |
| 5 |
Correct |
1 ms |
212 KB |
Output is correct |
| 6 |
Correct |
1 ms |
212 KB |
Output is correct |
| 7 |
Correct |
0 ms |
212 KB |
Output is correct |
| 8 |
Correct |
0 ms |
212 KB |
Output is correct |
| 9 |
Correct |
0 ms |
212 KB |
Output is correct |
| 10 |
Correct |
0 ms |
212 KB |
Output is correct |
| 11 |
Correct |
0 ms |
212 KB |
Output is correct |
| 12 |
Correct |
0 ms |
212 KB |
Output is correct |
| 13 |
Correct |
0 ms |
212 KB |
Output is correct |
| 14 |
Correct |
0 ms |
212 KB |
Output is correct |
| 15 |
Correct |
0 ms |
212 KB |
Output is correct |
| 16 |
Correct |
0 ms |
212 KB |
Output is correct |
| 17 |
Correct |
1 ms |
212 KB |
Output is correct |
| 18 |
Correct |
1 ms |
212 KB |
Output is correct |
| 19 |
Correct |
1 ms |
212 KB |
Output is correct |
| 20 |
Correct |
1 ms |
212 KB |
Output is correct |
| 21 |
Correct |
0 ms |
212 KB |
Output is correct |
| 22 |
Correct |
2 ms |
340 KB |
Output is correct |
| 23 |
Correct |
2 ms |
340 KB |
Output is correct |
| 24 |
Correct |
2 ms |
340 KB |
Output is correct |
| 25 |
Correct |
2 ms |
340 KB |
Output is correct |
| 26 |
Correct |
1 ms |
340 KB |
Output is correct |
| 27 |
Correct |
2 ms |
340 KB |
Output is correct |
| 28 |
Correct |
1 ms |
340 KB |
Output is correct |
| 29 |
Correct |
1 ms |
340 KB |
Output is correct |
| 30 |
Correct |
0 ms |
212 KB |
Output is correct |
| 31 |
Correct |
2 ms |
400 KB |
Output is correct |
| 32 |
Correct |
0 ms |
212 KB |
Output is correct |
| 33 |
Correct |
0 ms |
212 KB |
Output is correct |
| 34 |
Correct |
1 ms |
212 KB |
Output is correct |
| 35 |
Correct |
1 ms |
212 KB |
Output is correct |
| 36 |
Correct |
1 ms |
212 KB |
Output is correct |
| 37 |
Correct |
1 ms |
340 KB |
Output is correct |
| 38 |
Correct |
1 ms |
308 KB |
Output is correct |
| 39 |
Correct |
1 ms |
308 KB |
Output is correct |
| 40 |
Correct |
1 ms |
212 KB |
Output is correct |
| 41 |
Correct |
1 ms |
308 KB |
Output is correct |
| 42 |
Correct |
1 ms |
340 KB |
Output is correct |
| 43 |
Correct |
1 ms |
340 KB |
Output is correct |
| 44 |
Correct |
1 ms |
212 KB |
Output is correct |
| 45 |
Correct |
1 ms |
304 KB |
Output is correct |
| 46 |
Correct |
1 ms |
340 KB |
Output is correct |
| 47 |
Correct |
1 ms |
212 KB |
Output is correct |
| 48 |
Correct |
1 ms |
340 KB |
Output is correct |
| 49 |
Correct |
1 ms |
340 KB |
Output is correct |
| 50 |
Correct |
1 ms |
212 KB |
Output is correct |
| 51 |
Correct |
1 ms |
212 KB |
Output is correct |
| 52 |
Correct |
1 ms |
340 KB |
Output is correct |
| 53 |
Correct |
1 ms |
340 KB |
Output is correct |
| 54 |
Correct |
1 ms |
212 KB |
Output is correct |
| 55 |
Correct |
1 ms |
340 KB |
Output is correct |
| 56 |
Correct |
1 ms |
212 KB |
Output is correct |
| 57 |
Correct |
1 ms |
340 KB |
Output is correct |
| 58 |
Correct |
2 ms |
468 KB |
Output is correct |
| 59 |
Correct |
563 ms |
37240 KB |
Output is correct |
| 60 |
Correct |
709 ms |
41148 KB |
Output is correct |
| 61 |
Correct |
1 ms |
212 KB |
Output is correct |
| 62 |
Correct |
1 ms |
212 KB |
Output is correct |
| 63 |
Correct |
500 ms |
33552 KB |
Output is correct |
| 64 |
Correct |
7 ms |
756 KB |
Output is correct |
| 65 |
Correct |
20 ms |
2680 KB |
Output is correct |
| 66 |
Correct |
238 ms |
20488 KB |
Output is correct |
| 67 |
Correct |
698 ms |
47400 KB |
Output is correct |
| 68 |
Correct |
765 ms |
48404 KB |
Output is correct |
| 69 |
Correct |
13 ms |
1488 KB |
Output is correct |
| 70 |
Correct |
153 ms |
14380 KB |
Output is correct |
| 71 |
Correct |
586 ms |
44240 KB |
Output is correct |
| 72 |
Correct |
580 ms |
43036 KB |
Output is correct |
| 73 |
Correct |
125 ms |
11056 KB |
Output is correct |
| 74 |
Correct |
715 ms |
39040 KB |
Output is correct |
| 75 |
Correct |
56 ms |
4992 KB |
Output is correct |
| 76 |
Correct |
648 ms |
43972 KB |
Output is correct |
| 77 |
Correct |
595 ms |
44136 KB |
Output is correct |
| 78 |
Correct |
43 ms |
4924 KB |
Output is correct |
| 79 |
Correct |
662 ms |
45576 KB |
Output is correct |
| 80 |
Correct |
4 ms |
596 KB |
Output is correct |
| 81 |
Correct |
178 ms |
14044 KB |
Output is correct |
| 82 |
Correct |
632 ms |
41856 KB |
Output is correct |
| 83 |
Correct |
660 ms |
39088 KB |
Output is correct |
| 84 |
Correct |
660 ms |
39000 KB |
Output is correct |
| 85 |
Correct |
680 ms |
38948 KB |
Output is correct |
| 86 |
Correct |
682 ms |
41160 KB |
Output is correct |
| 87 |
Correct |
653 ms |
41108 KB |
Output is correct |
