/**
* author: 3omar_ahmed
* date: 09-09-2022
* Expert When :)
*/
#include <bits/stdc++.h>
using namespace std ;
#define int long long
#define endl '\n'
#define all(a) a.begin() , a.end()
#define alr(a) a.rbegin() , a.rend()
int n ;
vector < vector < int >> adj(500001);
vector < int > a;
void dfs(int node , int par){
if(adj[node].size() == 1){
a.push_back(node);
}
for(auto i : adj[node]){
if(i == par) continue ;
dfs(i , node);
}
}
signed main(){
ios_base::sync_with_stdio(0); cin.tie(0);cout.tie(0);
cin >> n;
for(int i = 1 ; i < n ; i++){
int u , v;
cin >> u >> v;
adj[u].push_back(v);
adj[v].push_back(u);
}
dfs(1 , 0);
// for(auto i : a) cout << i << ' ';
// cout << endl;
cout << ((int)(a.size()) + 1) / 2 << endl;
for(int i = 0 ; i < a.size() / 2 ; i ++){
cout << a[i] << ' ' << a[((int)(a.size()) + 1) / 2 + i] << endl;
}
if((int)(a.size()) % 2 == 0) return 0;
int val = a[a.size() / 2];
set < int > s ;
for(int i = 1 ; i <= n ; i++){
if(count(all(adj[val]),i))
continue ;
val = i ;
break ;
}
cout << a[a.size() / 2] << ' ' << val << endl;
return 0 ;
}
Compilation message
net.cpp: In function 'int main()':
net.cpp:38:23: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
38 | for(int i = 0 ; i < a.size() / 2 ; i ++){
| ~~^~~~~~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
6 ms |
11988 KB |
Output is correct |
2 |
Correct |
7 ms |
11988 KB |
Output is correct |
3 |
Correct |
8 ms |
11988 KB |
Output is correct |
4 |
Correct |
6 ms |
12072 KB |
Output is correct |
5 |
Correct |
8 ms |
11988 KB |
Output is correct |
6 |
Correct |
7 ms |
11988 KB |
Output is correct |
7 |
Correct |
7 ms |
11988 KB |
Output is correct |
8 |
Correct |
7 ms |
11988 KB |
Output is correct |
9 |
Correct |
7 ms |
11988 KB |
Output is correct |
10 |
Correct |
7 ms |
11988 KB |
Output is correct |
11 |
Correct |
6 ms |
11988 KB |
Output is correct |
12 |
Correct |
6 ms |
11988 KB |
Output is correct |
13 |
Correct |
6 ms |
11988 KB |
Output is correct |
14 |
Correct |
7 ms |
12040 KB |
Output is correct |
15 |
Correct |
7 ms |
11988 KB |
Output is correct |
16 |
Correct |
8 ms |
12012 KB |
Output is correct |
17 |
Correct |
7 ms |
11988 KB |
Output is correct |
18 |
Correct |
6 ms |
11988 KB |
Output is correct |
19 |
Correct |
7 ms |
12016 KB |
Output is correct |
20 |
Correct |
6 ms |
11988 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
6 ms |
11988 KB |
Output is correct |
2 |
Correct |
7 ms |
11988 KB |
Output is correct |
3 |
Correct |
8 ms |
11988 KB |
Output is correct |
4 |
Correct |
6 ms |
12072 KB |
Output is correct |
5 |
Correct |
8 ms |
11988 KB |
Output is correct |
6 |
Correct |
7 ms |
11988 KB |
Output is correct |
7 |
Correct |
7 ms |
11988 KB |
Output is correct |
8 |
Correct |
7 ms |
11988 KB |
Output is correct |
9 |
Correct |
7 ms |
11988 KB |
Output is correct |
10 |
Correct |
7 ms |
11988 KB |
Output is correct |
11 |
Correct |
6 ms |
11988 KB |
Output is correct |
12 |
Correct |
6 ms |
11988 KB |
Output is correct |
13 |
Correct |
6 ms |
11988 KB |
Output is correct |
14 |
Correct |
7 ms |
12040 KB |
Output is correct |
15 |
Correct |
7 ms |
11988 KB |
Output is correct |
16 |
Correct |
8 ms |
12012 KB |
Output is correct |
17 |
Correct |
7 ms |
11988 KB |
Output is correct |
18 |
Correct |
6 ms |
11988 KB |
Output is correct |
19 |
Correct |
7 ms |
12016 KB |
Output is correct |
20 |
Correct |
6 ms |
11988 KB |
Output is correct |
21 |
Correct |
6 ms |
11988 KB |
Output is correct |
22 |
Correct |
7 ms |
12216 KB |
Output is correct |
23 |
Correct |
8 ms |
12116 KB |
Output is correct |
24 |
Correct |
9 ms |
12116 KB |
Output is correct |
25 |
Correct |
8 ms |
12196 KB |
Output is correct |
26 |
Correct |
7 ms |
12084 KB |
Output is correct |
27 |
Correct |
7 ms |
12116 KB |
Output is correct |
28 |
Correct |
8 ms |
12088 KB |
Output is correct |
29 |
Correct |
7 ms |
12080 KB |
Output is correct |
30 |
Correct |
7 ms |
11988 KB |
Output is correct |
31 |
Correct |
8 ms |
12116 KB |
Output is correct |
32 |
Correct |
7 ms |
11988 KB |
Output is correct |
33 |
Correct |
6 ms |
11988 KB |
Output is correct |
34 |
Correct |
6 ms |
11988 KB |
Output is correct |
35 |
Correct |
7 ms |
11988 KB |
Output is correct |
36 |
Correct |
7 ms |
11988 KB |
Output is correct |
37 |
Correct |
6 ms |
12080 KB |
Output is correct |
38 |
Correct |
7 ms |
12116 KB |
Output is correct |
39 |
Correct |
6 ms |
12032 KB |
Output is correct |
40 |
Correct |
6 ms |
11988 KB |
Output is correct |
41 |
Correct |
8 ms |
11988 KB |
Output is correct |
42 |
Correct |
7 ms |
11988 KB |
Output is correct |
43 |
Correct |
7 ms |
12064 KB |
Output is correct |
44 |
Correct |
7 ms |
11988 KB |
Output is correct |
45 |
Correct |
7 ms |
12068 KB |
Output is correct |
46 |
Correct |
7 ms |
12116 KB |
Output is correct |
47 |
Correct |
7 ms |
12008 KB |
Output is correct |
48 |
Correct |
8 ms |
11988 KB |
Output is correct |
49 |
Correct |
7 ms |
12088 KB |
Output is correct |
50 |
Correct |
6 ms |
11988 KB |
Output is correct |
51 |
Correct |
6 ms |
11988 KB |
Output is correct |
52 |
Correct |
6 ms |
11988 KB |
Output is correct |
53 |
Correct |
7 ms |
12116 KB |
Output is correct |
54 |
Correct |
7 ms |
11988 KB |
Output is correct |
55 |
Correct |
6 ms |
11988 KB |
Output is correct |
56 |
Correct |
6 ms |
11988 KB |
Output is correct |
57 |
Correct |
8 ms |
12076 KB |
Output is correct |
58 |
Correct |
8 ms |
12212 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
6 ms |
11988 KB |
Output is correct |
2 |
Correct |
7 ms |
11988 KB |
Output is correct |
3 |
Correct |
8 ms |
11988 KB |
Output is correct |
4 |
Correct |
6 ms |
12072 KB |
Output is correct |
5 |
Correct |
8 ms |
11988 KB |
Output is correct |
6 |
Correct |
7 ms |
11988 KB |
Output is correct |
7 |
Correct |
7 ms |
11988 KB |
Output is correct |
8 |
Correct |
7 ms |
11988 KB |
Output is correct |
9 |
Correct |
7 ms |
11988 KB |
Output is correct |
10 |
Correct |
7 ms |
11988 KB |
Output is correct |
11 |
Correct |
6 ms |
11988 KB |
Output is correct |
12 |
Correct |
6 ms |
11988 KB |
Output is correct |
13 |
Correct |
6 ms |
11988 KB |
Output is correct |
14 |
Correct |
7 ms |
12040 KB |
Output is correct |
15 |
Correct |
7 ms |
11988 KB |
Output is correct |
16 |
Correct |
8 ms |
12012 KB |
Output is correct |
17 |
Correct |
7 ms |
11988 KB |
Output is correct |
18 |
Correct |
6 ms |
11988 KB |
Output is correct |
19 |
Correct |
7 ms |
12016 KB |
Output is correct |
20 |
Correct |
6 ms |
11988 KB |
Output is correct |
21 |
Correct |
6 ms |
11988 KB |
Output is correct |
22 |
Correct |
7 ms |
12216 KB |
Output is correct |
23 |
Correct |
8 ms |
12116 KB |
Output is correct |
24 |
Correct |
9 ms |
12116 KB |
Output is correct |
25 |
Correct |
8 ms |
12196 KB |
Output is correct |
26 |
Correct |
7 ms |
12084 KB |
Output is correct |
27 |
Correct |
7 ms |
12116 KB |
Output is correct |
28 |
Correct |
8 ms |
12088 KB |
Output is correct |
29 |
Correct |
7 ms |
12080 KB |
Output is correct |
30 |
Correct |
7 ms |
11988 KB |
Output is correct |
31 |
Correct |
8 ms |
12116 KB |
Output is correct |
32 |
Correct |
7 ms |
11988 KB |
Output is correct |
33 |
Correct |
6 ms |
11988 KB |
Output is correct |
34 |
Correct |
6 ms |
11988 KB |
Output is correct |
35 |
Correct |
7 ms |
11988 KB |
Output is correct |
36 |
Correct |
7 ms |
11988 KB |
Output is correct |
37 |
Correct |
6 ms |
12080 KB |
Output is correct |
38 |
Correct |
7 ms |
12116 KB |
Output is correct |
39 |
Correct |
6 ms |
12032 KB |
Output is correct |
40 |
Correct |
6 ms |
11988 KB |
Output is correct |
41 |
Correct |
8 ms |
11988 KB |
Output is correct |
42 |
Correct |
7 ms |
11988 KB |
Output is correct |
43 |
Correct |
7 ms |
12064 KB |
Output is correct |
44 |
Correct |
7 ms |
11988 KB |
Output is correct |
45 |
Correct |
7 ms |
12068 KB |
Output is correct |
46 |
Correct |
7 ms |
12116 KB |
Output is correct |
47 |
Correct |
7 ms |
12008 KB |
Output is correct |
48 |
Correct |
8 ms |
11988 KB |
Output is correct |
49 |
Correct |
7 ms |
12088 KB |
Output is correct |
50 |
Correct |
6 ms |
11988 KB |
Output is correct |
51 |
Correct |
6 ms |
11988 KB |
Output is correct |
52 |
Correct |
6 ms |
11988 KB |
Output is correct |
53 |
Correct |
7 ms |
12116 KB |
Output is correct |
54 |
Correct |
7 ms |
11988 KB |
Output is correct |
55 |
Correct |
6 ms |
11988 KB |
Output is correct |
56 |
Correct |
6 ms |
11988 KB |
Output is correct |
57 |
Correct |
8 ms |
12076 KB |
Output is correct |
58 |
Correct |
8 ms |
12212 KB |
Output is correct |
59 |
Correct |
298 ms |
40504 KB |
Output is correct |
60 |
Correct |
356 ms |
43396 KB |
Output is correct |
61 |
Correct |
7 ms |
11988 KB |
Output is correct |
62 |
Correct |
8 ms |
11988 KB |
Output is correct |
63 |
Correct |
256 ms |
36632 KB |
Output is correct |
64 |
Correct |
8 ms |
12384 KB |
Output is correct |
65 |
Correct |
16 ms |
13836 KB |
Output is correct |
66 |
Correct |
115 ms |
27828 KB |
Output is correct |
67 |
Correct |
408 ms |
46840 KB |
Output is correct |
68 |
Correct |
402 ms |
48496 KB |
Output is correct |
69 |
Correct |
12 ms |
13012 KB |
Output is correct |
70 |
Correct |
68 ms |
23216 KB |
Output is correct |
71 |
Correct |
235 ms |
45788 KB |
Output is correct |
72 |
Correct |
258 ms |
44392 KB |
Output is correct |
73 |
Correct |
79 ms |
20004 KB |
Output is correct |
74 |
Correct |
378 ms |
41096 KB |
Output is correct |
75 |
Correct |
24 ms |
15604 KB |
Output is correct |
76 |
Correct |
256 ms |
45324 KB |
Output is correct |
77 |
Correct |
247 ms |
45496 KB |
Output is correct |
78 |
Correct |
28 ms |
15688 KB |
Output is correct |
79 |
Correct |
418 ms |
45132 KB |
Output is correct |
80 |
Correct |
8 ms |
12228 KB |
Output is correct |
81 |
Correct |
92 ms |
22520 KB |
Output is correct |
82 |
Correct |
356 ms |
43260 KB |
Output is correct |
83 |
Correct |
363 ms |
41060 KB |
Output is correct |
84 |
Correct |
351 ms |
41128 KB |
Output is correct |
85 |
Correct |
347 ms |
41224 KB |
Output is correct |
86 |
Correct |
365 ms |
43432 KB |
Output is correct |
87 |
Correct |
381 ms |
43576 KB |
Output is correct |