#include <bits/stdc++.h>
using namespace std;
template< class T, class T2 > inline bool chkmin( T& a, const T2& b ){ return a > b ? a = b, 1 : 0; }
template< class T, class T2 > inline bool chkmax( T& a, const T2& b ){ return a < b ? a = b, 1 : 0; }
#ifndef LOCAL
#define cerr if( false )cerr
#endif
#define out(x) #x << " = " << x << " "
typedef long long ll;
const int MAX_N = 1e6 + 42;
const ll mod = 1e9 + 7;
std::vector< int > v[MAX_N];
int par[MAX_N];
std::vector< int > leaves;
void dfs( int x, int p = -1 ){
par[x] = p;
if( v[x].size() == 1 ) leaves.push_back( x );
for( auto j : v[x] ){
if( j == p ) continue;
dfs( j, x );
}
}
int main (){
#ifndef LOCAL
std::ios_base::sync_with_stdio( false ); std::cin.tie( NULL ); std::cout.tie( NULL );
#endif
int n;
std::cin >> n;
for( int i=0 ; i < n-1 ; i++ ){
int a, b;
std::cin >> a >> b;
a--; b--;
v[a].push_back( b );
v[b].push_back( a );
}
int st = 0;
dfs( st );
// NE RABOTI
// for( int i=0 ; i < MAX_N ; i++ ){
// if( v[i].size() == 2 ) leaves.push_back( i );
// }
std::cout << ( leaves.size() +1 ) /2 << endl;
int add = leaves.size() >> 1;
for( int i=0 ; i + add < leaves.size() ; i++ ){
std::cout << leaves[i] +1 << " " << leaves[i + add] +1 << endl;
}
return 0;
}
Compilation message
net.cpp: In function 'int main()':
net.cpp:57:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
57 | for( int i=0 ; i + add < leaves.size() ; i++ ){
| ~~~~~~~~^~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
6 ms |
25432 KB |
Output is correct |
| 2 |
Correct |
6 ms |
25520 KB |
Output is correct |
| 3 |
Correct |
6 ms |
25524 KB |
Output is correct |
| 4 |
Correct |
5 ms |
25436 KB |
Output is correct |
| 5 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 6 |
Correct |
6 ms |
25432 KB |
Output is correct |
| 7 |
Correct |
8 ms |
25436 KB |
Output is correct |
| 8 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 9 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 10 |
Correct |
6 ms |
25548 KB |
Output is correct |
| 11 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 12 |
Correct |
5 ms |
25436 KB |
Output is correct |
| 13 |
Correct |
5 ms |
25436 KB |
Output is correct |
| 14 |
Correct |
7 ms |
25540 KB |
Output is correct |
| 15 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 16 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 17 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 18 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 19 |
Correct |
6 ms |
25432 KB |
Output is correct |
| 20 |
Correct |
6 ms |
25436 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
6 ms |
25432 KB |
Output is correct |
| 2 |
Correct |
6 ms |
25520 KB |
Output is correct |
| 3 |
Correct |
6 ms |
25524 KB |
Output is correct |
| 4 |
Correct |
5 ms |
25436 KB |
Output is correct |
| 5 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 6 |
Correct |
6 ms |
25432 KB |
Output is correct |
| 7 |
Correct |
8 ms |
25436 KB |
Output is correct |
| 8 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 9 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 10 |
Correct |
6 ms |
25548 KB |
Output is correct |
| 11 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 12 |
Correct |
5 ms |
25436 KB |
Output is correct |
| 13 |
Correct |
5 ms |
25436 KB |
Output is correct |
| 14 |
Correct |
7 ms |
25540 KB |
Output is correct |
| 15 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 16 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 17 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 18 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 19 |
Correct |
6 ms |
25432 KB |
Output is correct |
| 20 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 21 |
Correct |
7 ms |
25432 KB |
Output is correct |
| 22 |
Correct |
9 ms |
25692 KB |
Output is correct |
| 23 |
Correct |
10 ms |
25692 KB |
Output is correct |
| 24 |
Correct |
7 ms |
25692 KB |
Output is correct |
| 25 |
Correct |
7 ms |
25688 KB |
Output is correct |
| 26 |
Correct |
7 ms |
25436 KB |
Output is correct |
| 27 |
Correct |
7 ms |
25692 KB |
Output is correct |
| 28 |
Correct |
7 ms |
25692 KB |
Output is correct |
| 29 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 30 |
Correct |
5 ms |
25436 KB |
Output is correct |
| 31 |
Correct |
7 ms |
25692 KB |
Output is correct |
| 32 |
Correct |
5 ms |
25436 KB |
Output is correct |
| 33 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 34 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 35 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 36 |
Correct |
6 ms |
25556 KB |
Output is correct |
| 37 |
Correct |
5 ms |
25436 KB |
Output is correct |
| 38 |
Correct |
5 ms |
25436 KB |
Output is correct |
| 39 |
Correct |
7 ms |
25552 KB |
Output is correct |
| 40 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 41 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 42 |
Correct |
7 ms |
25436 KB |
Output is correct |
| 43 |
Correct |
7 ms |
25552 KB |
Output is correct |
| 44 |
Correct |
5 ms |
25432 KB |
Output is correct |
| 45 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 46 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 47 |
Correct |
5 ms |
25436 KB |
Output is correct |
| 48 |
Correct |
5 ms |
25568 KB |
Output is correct |
| 49 |
Correct |
6 ms |
25432 KB |
Output is correct |
| 50 |
Correct |
5 ms |
25436 KB |
Output is correct |
| 51 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 52 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 53 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 54 |
Correct |
5 ms |
25436 KB |
Output is correct |
| 55 |
Correct |
7 ms |
25436 KB |
Output is correct |
| 56 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 57 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 58 |
Correct |
7 ms |
25692 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
6 ms |
25432 KB |
Output is correct |
| 2 |
Correct |
6 ms |
25520 KB |
Output is correct |
| 3 |
Correct |
6 ms |
25524 KB |
Output is correct |
| 4 |
Correct |
5 ms |
25436 KB |
Output is correct |
| 5 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 6 |
Correct |
6 ms |
25432 KB |
Output is correct |
| 7 |
Correct |
8 ms |
25436 KB |
Output is correct |
| 8 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 9 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 10 |
Correct |
6 ms |
25548 KB |
Output is correct |
| 11 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 12 |
Correct |
5 ms |
25436 KB |
Output is correct |
| 13 |
Correct |
5 ms |
25436 KB |
Output is correct |
| 14 |
Correct |
7 ms |
25540 KB |
Output is correct |
| 15 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 16 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 17 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 18 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 19 |
Correct |
6 ms |
25432 KB |
Output is correct |
| 20 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 21 |
Correct |
7 ms |
25432 KB |
Output is correct |
| 22 |
Correct |
9 ms |
25692 KB |
Output is correct |
| 23 |
Correct |
10 ms |
25692 KB |
Output is correct |
| 24 |
Correct |
7 ms |
25692 KB |
Output is correct |
| 25 |
Correct |
7 ms |
25688 KB |
Output is correct |
| 26 |
Correct |
7 ms |
25436 KB |
Output is correct |
| 27 |
Correct |
7 ms |
25692 KB |
Output is correct |
| 28 |
Correct |
7 ms |
25692 KB |
Output is correct |
| 29 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 30 |
Correct |
5 ms |
25436 KB |
Output is correct |
| 31 |
Correct |
7 ms |
25692 KB |
Output is correct |
| 32 |
Correct |
5 ms |
25436 KB |
Output is correct |
| 33 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 34 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 35 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 36 |
Correct |
6 ms |
25556 KB |
Output is correct |
| 37 |
Correct |
5 ms |
25436 KB |
Output is correct |
| 38 |
Correct |
5 ms |
25436 KB |
Output is correct |
| 39 |
Correct |
7 ms |
25552 KB |
Output is correct |
| 40 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 41 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 42 |
Correct |
7 ms |
25436 KB |
Output is correct |
| 43 |
Correct |
7 ms |
25552 KB |
Output is correct |
| 44 |
Correct |
5 ms |
25432 KB |
Output is correct |
| 45 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 46 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 47 |
Correct |
5 ms |
25436 KB |
Output is correct |
| 48 |
Correct |
5 ms |
25568 KB |
Output is correct |
| 49 |
Correct |
6 ms |
25432 KB |
Output is correct |
| 50 |
Correct |
5 ms |
25436 KB |
Output is correct |
| 51 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 52 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 53 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 54 |
Correct |
5 ms |
25436 KB |
Output is correct |
| 55 |
Correct |
7 ms |
25436 KB |
Output is correct |
| 56 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 57 |
Correct |
6 ms |
25436 KB |
Output is correct |
| 58 |
Correct |
7 ms |
25692 KB |
Output is correct |
| 59 |
Correct |
385 ms |
45624 KB |
Output is correct |
| 60 |
Correct |
446 ms |
48008 KB |
Output is correct |
| 61 |
Correct |
6 ms |
25432 KB |
Output is correct |
| 62 |
Correct |
6 ms |
25508 KB |
Output is correct |
| 63 |
Correct |
380 ms |
43900 KB |
Output is correct |
| 64 |
Correct |
7 ms |
25948 KB |
Output is correct |
| 65 |
Correct |
13 ms |
27228 KB |
Output is correct |
| 66 |
Correct |
89 ms |
41488 KB |
Output is correct |
| 67 |
Correct |
341 ms |
55888 KB |
Output is correct |
| 68 |
Correct |
374 ms |
56724 KB |
Output is correct |
| 69 |
Correct |
18 ms |
26204 KB |
Output is correct |
| 70 |
Correct |
126 ms |
34996 KB |
Output is correct |
| 71 |
Correct |
449 ms |
50956 KB |
Output is correct |
| 72 |
Correct |
443 ms |
50088 KB |
Output is correct |
| 73 |
Correct |
89 ms |
32992 KB |
Output is correct |
| 74 |
Correct |
443 ms |
46744 KB |
Output is correct |
| 75 |
Correct |
48 ms |
30420 KB |
Output is correct |
| 76 |
Correct |
436 ms |
50584 KB |
Output is correct |
| 77 |
Correct |
483 ms |
50900 KB |
Output is correct |
| 78 |
Correct |
29 ms |
30300 KB |
Output is correct |
| 79 |
Correct |
325 ms |
54100 KB |
Output is correct |
| 80 |
Correct |
8 ms |
25692 KB |
Output is correct |
| 81 |
Correct |
128 ms |
34892 KB |
Output is correct |
| 82 |
Correct |
439 ms |
48840 KB |
Output is correct |
| 83 |
Correct |
422 ms |
46732 KB |
Output is correct |
| 84 |
Correct |
425 ms |
46868 KB |
Output is correct |
| 85 |
Correct |
488 ms |
46832 KB |
Output is correct |
| 86 |
Correct |
488 ms |
47888 KB |
Output is correct |
| 87 |
Correct |
519 ms |
47844 KB |
Output is correct |
