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Submission #146832

# Submission time Handle Problem Language Result Execution time Memory
146832 2019-08-26T10:51:09 Z muhammad_hokimiyon Network (BOI15_net) C++14
63 / 100
 13 ms 9976 KB 
#include <bits/stdc++.h>
//#pragma GCC optimize("Ofast")

#define LL long long
#define se second
#define fi first

using namespace std;

const int N = 2e5 + 7;
const int mod = 1e9 + 7;
const int B = sqrt(N);

int n;
bool used[N];
vector < int > v[N];
vector < int > ans;

void dfs( int x , int p )
{
    if( v[x].size() == 1 && !used[x] ){
        ans.push_back(x);
    }
    used[x] = true;
    for( auto y : v[x] ){
        if( y == p )continue;
        dfs(y , x);
    }
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(NULL);
    //freopen( "input.txt" , "r" , stdin );
    //freopen( "output.txt" , "w" , stdout );

    cin >> n;
    for( int i = 1; i < n; i++ ){
        int x,y;
        cin >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    int x = 1;
    for( int i = 1; i <= n; i++ ){
        if( v[i].size() > 1 ){
            x = i;
        }
    }
    dfs(x , x);
    int k = (ans.size() + 1) / 2;
    cout << ( (int)ans.size() + 1 ) / 2 << "\n";
    for( int i = 0; i < ( ans.size() + 1) / 2; i++ ){
        cout << ans[i] << " " << ans[ (i + k) % (int)ans.size() ] << "\n";
    }
}

Compilation message

net.cpp: In function 'int main()':
net.cpp:54:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for( int i = 0; i < ( ans.size() + 1) / 2; i++ ){
                     ~~^~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 4988 KB Output is correct
2 Correct 6 ms 4984 KB Output is correct
3 Correct 6 ms 5112 KB Output is correct
4 Correct 6 ms 4984 KB Output is correct
5 Correct 7 ms 4984 KB Output is correct
6 Correct 7 ms 4984 KB Output is correct
7 Correct 6 ms 5048 KB Output is correct
8 Correct 7 ms 5112 KB Output is correct
9 Correct 8 ms 4984 KB Output is correct
10 Correct 8 ms 5112 KB Output is correct
11 Correct 6 ms 5112 KB Output is correct
12 Correct 6 ms 4984 KB Output is correct
13 Correct 7 ms 5112 KB Output is correct
14 Correct 7 ms 5112 KB Output is correct
15 Correct 7 ms 4984 KB Output is correct
16 Correct 9 ms 5112 KB Output is correct
17 Correct 8 ms 5112 KB Output is correct
18 Correct 5 ms 4984 KB Output is correct
19 Correct 7 ms 4984 KB Output is correct
20 Correct 6 ms 4984 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 4988 KB Output is correct
2 Correct 6 ms 4984 KB Output is correct
3 Correct 6 ms 5112 KB Output is correct
4 Correct 6 ms 4984 KB Output is correct
5 Correct 7 ms 4984 KB Output is correct
6 Correct 7 ms 4984 KB Output is correct
7 Correct 6 ms 5048 KB Output is correct
8 Correct 7 ms 5112 KB Output is correct
9 Correct 8 ms 4984 KB Output is correct
10 Correct 8 ms 5112 KB Output is correct
11 Correct 6 ms 5112 KB Output is correct
12 Correct 6 ms 4984 KB Output is correct
13 Correct 7 ms 5112 KB Output is correct
14 Correct 7 ms 5112 KB Output is correct
15 Correct 7 ms 4984 KB Output is correct
16 Correct 9 ms 5112 KB Output is correct
17 Correct 8 ms 5112 KB Output is correct
18 Correct 5 ms 4984 KB Output is correct
19 Correct 7 ms 4984 KB Output is correct
20 Correct 6 ms 4984 KB Output is correct
21 Correct 6 ms 4984 KB Output is correct
22 Correct 7 ms 5112 KB Output is correct
23 Correct 7 ms 5240 KB Output is correct
24 Correct 8 ms 5240 KB Output is correct
25 Correct 8 ms 5112 KB Output is correct
26 Correct 7 ms 5112 KB Output is correct
27 Correct 7 ms 5112 KB Output is correct
28 Correct 8 ms 5112 KB Output is correct
29 Correct 7 ms 5112 KB Output is correct
30 Correct 7 ms 5112 KB Output is correct
31 Correct 10 ms 5112 KB Output is correct
32 Correct 6 ms 4984 KB Output is correct
33 Correct 6 ms 4988 KB Output is correct
34 Correct 6 ms 4984 KB Output is correct
35 Correct 6 ms 5112 KB Output is correct
36 Correct 6 ms 4984 KB Output is correct
37 Correct 7 ms 5112 KB Output is correct
38 Correct 8 ms 5112 KB Output is correct
39 Correct 8 ms 5084 KB Output is correct
40 Correct 8 ms 5112 KB Output is correct
41 Correct 8 ms 5112 KB Output is correct
42 Correct 7 ms 5112 KB Output is correct
43 Correct 8 ms 5108 KB Output is correct
44 Correct 6 ms 4984 KB Output is correct
45 Correct 6 ms 4984 KB Output is correct
46 Correct 7 ms 5112 KB Output is correct
47 Correct 7 ms 5112 KB Output is correct
48 Correct 6 ms 4984 KB Output is correct
49 Correct 7 ms 5112 KB Output is correct
50 Correct 6 ms 5112 KB Output is correct
51 Correct 6 ms 5112 KB Output is correct
52 Correct 6 ms 4984 KB Output is correct
53 Correct 7 ms 5116 KB Output is correct
54 Correct 7 ms 5240 KB Output is correct
55 Correct 6 ms 4984 KB Output is correct
56 Correct 6 ms 4984 KB Output is correct
57 Correct 8 ms 4984 KB Output is correct
58 Correct 7 ms 4984 KB Output is correct

Subtask #3
0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 4988 KB Output is correct
2 Correct 6 ms 4984 KB Output is correct
3 Correct 6 ms 5112 KB Output is correct
4 Correct 6 ms 4984 KB Output is correct
5 Correct 7 ms 4984 KB Output is correct
6 Correct 7 ms 4984 KB Output is correct
7 Correct 6 ms 5048 KB Output is correct
8 Correct 7 ms 5112 KB Output is correct
9 Correct 8 ms 4984 KB Output is correct
10 Correct 8 ms 5112 KB Output is correct
11 Correct 6 ms 5112 KB Output is correct
12 Correct 6 ms 4984 KB Output is correct
13 Correct 7 ms 5112 KB Output is correct
14 Correct 7 ms 5112 KB Output is correct
15 Correct 7 ms 4984 KB Output is correct
16 Correct 9 ms 5112 KB Output is correct
17 Correct 8 ms 5112 KB Output is correct
18 Correct 5 ms 4984 KB Output is correct
19 Correct 7 ms 4984 KB Output is correct
20 Correct 6 ms 4984 KB Output is correct
21 Correct 6 ms 4984 KB Output is correct
22 Correct 7 ms 5112 KB Output is correct
23 Correct 7 ms 5240 KB Output is correct
24 Correct 8 ms 5240 KB Output is correct
25 Correct 8 ms 5112 KB Output is correct
26 Correct 7 ms 5112 KB Output is correct
27 Correct 7 ms 5112 KB Output is correct
28 Correct 8 ms 5112 KB Output is correct
29 Correct 7 ms 5112 KB Output is correct
30 Correct 7 ms 5112 KB Output is correct
31 Correct 10 ms 5112 KB Output is correct
32 Correct 6 ms 4984 KB Output is correct
33 Correct 6 ms 4988 KB Output is correct
34 Correct 6 ms 4984 KB Output is correct
35 Correct 6 ms 5112 KB Output is correct
36 Correct 6 ms 4984 KB Output is correct
37 Correct 7 ms 5112 KB Output is correct
38 Correct 8 ms 5112 KB Output is correct
39 Correct 8 ms 5084 KB Output is correct
40 Correct 8 ms 5112 KB Output is correct
41 Correct 8 ms 5112 KB Output is correct
42 Correct 7 ms 5112 KB Output is correct
43 Correct 8 ms 5108 KB Output is correct
44 Correct 6 ms 4984 KB Output is correct
45 Correct 6 ms 4984 KB Output is correct
46 Correct 7 ms 5112 KB Output is correct
47 Correct 7 ms 5112 KB Output is correct
48 Correct 6 ms 4984 KB Output is correct
49 Correct 7 ms 5112 KB Output is correct
50 Correct 6 ms 5112 KB Output is correct
51 Correct 6 ms 5112 KB Output is correct
52 Correct 6 ms 4984 KB Output is correct
53 Correct 7 ms 5116 KB Output is correct
54 Correct 7 ms 5240 KB Output is correct
55 Correct 6 ms 4984 KB Output is correct
56 Correct 6 ms 4984 KB Output is correct
57 Correct 8 ms 4984 KB Output is correct
58 Correct 7 ms 4984 KB Output is correct
59 Runtime error 13 ms 9976 KB Execution killed with signal 11 (could be triggered by violating memory limits)
60 Halted 0 ms 0 KB -