Submission #22985

# Submission time Handle Problem Language Result Execution time Memory
22985 2017-05-01T02:38:58 Z model_code Network (BOI15_net) C++11
63 / 100
1136 ms 64512 KB
/*/
  Task: net
  Random solution
  With covering edges
  Author: Bartosz Kostka 
/*/

#include "bits/stdc++.h"

using namespace std;

const int MAXN = 500007;

vector <int> L,G[MAXN];
int w, n;

int licz;
int d[MAXN], par[MAXN];
bool vis[MAXN];
map <pair <int, int>, bool> M;

void print(vector <int> &S)
{
  printf("%d\n", (int)S.size()/2);
  for(int i=0; i<(int)S.size(); i+=2)
    printf("%d %d\n", S[i], S[i+1]);
  exit(0);
}

void dfs(int v)
{
  vis[v] = true;
  for(auto w : G[v])
    if(vis[w] == false)
    {
      d[w] = d[v]+1;
      par[w] = v;
      dfs(w);
    }
}

void sset(int a, int b, bool jak)
{
  int x = min(a,b);
  int y = max(a,b);
  M[make_pair(x,y)] = jak;
}

void cover(int a, int b)
{
  if(d[a] < d[b])
    swap(a,b);
  while(d[a] != d[b])
  {
    sset(a,par[a],true);
    a = par[a];
  }
  while(a != b)
  {
    cerr << a << " " << b << "\n";
    cerr << "P" << par[a] << " " << par[b] << "\n";
    sset(a,par[a],true);
    a = par[a];
    sset(b,par[b],true);
    b = par[b];
  }
}

bool bridges()
{
  cerr << "???\n";
  for(auto ele : M)
    if(ele.second == false)
      return true;
  return false;
}

int main()
{
  srand(42);
  scanf("%d", &n);
  if(n==1)
  {
    printf("0\n");
    return 0;
  }
  if(n==2)
  {
    printf("1\n1 2\n");
    return 0;
  }
  for(int i=1; i<n; i++)
  {
    int a, b;
    scanf("%d%d", &a, &b);
    G[a].push_back(b);
    G[b].push_back(a);
    sset(a,b,false);
  }
  for(int i=1; i<=n; i++)
  {
    if((int)G[i].size() == 1)
      L.push_back(i);
    else
      w = i;
  }
  dfs(w);
  if((int)L.size() % 2 == 1)
    L.push_back(w);
  while(true)
  {
    random_shuffle(L.begin(), L.end());
    for(int i=0; i<(int)L.size(); i+=2)
    {
      int a = L[i], b = L[i+1];
      cerr << a << " " << b << "\n";
      cover(a,b);
    }
    if(bridges() == false)
      print(L);
    for(auto& ele : M)
      ele.second = false; 
  } 
}

Compilation message

net.cpp: In function 'int main()':
net.cpp:81:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &n);
                  ^
net.cpp:95:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d", &a, &b);
                          ^
# Verdict Execution time Memory Grader output
1 Correct 6 ms 18140 KB Output is correct
2 Correct 0 ms 18140 KB Output is correct
3 Correct 3 ms 18140 KB Output is correct
4 Correct 0 ms 18140 KB Output is correct
5 Correct 3 ms 18140 KB Output is correct
6 Correct 6 ms 18140 KB Output is correct
7 Correct 0 ms 18140 KB Output is correct
8 Correct 0 ms 18140 KB Output is correct
9 Correct 6 ms 18140 KB Output is correct
10 Correct 0 ms 18140 KB Output is correct
11 Correct 0 ms 18140 KB Output is correct
12 Correct 6 ms 18140 KB Output is correct
13 Correct 0 ms 18140 KB Output is correct
14 Correct 0 ms 18140 KB Output is correct
15 Correct 0 ms 18140 KB Output is correct
16 Correct 3 ms 18140 KB Output is correct
17 Correct 0 ms 18140 KB Output is correct
18 Correct 0 ms 18140 KB Output is correct
19 Correct 3 ms 18140 KB Output is correct
20 Correct 0 ms 18140 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 6 ms 18140 KB Output is correct
2 Correct 0 ms 18140 KB Output is correct
3 Correct 3 ms 18140 KB Output is correct
4 Correct 0 ms 18140 KB Output is correct
5 Correct 3 ms 18140 KB Output is correct
6 Correct 6 ms 18140 KB Output is correct
7 Correct 0 ms 18140 KB Output is correct
8 Correct 0 ms 18140 KB Output is correct
9 Correct 6 ms 18140 KB Output is correct
10 Correct 0 ms 18140 KB Output is correct
11 Correct 0 ms 18140 KB Output is correct
12 Correct 6 ms 18140 KB Output is correct
13 Correct 0 ms 18140 KB Output is correct
14 Correct 0 ms 18140 KB Output is correct
15 Correct 0 ms 18140 KB Output is correct
16 Correct 3 ms 18140 KB Output is correct
17 Correct 0 ms 18140 KB Output is correct
18 Correct 0 ms 18140 KB Output is correct
19 Correct 3 ms 18140 KB Output is correct
20 Correct 0 ms 18140 KB Output is correct
21 Correct 3 ms 18140 KB Output is correct
22 Correct 36 ms 18404 KB Output is correct
23 Correct 23 ms 18404 KB Output is correct
24 Correct 16 ms 18404 KB Output is correct
25 Correct 29 ms 18404 KB Output is correct
26 Correct 13 ms 18272 KB Output is correct
27 Correct 33 ms 18404 KB Output is correct
28 Correct 29 ms 18404 KB Output is correct
29 Correct 13 ms 18272 KB Output is correct
30 Correct 3 ms 18140 KB Output is correct
31 Correct 43 ms 18404 KB Output is correct
32 Correct 0 ms 18140 KB Output is correct
33 Correct 3 ms 18140 KB Output is correct
34 Correct 3 ms 18140 KB Output is correct
35 Correct 0 ms 18140 KB Output is correct
36 Correct 0 ms 18140 KB Output is correct
37 Correct 3 ms 18272 KB Output is correct
38 Correct 19 ms 18272 KB Output is correct
39 Correct 0 ms 18140 KB Output is correct
40 Correct 0 ms 18140 KB Output is correct
41 Correct 6 ms 18140 KB Output is correct
42 Correct 3 ms 18272 KB Output is correct
43 Correct 6 ms 18272 KB Output is correct
44 Correct 0 ms 18140 KB Output is correct
45 Correct 16 ms 18140 KB Output is correct
46 Correct 19 ms 18272 KB Output is correct
47 Correct 3 ms 18140 KB Output is correct
48 Correct 0 ms 18140 KB Output is correct
49 Correct 3 ms 18272 KB Output is correct
50 Correct 0 ms 18140 KB Output is correct
51 Correct 3 ms 18140 KB Output is correct
52 Correct 9 ms 18140 KB Output is correct
53 Correct 36 ms 18272 KB Output is correct
54 Correct 6 ms 18140 KB Output is correct
55 Correct 6 ms 18140 KB Output is correct
56 Correct 0 ms 18140 KB Output is correct
57 Correct 9 ms 18272 KB Output is correct
58 Correct 33 ms 18404 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 6 ms 18140 KB Output is correct
2 Correct 0 ms 18140 KB Output is correct
3 Correct 3 ms 18140 KB Output is correct
4 Correct 0 ms 18140 KB Output is correct
5 Correct 3 ms 18140 KB Output is correct
6 Correct 6 ms 18140 KB Output is correct
7 Correct 0 ms 18140 KB Output is correct
8 Correct 0 ms 18140 KB Output is correct
9 Correct 6 ms 18140 KB Output is correct
10 Correct 0 ms 18140 KB Output is correct
11 Correct 0 ms 18140 KB Output is correct
12 Correct 6 ms 18140 KB Output is correct
13 Correct 0 ms 18140 KB Output is correct
14 Correct 0 ms 18140 KB Output is correct
15 Correct 0 ms 18140 KB Output is correct
16 Correct 3 ms 18140 KB Output is correct
17 Correct 0 ms 18140 KB Output is correct
18 Correct 0 ms 18140 KB Output is correct
19 Correct 3 ms 18140 KB Output is correct
20 Correct 0 ms 18140 KB Output is correct
21 Correct 3 ms 18140 KB Output is correct
22 Correct 36 ms 18404 KB Output is correct
23 Correct 23 ms 18404 KB Output is correct
24 Correct 16 ms 18404 KB Output is correct
25 Correct 29 ms 18404 KB Output is correct
26 Correct 13 ms 18272 KB Output is correct
27 Correct 33 ms 18404 KB Output is correct
28 Correct 29 ms 18404 KB Output is correct
29 Correct 13 ms 18272 KB Output is correct
30 Correct 3 ms 18140 KB Output is correct
31 Correct 43 ms 18404 KB Output is correct
32 Correct 0 ms 18140 KB Output is correct
33 Correct 3 ms 18140 KB Output is correct
34 Correct 3 ms 18140 KB Output is correct
35 Correct 0 ms 18140 KB Output is correct
36 Correct 0 ms 18140 KB Output is correct
37 Correct 3 ms 18272 KB Output is correct
38 Correct 19 ms 18272 KB Output is correct
39 Correct 0 ms 18140 KB Output is correct
40 Correct 0 ms 18140 KB Output is correct
41 Correct 6 ms 18140 KB Output is correct
42 Correct 3 ms 18272 KB Output is correct
43 Correct 6 ms 18272 KB Output is correct
44 Correct 0 ms 18140 KB Output is correct
45 Correct 16 ms 18140 KB Output is correct
46 Correct 19 ms 18272 KB Output is correct
47 Correct 3 ms 18140 KB Output is correct
48 Correct 0 ms 18140 KB Output is correct
49 Correct 3 ms 18272 KB Output is correct
50 Correct 0 ms 18140 KB Output is correct
51 Correct 3 ms 18140 KB Output is correct
52 Correct 9 ms 18140 KB Output is correct
53 Correct 36 ms 18272 KB Output is correct
54 Correct 6 ms 18140 KB Output is correct
55 Correct 6 ms 18140 KB Output is correct
56 Correct 0 ms 18140 KB Output is correct
57 Correct 9 ms 18272 KB Output is correct
58 Correct 33 ms 18404 KB Output is correct
59 Runtime error 1136 ms 64512 KB Execution timed out (wall clock limit exceeded)
60 Halted 0 ms 0 KB -