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);
                          ^

Subtask #1
18.0 / 18.0

#	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

Subtask #2
45.0 / 45.0

#	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

Subtask #3
0 / 37.0

#	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	-

Submission #22985

Compilation message

Subtask #1 18.0 / 18.0

Subtask #2 45.0 / 45.0

Subtask #3 0 / 37.0

Subtask #1
18.0 / 18.0

Subtask #2
45.0 / 45.0

Subtask #3
0 / 37.0