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Submission #394652

# Submission time Handle Problem Language Result Execution time Memory
394652 2021-04-27T06:48:27 Z xxMen Network (BOI15_net) C++14
100 / 100
 649 ms 64848 KB 
#include "bits/stdc++.h"

using namespace std;

const int MAXN = 500007;

bool odw[MAXN];
int leaves[MAXN];
int numleaves;

vector <int> G[MAXN], S[MAXN];

void dfs(int v)
{
  odw[v] = true;
  if((int)G[v].size() == 1)
    leaves[v] = 1;
  for(auto w : G[v])
    if(odw[w]==false)
    {
      dfs(w);
      leaves[v] += leaves[w];
    }
} 

int findcut(int v)
{
  odw[v] = true;
  for(auto w : G[v])
    if(odw[w] == false)
      if(leaves[w] > numleaves/2)
        return findcut(w);
  return v;
}

void newdfs(int v, int tree)
{
  //cerr << v << " " << tree << "T\n";
  odw[v] = true;
  if((int)G[v].size() == 1)
    S[tree].push_back(v);
  for(auto w : G[v])
    if(odw[w] == false)
      newdfs(w,tree);
}

int subtree;

int cut(int n)
{
  dfs(1);
  for(int i=1; i<=n; i++)
    odw[i] = false;
  int w = findcut(1);
  for(int i=1; i<=n; i++)
    odw[i] = false;
  odw[w] = true;
  for(auto v : G[w])
    newdfs(v,++subtree);
  return w;
}

vector <int> W;

int next(int e, int nn)
{
  e += 2;
  if(e==nn)
    e = 1;
  return e;
}

int main()
{
  int n;
  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);
  }
  for(int i=1; i<=n; i++)
    if((int)G[i].size() == 1)
      numleaves++;
  int res = (numleaves+1)/2;
  printf("%d\n", res);
  cut(n);
  
  W.resize(2*res);
  int e = 0;
  for(int i=1; i<=subtree; i++)
  {
    for(auto ele : S[i])
    {
      W[e] = ele;
      e = next(e,2*res);
      //cerr << ele << "." << e << "\n";
    }
  } 

  if((!W.empty()) and W.back() == 0)
    W.back() = S[1][0];

  for(int i=0; i<(int)W.size(); i+=2)
    printf("%d %d\n", W[i], W[i+1]);
}

Compilation message

net.cpp: In function 'int main()':
net.cpp:76:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   76 |   scanf("%d", &n);
      |   ~~~~~^~~~~~~~~~
net.cpp:90:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   90 |     scanf("%d%d", &a, &b);
      |     ~~~~~^~~~~~~~~~~~~~~~

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 23756 KB Output is correct
2 Correct 14 ms 23796 KB Output is correct
3 Correct 15 ms 23756 KB Output is correct
4 Correct 15 ms 23772 KB Output is correct
5 Correct 15 ms 23756 KB Output is correct
6 Correct 14 ms 23756 KB Output is correct
7 Correct 14 ms 23784 KB Output is correct
8 Correct 16 ms 23756 KB Output is correct
9 Correct 15 ms 23792 KB Output is correct
10 Correct 17 ms 23756 KB Output is correct
11 Correct 14 ms 23756 KB Output is correct
12 Correct 14 ms 23760 KB Output is correct
13 Correct 14 ms 23764 KB Output is correct
14 Correct 13 ms 23796 KB Output is correct
15 Correct 14 ms 23756 KB Output is correct
16 Correct 14 ms 23756 KB Output is correct
17 Correct 15 ms 23792 KB Output is correct
18 Correct 14 ms 23756 KB Output is correct
19 Correct 14 ms 23756 KB Output is correct
20 Correct 14 ms 23676 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 23756 KB Output is correct
2 Correct 14 ms 23796 KB Output is correct
3 Correct 15 ms 23756 KB Output is correct
4 Correct 15 ms 23772 KB Output is correct
5 Correct 15 ms 23756 KB Output is correct
6 Correct 14 ms 23756 KB Output is correct
7 Correct 14 ms 23784 KB Output is correct
8 Correct 16 ms 23756 KB Output is correct
9 Correct 15 ms 23792 KB Output is correct
10 Correct 17 ms 23756 KB Output is correct
11 Correct 14 ms 23756 KB Output is correct
12 Correct 14 ms 23760 KB Output is correct
13 Correct 14 ms 23764 KB Output is correct
14 Correct 13 ms 23796 KB Output is correct
15 Correct 14 ms 23756 KB Output is correct
16 Correct 14 ms 23756 KB Output is correct
17 Correct 15 ms 23792 KB Output is correct
18 Correct 14 ms 23756 KB Output is correct
19 Correct 14 ms 23756 KB Output is correct
20 Correct 14 ms 23676 KB Output is correct
21 Correct 15 ms 23796 KB Output is correct
22 Correct 16 ms 23920 KB Output is correct
23 Correct 16 ms 23888 KB Output is correct
24 Correct 16 ms 23940 KB Output is correct
25 Correct 16 ms 23888 KB Output is correct
26 Correct 16 ms 23756 KB Output is correct
27 Correct 17 ms 23768 KB Output is correct
28 Correct 16 ms 23852 KB Output is correct
29 Correct 16 ms 23744 KB Output is correct
30 Correct 16 ms 23884 KB Output is correct
31 Correct 16 ms 23772 KB Output is correct
32 Correct 15 ms 23792 KB Output is correct
33 Correct 15 ms 23756 KB Output is correct
34 Correct 15 ms 23756 KB Output is correct
35 Correct 15 ms 23748 KB Output is correct
36 Correct 14 ms 23728 KB Output is correct
37 Correct 15 ms 23756 KB Output is correct
38 Correct 16 ms 23760 KB Output is correct
39 Correct 15 ms 23680 KB Output is correct
40 Correct 15 ms 23756 KB Output is correct
41 Correct 14 ms 23756 KB Output is correct
42 Correct 15 ms 23836 KB Output is correct
43 Correct 14 ms 23872 KB Output is correct
44 Correct 15 ms 23788 KB Output is correct
45 Correct 15 ms 23756 KB Output is correct
46 Correct 15 ms 23756 KB Output is correct
47 Correct 14 ms 23756 KB Output is correct
48 Correct 14 ms 23720 KB Output is correct
49 Correct 15 ms 23756 KB Output is correct
50 Correct 15 ms 23792 KB Output is correct
51 Correct 15 ms 23784 KB Output is correct
52 Correct 15 ms 23884 KB Output is correct
53 Correct 15 ms 23756 KB Output is correct
54 Correct 14 ms 23756 KB Output is correct
55 Correct 14 ms 23756 KB Output is correct
56 Correct 15 ms 23756 KB Output is correct
57 Correct 15 ms 23788 KB Output is correct
58 Correct 15 ms 23884 KB Output is correct

Subtask #3
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 23756 KB Output is correct
2 Correct 14 ms 23796 KB Output is correct
3 Correct 15 ms 23756 KB Output is correct
4 Correct 15 ms 23772 KB Output is correct
5 Correct 15 ms 23756 KB Output is correct
6 Correct 14 ms 23756 KB Output is correct
7 Correct 14 ms 23784 KB Output is correct
8 Correct 16 ms 23756 KB Output is correct
9 Correct 15 ms 23792 KB Output is correct
10 Correct 17 ms 23756 KB Output is correct
11 Correct 14 ms 23756 KB Output is correct
12 Correct 14 ms 23760 KB Output is correct
13 Correct 14 ms 23764 KB Output is correct
14 Correct 13 ms 23796 KB Output is correct
15 Correct 14 ms 23756 KB Output is correct
16 Correct 14 ms 23756 KB Output is correct
17 Correct 15 ms 23792 KB Output is correct
18 Correct 14 ms 23756 KB Output is correct
19 Correct 14 ms 23756 KB Output is correct
20 Correct 14 ms 23676 KB Output is correct
21 Correct 15 ms 23796 KB Output is correct
22 Correct 16 ms 23920 KB Output is correct
23 Correct 16 ms 23888 KB Output is correct
24 Correct 16 ms 23940 KB Output is correct
25 Correct 16 ms 23888 KB Output is correct
26 Correct 16 ms 23756 KB Output is correct
27 Correct 17 ms 23768 KB Output is correct
28 Correct 16 ms 23852 KB Output is correct
29 Correct 16 ms 23744 KB Output is correct
30 Correct 16 ms 23884 KB Output is correct
31 Correct 16 ms 23772 KB Output is correct
32 Correct 15 ms 23792 KB Output is correct
33 Correct 15 ms 23756 KB Output is correct
34 Correct 15 ms 23756 KB Output is correct
35 Correct 15 ms 23748 KB Output is correct
36 Correct 14 ms 23728 KB Output is correct
37 Correct 15 ms 23756 KB Output is correct
38 Correct 16 ms 23760 KB Output is correct
39 Correct 15 ms 23680 KB Output is correct
40 Correct 15 ms 23756 KB Output is correct
41 Correct 14 ms 23756 KB Output is correct
42 Correct 15 ms 23836 KB Output is correct
43 Correct 14 ms 23872 KB Output is correct
44 Correct 15 ms 23788 KB Output is correct
45 Correct 15 ms 23756 KB Output is correct
46 Correct 15 ms 23756 KB Output is correct
47 Correct 14 ms 23756 KB Output is correct
48 Correct 14 ms 23720 KB Output is correct
49 Correct 15 ms 23756 KB Output is correct
50 Correct 15 ms 23792 KB Output is correct
51 Correct 15 ms 23784 KB Output is correct
52 Correct 15 ms 23884 KB Output is correct
53 Correct 15 ms 23756 KB Output is correct
54 Correct 14 ms 23756 KB Output is correct
55 Correct 14 ms 23756 KB Output is correct
56 Correct 15 ms 23756 KB Output is correct
57 Correct 15 ms 23788 KB Output is correct
58 Correct 15 ms 23884 KB Output is correct
59 Correct 462 ms 48544 KB Output is correct
60 Correct 537 ms 47952 KB Output is correct
61 Correct 15 ms 23756 KB Output is correct
62 Correct 15 ms 23784 KB Output is correct
63 Correct 412 ms 45040 KB Output is correct
64 Correct 21 ms 24164 KB Output is correct
65 Correct 32 ms 25788 KB Output is correct
66 Correct 194 ms 41088 KB Output is correct
67 Correct 621 ms 58760 KB Output is correct
68 Correct 649 ms 59708 KB Output is correct
69 Correct 23 ms 24908 KB Output is correct
70 Correct 119 ms 35880 KB Output is correct
71 Correct 481 ms 64848 KB Output is correct
72 Correct 459 ms 62400 KB Output is correct
73 Correct 110 ms 30024 KB Output is correct
74 Correct 556 ms 46336 KB Output is correct
75 Correct 43 ms 27284 KB Output is correct
76 Correct 407 ms 57228 KB Output is correct
77 Correct 395 ms 57932 KB Output is correct
78 Correct 46 ms 26980 KB Output is correct
79 Correct 647 ms 56312 KB Output is correct
80 Correct 17 ms 24012 KB Output is correct
81 Correct 135 ms 34360 KB Output is correct
82 Correct 503 ms 55608 KB Output is correct
83 Correct 557 ms 46216 KB Output is correct
84 Correct 555 ms 46376 KB Output is correct
85 Correct 563 ms 46504 KB Output is correct
86 Correct 540 ms 47584 KB Output is correct
87 Correct 531 ms 47936 KB Output is correct