oj.uz

Submission #732076

# Submission time Handle Problem Language Result Execution time Memory
732076 2023-04-28T10:59:55 Z ollel Network (BOI15_net) C++14
100 / 100
 944 ms 72916 KB 

#include <bits/stdc++.h>
using namespace std;
#include <iostream>

typedef vector<int> vi;
typedef vector<vi> vvi;

#define pb push_back
#define rep(i,a,b) for(int i = a; i < b; i++)

int n;
vvi g;
vi leaf;
int total_leafs;
vvi groups;
vi par;

void dfs(int x, int p) {
  par[x] = p;
  for (auto y : g[x]) {
    if (y == p) continue;

    dfs(y, x);
    leaf[x] += leaf[y];
  }
}

void dfs3(int x, int p) {
  par[x] = p;
  for (auto y : g[x]) if (y != p) dfs3(y, x);
}

bool test(int r) {
  for (auto y : g[r]) if (par[r] != y) if (leaf[y] > total_leafs / 2) return false;
  if (total_leafs - leaf[r] > total_leafs / 2) return false;
  return true;
}

void dfs2(int x, int p, vi & group) {
  for (auto y : g[x]) {
    if (y == p) continue;
    dfs2(y, x, group);
  }
  if (g[x].size() == 1) group.pb(x);
}

int main() {
  cin >> n;
  par.resize(n);
  if (n == 2) {
    cout << 1 << "\n" << 1 << " " << 2 << endl;
    exit(0);
  }

  g.resize(n);
  rep(i,0,n-1) {
    int a, b;
    cin >> a >> b;
    a--;b--;
    g[a].pb(b);
    g[b].pb(a);
  }

  leaf.assign(n, 0);
  rep(i,0,n) if (g[i].size() == 1) leaf[i] = 1;

  int root = 0;
  while (leaf[root] > 0) root++;
  dfs(root, -1);
  total_leafs = leaf[root];

  while (!test(root)) root++;

  for (auto y : g[root]) {
    vi group;
    dfs2(y, root, group);
    groups.pb(group);
  }


  priority_queue<pair<int,int>> pq;
  int I = 0;
  for (auto & gr : groups) {
    pq.push({gr.size(), I});
    I++;
  }
  vector<pair<int,int>> ans;

  while (true) {
    pair<int,int> a = pq.top(); pq.pop();
    pair<int,int> b = pq.top(); pq.pop();

    if (a.first == 0) break;
    if (b.first == 0) {
      ans.pb({groups[a.second][0], root});
      break;
    }
    ans.pb({groups[a.second][a.first-1], groups[b.second][b.first-1]});
    pq.push({a.first-1, a.second});
    pq.push({b.first-1, b.second});
  }

  cout << ans.size() << endl;
  for (auto [a, b] : ans) {
    cout << a + 1 << " " << b + 1 << endl;
  }

}

Compilation message

net.cpp: In function 'int main()':
net.cpp:106:13: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  106 |   for (auto [a, b] : ans) {
      |             ^

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 1 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 0 ms 212 KB Output is correct
10 Correct 1 ms 212 KB Output is correct
11 Correct 0 ms 212 KB Output is correct
12 Correct 1 ms 212 KB Output is correct
13 Correct 0 ms 212 KB Output is correct
14 Correct 0 ms 212 KB Output is correct
15 Correct 1 ms 212 KB Output is correct
16 Correct 0 ms 212 KB Output is correct
17 Correct 0 ms 212 KB Output is correct
18 Correct 0 ms 212 KB Output is correct
19 Correct 1 ms 212 KB Output is correct
20 Correct 1 ms 212 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 1 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 0 ms 212 KB Output is correct
10 Correct 1 ms 212 KB Output is correct
11 Correct 0 ms 212 KB Output is correct
12 Correct 1 ms 212 KB Output is correct
13 Correct 0 ms 212 KB Output is correct
14 Correct 0 ms 212 KB Output is correct
15 Correct 1 ms 212 KB Output is correct
16 Correct 0 ms 212 KB Output is correct
17 Correct 0 ms 212 KB Output is correct
18 Correct 0 ms 212 KB Output is correct
19 Correct 1 ms 212 KB Output is correct
20 Correct 1 ms 212 KB Output is correct
21 Correct 1 ms 212 KB Output is correct
22 Correct 3 ms 468 KB Output is correct
23 Correct 3 ms 468 KB Output is correct
24 Correct 3 ms 468 KB Output is correct
25 Correct 2 ms 468 KB Output is correct
26 Correct 2 ms 340 KB Output is correct
27 Correct 3 ms 420 KB Output is correct
28 Correct 2 ms 340 KB Output is correct
29 Correct 2 ms 340 KB Output is correct
30 Correct 1 ms 212 KB Output is correct
31 Correct 3 ms 468 KB Output is correct
32 Correct 1 ms 212 KB Output is correct
33 Correct 1 ms 212 KB Output is correct
34 Correct 1 ms 296 KB Output is correct
35 Correct 1 ms 300 KB Output is correct
36 Correct 1 ms 212 KB Output is correct
37 Correct 1 ms 340 KB Output is correct
38 Correct 1 ms 340 KB Output is correct
39 Correct 1 ms 212 KB Output is correct
40 Correct 1 ms 212 KB Output is correct
41 Correct 1 ms 212 KB Output is correct
42 Correct 1 ms 340 KB Output is correct
43 Correct 3 ms 432 KB Output is correct
44 Correct 0 ms 300 KB Output is correct
45 Correct 1 ms 212 KB Output is correct
46 Correct 2 ms 340 KB Output is correct
47 Correct 1 ms 212 KB Output is correct
48 Correct 1 ms 300 KB Output is correct
49 Correct 2 ms 312 KB Output is correct
50 Correct 1 ms 212 KB Output is correct
51 Correct 1 ms 300 KB Output is correct
52 Correct 1 ms 212 KB Output is correct
53 Correct 1 ms 340 KB Output is correct
54 Correct 1 ms 296 KB Output is correct
55 Correct 1 ms 340 KB Output is correct
56 Correct 1 ms 212 KB Output is correct
57 Correct 1 ms 340 KB Output is correct
58 Correct 3 ms 468 KB Output is correct

Subtask #3
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 1 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 0 ms 212 KB Output is correct
10 Correct 1 ms 212 KB Output is correct
11 Correct 0 ms 212 KB Output is correct
12 Correct 1 ms 212 KB Output is correct
13 Correct 0 ms 212 KB Output is correct
14 Correct 0 ms 212 KB Output is correct
15 Correct 1 ms 212 KB Output is correct
16 Correct 0 ms 212 KB Output is correct
17 Correct 0 ms 212 KB Output is correct
18 Correct 0 ms 212 KB Output is correct
19 Correct 1 ms 212 KB Output is correct
20 Correct 1 ms 212 KB Output is correct
21 Correct 1 ms 212 KB Output is correct
22 Correct 3 ms 468 KB Output is correct
23 Correct 3 ms 468 KB Output is correct
24 Correct 3 ms 468 KB Output is correct
25 Correct 2 ms 468 KB Output is correct
26 Correct 2 ms 340 KB Output is correct
27 Correct 3 ms 420 KB Output is correct
28 Correct 2 ms 340 KB Output is correct
29 Correct 2 ms 340 KB Output is correct
30 Correct 1 ms 212 KB Output is correct
31 Correct 3 ms 468 KB Output is correct
32 Correct 1 ms 212 KB Output is correct
33 Correct 1 ms 212 KB Output is correct
34 Correct 1 ms 296 KB Output is correct
35 Correct 1 ms 300 KB Output is correct
36 Correct 1 ms 212 KB Output is correct
37 Correct 1 ms 340 KB Output is correct
38 Correct 1 ms 340 KB Output is correct
39 Correct 1 ms 212 KB Output is correct
40 Correct 1 ms 212 KB Output is correct
41 Correct 1 ms 212 KB Output is correct
42 Correct 1 ms 340 KB Output is correct
43 Correct 3 ms 432 KB Output is correct
44 Correct 0 ms 300 KB Output is correct
45 Correct 1 ms 212 KB Output is correct
46 Correct 2 ms 340 KB Output is correct
47 Correct 1 ms 212 KB Output is correct
48 Correct 1 ms 300 KB Output is correct
49 Correct 2 ms 312 KB Output is correct
50 Correct 1 ms 212 KB Output is correct
51 Correct 1 ms 300 KB Output is correct
52 Correct 1 ms 212 KB Output is correct
53 Correct 1 ms 340 KB Output is correct
54 Correct 1 ms 296 KB Output is correct
55 Correct 1 ms 340 KB Output is correct
56 Correct 1 ms 212 KB Output is correct
57 Correct 1 ms 340 KB Output is correct
58 Correct 3 ms 468 KB Output is correct
59 Correct 762 ms 44212 KB Output is correct
60 Correct 944 ms 38060 KB Output is correct
61 Correct 1 ms 212 KB Output is correct
62 Correct 1 ms 212 KB Output is correct
63 Correct 713 ms 37648 KB Output is correct
64 Correct 5 ms 852 KB Output is correct
65 Correct 20 ms 3056 KB Output is correct
66 Correct 224 ms 22420 KB Output is correct
67 Correct 734 ms 49080 KB Output is correct
68 Correct 748 ms 50024 KB Output is correct
69 Correct 21 ms 2544 KB Output is correct
70 Correct 263 ms 22820 KB Output is correct
71 Correct 878 ms 72916 KB Output is correct
72 Correct 840 ms 69144 KB Output is correct
73 Correct 199 ms 10508 KB Output is correct
74 Correct 802 ms 37484 KB Output is correct
75 Correct 83 ms 6672 KB Output is correct
76 Correct 832 ms 57156 KB Output is correct
77 Correct 833 ms 58276 KB Output is correct
78 Correct 53 ms 5428 KB Output is correct
79 Correct 720 ms 46620 KB Output is correct
80 Correct 7 ms 724 KB Output is correct
81 Correct 250 ms 18852 KB Output is correct
82 Correct 824 ms 54988 KB Output is correct
83 Correct 756 ms 35936 KB Output is correct
84 Correct 807 ms 36012 KB Output is correct
85 Correct 779 ms 35888 KB Output is correct
86 Correct 779 ms 37396 KB Output is correct
87 Correct 825 ms 37508 KB Output is correct