oj.uz

Submission #931682

# Submission time Handle Problem Language Result Execution time Memory
931682 2024-02-22T09:06:38 Z vjudge1 Network (BOI15_net) C++17
100 / 100
 488 ms 89136 KB 
/// ITNOG
#include <bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
//#pragma GCC optimize("O3,unroll-loops")
//#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#define F first
#define S second
#define pb push_back
#define ppb pop_back
#define fast_io ios::sync_with_stdio(false);cin.tie(NULL);
#define file_io freopen("input.txt","r",stdin);freopen("output.txt","w",stdout);
#define FOR(i,k,n) for(int i = k; i < n; ++ i)
#define debf cout<<"(0-0)\n";
#define all(x) x.begin(), x.end()
#define dec(x) cout << fixed << setprecision(x);
#define pf push_front
#define ppf pop_front
#define dash " ------- "
#define what(x) cerr << #x << " is " << x << endl;
#define eb emplace_back
//#define int short int
#define int long long
#define sz(s) (int) (s.size())
#define fl cout.flush()

using namespace std;
//using namespace __gnu_pbds;

typedef long long ll;
typedef pair <int, int> pii;
typedef pair <int, pii> pip;
typedef pair <pii, int> ppi;
typedef pair <ll, ll> pll;
typedef unsigned long long ull;
typedef long double ld;

template <class T> using max_heap = priority_queue <T, vector <T>, less <T> >;
template <class T> using min_heap = priority_queue <T, vector <T>, greater <T> >;
//template <class T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

constexpr int MOD = 1e9 + 7, N = 5e5 + 8, M = 1e6, SQ = 600, INF = 1e15 + 8, LGN = 22, mod = 998244353, P = 131113;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

int n, leaf, subleaf[N], r1;
vector <int> adj[N];
vector <int> v[N];
vector <pii> ans;
max_heap <pii> pq;

void dfs (int u, int par = -1){
  if (adj[u].size() == 1){
    ++ leaf;
    ++ subleaf[u];
  }
  for (int i : adj[u]){
    if (i != par){
      dfs (i, u);
      subleaf[u] += subleaf[i];
    }
  }
  return;
}

void dfs2 (int u, int par = -1){
  for (int i = 0; i < adj[u].size(); ++ i){
    int x = adj[u][i];
    if (x != par){
      if (subleaf[x] > leaf / 2){
        i = INF;
        r1 = x;
        dfs2 (x, u);
      }
    }
  }
  return;
}

void dfs3 (int u, int xx = -1, int par = -1){
  if (adj[u].size() == 1){
    v[xx].pb(u);
  }
  for (int i : adj[u]){
    if (i != par){
      if (u == r1){
        dfs3 (i, i, u);
      }
      else {
        dfs3 (i, xx, u);
      }
    }
  }
  return;
}

int32_t main(){
  fast_io;
  cin >> n;
  FOR (i, 0, n - 1){
    int aa, bb;
    cin >> aa >> bb;
    adj[--aa].pb(--bb);
    adj[bb].pb(aa);
    if (adj[aa].size() > 1){
      r1 = aa;
    }
  }
  dfs (r1);
  dfs2 (r1);
  cout << (leaf + 1) / 2 << '\n';
  dfs3 (r1);
  for (int i = 0; i < n; ++ i){
    if (v[i].size()){
      pq.push({v[i].size(), i});
    }
  }
  while (pq.size()){
    if (pq.size() == 1){
      break;
    }
    pii p1 = pq.top();
    pq.pop();
    pii p2 = pq.top();
    pq.pop();
    ans.pb({v[p1.S].back(), v[p2.S].back()});
    v[p1.S].ppb();
    v[p2.S].ppb();
    -- p1.F;
    -- p2.F;
    if (p1.F){
      pq.push(p1);
    }
    if (p2.F){
      pq.push(p2);
    }
  }
  if (pq.size() == 1){
    ans.pb({v[pq.top().S].back(), r1});
  }
  for (pii i : ans){
    cout << i.F + 1 << " " << i.S + 1 << '\n';
  }
  return 0;
}

// Yesterday is history
// Tomorrow is a mystery
// but today is a gift
// That is why it is called the present

Compilation message

net.cpp: In function 'void dfs2(long long int, long long int)':
net.cpp:67:21: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   67 |   for (int i = 0; i < adj[u].size(); ++ i){
      |                   ~~^~~~~~~~~~~~~~~

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 25176 KB Output is correct
2 Correct 5 ms 25180 KB Output is correct
3 Correct 5 ms 25220 KB Output is correct
4 Correct 5 ms 25180 KB Output is correct
5 Correct 5 ms 25176 KB Output is correct
6 Correct 5 ms 25180 KB Output is correct
7 Correct 6 ms 25180 KB Output is correct
8 Correct 6 ms 25180 KB Output is correct
9 Correct 5 ms 25180 KB Output is correct
10 Correct 6 ms 25180 KB Output is correct
11 Correct 6 ms 25176 KB Output is correct
12 Correct 5 ms 25180 KB Output is correct
13 Correct 6 ms 25180 KB Output is correct
14 Correct 5 ms 25180 KB Output is correct
15 Correct 6 ms 25180 KB Output is correct
16 Correct 5 ms 25180 KB Output is correct
17 Correct 5 ms 25176 KB Output is correct
18 Correct 6 ms 25180 KB Output is correct
19 Correct 5 ms 25180 KB Output is correct
20 Correct 5 ms 25180 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 25176 KB Output is correct
2 Correct 5 ms 25180 KB Output is correct
3 Correct 5 ms 25220 KB Output is correct
4 Correct 5 ms 25180 KB Output is correct
5 Correct 5 ms 25176 KB Output is correct
6 Correct 5 ms 25180 KB Output is correct
7 Correct 6 ms 25180 KB Output is correct
8 Correct 6 ms 25180 KB Output is correct
9 Correct 5 ms 25180 KB Output is correct
10 Correct 6 ms 25180 KB Output is correct
11 Correct 6 ms 25176 KB Output is correct
12 Correct 5 ms 25180 KB Output is correct
13 Correct 6 ms 25180 KB Output is correct
14 Correct 5 ms 25180 KB Output is correct
15 Correct 6 ms 25180 KB Output is correct
16 Correct 5 ms 25180 KB Output is correct
17 Correct 5 ms 25176 KB Output is correct
18 Correct 6 ms 25180 KB Output is correct
19 Correct 5 ms 25180 KB Output is correct
20 Correct 5 ms 25180 KB Output is correct
21 Correct 5 ms 25180 KB Output is correct
22 Correct 6 ms 25436 KB Output is correct
23 Correct 7 ms 25436 KB Output is correct
24 Correct 6 ms 25436 KB Output is correct
25 Correct 6 ms 25176 KB Output is correct
26 Correct 6 ms 25180 KB Output is correct
27 Correct 6 ms 25180 KB Output is correct
28 Correct 6 ms 25180 KB Output is correct
29 Correct 6 ms 25276 KB Output is correct
30 Correct 5 ms 25176 KB Output is correct
31 Correct 6 ms 25180 KB Output is correct
32 Correct 6 ms 25044 KB Output is correct
33 Correct 5 ms 25192 KB Output is correct
34 Correct 7 ms 25184 KB Output is correct
35 Correct 7 ms 25180 KB Output is correct
36 Correct 5 ms 25180 KB Output is correct
37 Correct 6 ms 25180 KB Output is correct
38 Correct 6 ms 25176 KB Output is correct
39 Correct 6 ms 25180 KB Output is correct
40 Correct 6 ms 25180 KB Output is correct
41 Correct 6 ms 25096 KB Output is correct
42 Correct 6 ms 25180 KB Output is correct
43 Correct 6 ms 25176 KB Output is correct
44 Correct 6 ms 25180 KB Output is correct
45 Correct 5 ms 25180 KB Output is correct
46 Correct 6 ms 25180 KB Output is correct
47 Correct 6 ms 25180 KB Output is correct
48 Correct 6 ms 25180 KB Output is correct
49 Correct 6 ms 25180 KB Output is correct
50 Correct 6 ms 25176 KB Output is correct
51 Correct 6 ms 25176 KB Output is correct
52 Correct 6 ms 25180 KB Output is correct
53 Correct 6 ms 25296 KB Output is correct
54 Correct 5 ms 25260 KB Output is correct
55 Correct 6 ms 25180 KB Output is correct
56 Correct 5 ms 25180 KB Output is correct
57 Correct 5 ms 25180 KB Output is correct
58 Correct 6 ms 25180 KB Output is correct

Subtask #3
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 25176 KB Output is correct
2 Correct 5 ms 25180 KB Output is correct
3 Correct 5 ms 25220 KB Output is correct
4 Correct 5 ms 25180 KB Output is correct
5 Correct 5 ms 25176 KB Output is correct
6 Correct 5 ms 25180 KB Output is correct
7 Correct 6 ms 25180 KB Output is correct
8 Correct 6 ms 25180 KB Output is correct
9 Correct 5 ms 25180 KB Output is correct
10 Correct 6 ms 25180 KB Output is correct
11 Correct 6 ms 25176 KB Output is correct
12 Correct 5 ms 25180 KB Output is correct
13 Correct 6 ms 25180 KB Output is correct
14 Correct 5 ms 25180 KB Output is correct
15 Correct 6 ms 25180 KB Output is correct
16 Correct 5 ms 25180 KB Output is correct
17 Correct 5 ms 25176 KB Output is correct
18 Correct 6 ms 25180 KB Output is correct
19 Correct 5 ms 25180 KB Output is correct
20 Correct 5 ms 25180 KB Output is correct
21 Correct 5 ms 25180 KB Output is correct
22 Correct 6 ms 25436 KB Output is correct
23 Correct 7 ms 25436 KB Output is correct
24 Correct 6 ms 25436 KB Output is correct
25 Correct 6 ms 25176 KB Output is correct
26 Correct 6 ms 25180 KB Output is correct
27 Correct 6 ms 25180 KB Output is correct
28 Correct 6 ms 25180 KB Output is correct
29 Correct 6 ms 25276 KB Output is correct
30 Correct 5 ms 25176 KB Output is correct
31 Correct 6 ms 25180 KB Output is correct
32 Correct 6 ms 25044 KB Output is correct
33 Correct 5 ms 25192 KB Output is correct
34 Correct 7 ms 25184 KB Output is correct
35 Correct 7 ms 25180 KB Output is correct
36 Correct 5 ms 25180 KB Output is correct
37 Correct 6 ms 25180 KB Output is correct
38 Correct 6 ms 25176 KB Output is correct
39 Correct 6 ms 25180 KB Output is correct
40 Correct 6 ms 25180 KB Output is correct
41 Correct 6 ms 25096 KB Output is correct
42 Correct 6 ms 25180 KB Output is correct
43 Correct 6 ms 25176 KB Output is correct
44 Correct 6 ms 25180 KB Output is correct
45 Correct 5 ms 25180 KB Output is correct
46 Correct 6 ms 25180 KB Output is correct
47 Correct 6 ms 25180 KB Output is correct
48 Correct 6 ms 25180 KB Output is correct
49 Correct 6 ms 25180 KB Output is correct
50 Correct 6 ms 25176 KB Output is correct
51 Correct 6 ms 25176 KB Output is correct
52 Correct 6 ms 25180 KB Output is correct
53 Correct 6 ms 25296 KB Output is correct
54 Correct 5 ms 25260 KB Output is correct
55 Correct 6 ms 25180 KB Output is correct
56 Correct 5 ms 25180 KB Output is correct
57 Correct 5 ms 25180 KB Output is correct
58 Correct 6 ms 25180 KB Output is correct
59 Correct 353 ms 64776 KB Output is correct
60 Correct 354 ms 63932 KB Output is correct
61 Correct 5 ms 25180 KB Output is correct
62 Correct 5 ms 25020 KB Output is correct
63 Correct 303 ms 58500 KB Output is correct
64 Correct 6 ms 25436 KB Output is correct
65 Correct 13 ms 27228 KB Output is correct
66 Correct 114 ms 42836 KB Output is correct
67 Correct 485 ms 80484 KB Output is correct
68 Correct 472 ms 68048 KB Output is correct
69 Correct 12 ms 26844 KB Output is correct
70 Correct 89 ms 44988 KB Output is correct
71 Correct 380 ms 89136 KB Output is correct
72 Correct 389 ms 86556 KB Output is correct
73 Correct 56 ms 33788 KB Output is correct
74 Correct 350 ms 59392 KB Output is correct
75 Correct 30 ms 30292 KB Output is correct
76 Correct 349 ms 74268 KB Output is correct
77 Correct 335 ms 75640 KB Output is correct
78 Correct 27 ms 29264 KB Output is correct
79 Correct 488 ms 69500 KB Output is correct
80 Correct 7 ms 25432 KB Output is correct
81 Correct 95 ms 42920 KB Output is correct
82 Correct 403 ms 72968 KB Output is correct
83 Correct 370 ms 59248 KB Output is correct
84 Correct 365 ms 60056 KB Output is correct
85 Correct 358 ms 60092 KB Output is correct
86 Correct 348 ms 63928 KB Output is correct
87 Correct 353 ms 63848 KB Output is correct