Submission #761469

#	Time	Username	Problem	Language	Result	Execution time	Memory
761469		Sam_a17	Papričice (COCI20_papricice)	C++17	110 / 110	188 ms	29256 KiB

papricice

///
#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
//#include "temp.cpp"
#include <cstdio>
using namespace std;
 
#ifndef ONLINE_JUDGE
#define dbg(x) cerr << #x <<" "; print(x); cerr << endl;
#else
#define dbg(x)
#endif
 
#define sz(x) (int)x.size()
#define len(x) (int)x.length()
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define clr(x) (x).clear()
#define uniq(x) x.resize(unique(all(x)) - x.begin());
#define blt __builtin_popcount
 
#define pb push_back
#define popf pop_front
#define popb pop_back
#define ld long double
 
void print(long long t) {cerr << t;}
void print(int t) {cerr << t;}
void print(string t) {cerr << t;}
void print(char t) {cerr << t;}
void print(double t) {cerr << t;}
void print(long double t) {cerr << t;}
void print(unsigned long long t) {cerr << t;}
 
template <class T, class V> void print(pair <T, V> p);
template <class T> void print(vector <T> v);
template <class T> void print(set <T> v);
template <class T, class V> void print(map <T, V> v);
template <class T> void print(multiset <T> v);
template <class T, class V> void print(T v[],V n) {cerr << "["; for(int i = 0; i < n; i++) {print(v[i]); cerr << " "; } cerr << "]";}
template <class T, class V> void print(pair <T, V> p) {cerr << "{"; print(p.first); cerr << ","; print(p.second); cerr << "}";}
template <class T> void print(vector <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(set <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(multiset <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T, class V> void print(map <T, V> v) {cerr << "[ "; for (auto i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(deque <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
 
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
#define nl '\n'
 
// for random generations
// mt19937 myrand(chrono::steady_clock::now().time_since_epoch().count());
mt19937 myrand(373);
 
// for grid problems
int dx[8] = {-1,0,1,0,1,-1,1,-1};
int dy[8] = {0,1,0,-1,1,1,-1,-1};
 
// lowest / (1 << 17) >= 1e5 / (1 << 18) >= 2e5 / (1 << 21) >= 1e6
void fastIO() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr); cout.tie(nullptr);
}
// file in/out
void setIO(string str = "") {
  fastIO();
 
  if(str == "input") {
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
  } else {
    // freopen("skis.in", "r", stdin);
    // freopen("skis.out", "w", stdout);
  }
}
// Indexed Set  
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
const int N = 2e5 + 10;
vector<pair<int, int>> adj[N];
int n, sz[N], cur_edge, ans;
bool vis[N];

multiset<int> up, not_up;

void dfs_sz(int node, int parent) {
  sz[node] = 1;
  for(auto i: adj[node]) {
    if(i.first == parent) continue;
    dfs_sz(i.first, node);
    sz[node] += sz[i.first];
  }
}

void relax(int a, int b, int c) {
  ans = min(ans, max({a, b, c}) - min({a, b, c}));
}

void dfs(int node, int parent) {
  if(node != 1) {
    // up case
    int other = n - sz[node];
    auto it = up.lower_bound(other / 2 + sz[node]);
    if(it != up.end()) {
      int cur = *it - sz[node];
      relax(sz[node], cur, n - cur - sz[node]);
    }

    if(it != up.begin()) {
      it = prev(it);
      int cur = *it - sz[node];
      relax(sz[node], cur, n - cur - sz[node]);
    }

    // not_up case
    if(!not_up.empty()) {
      other = n - sz[node];
      it = not_up.lower_bound(other / 2);
      if(it != not_up.end()) {
        int cur = *it;
        relax(sz[node], cur, n - cur - sz[node]);
      }

      if(it != not_up.begin()) {
        it = prev(it);
        int cur = *it;
        relax(sz[node], cur, n - cur - sz[node]);
      }
    }
  }

  up.insert(sz[node]);
  for(auto i: adj[node]) {
    if(i.first == parent) continue;
    dfs(i.first, node); 
  }

  up.erase(up.find(sz[node]));
  not_up.insert(sz[node]);
}

void solve_() {
  cin >> n, ans = n;
  
  for(int i = 1; i <= n - 1; i++) {
    int a, b; cin >> a >> b;
    adj[a].push_back({b, i});
    adj[b].push_back({a, i});
  }

  dfs_sz(1, 0);

  dfs(1, 0);
  
  cout << ans << '\n';
}
 
int main() {
  setIO();
 
  auto solve = [&](int test_case)-> void {
    for(int i = 1; i <= test_case; i++) {
      solve_();
    }
  };
 
  int test_cases = 1;
  // cin >> test_cases;
  solve(test_cases);
 
  return 0;
} 

Compilation message (stderr)

papricice.cpp: In function 'void setIO(std::string)':
papricice.cpp:70:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   70 |     freopen("input.txt", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
papricice.cpp:71:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   71 |     freopen("output.txt", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 15 / 15
• Subtask 2: 35 / 35
• Subtask 3: 60 / 60