제출 #964850

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
964850		TAhmed33	통행료 (IOI18_highway)	C++17	18 / 100	124 ms	16300 KiB

highway

#include "highway.h"
//#include "grader.cpp"
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MAXN = 1e5 + 25;
mt19937 rng (chrono::steady_clock::now().time_since_epoch().count());
int random (int l, int r) {
  return uniform_int_distribution <int> (l, r) (rng);
}
vector <pair <int, int>> adj[MAXN];
vector <int> ett, ett2;
int in[MAXN], out[MAXN], dep[MAXN], tt;
void dfs (int pos, int par) {
  in[pos] = ++tt; 
  for (auto j : adj[pos]) {
    if (j.first == par) continue;
    ett.push_back(j.second);
    dep[j.first] = 1 + dep[pos];
    dfs(j.first, pos);
  }
  out[pos] = tt;
}
void dfs2 (int pos) {
  for (auto j : adj[pos]) {
    if (in[j.first] < in[pos]) continue;
    ett2.push_back(j.second);
    dfs2(j.first);
  }
}
void find_pair (int n, vector <int> u, vector <int> v, int a, int b) {
  for (int i = 0; i + 1 < n; i++) {
    adj[u[i]].push_back({v[i], i});
    adj[v[i]].push_back({u[i], i});
  }
  vector <int> g(n - 1);
  ll U = ask(g);
  dfs(0, -1);
  for (int i = 0; i < n - 1; i++) {
    if (dep[u[i]] > dep[v[i]]) swap(u[i], v[i]);
  }
  int l = 0, r = n - 2, p1 = -1;
  while (l <= r) {
    int mid = (l + r) / 2;
    g.clear(); g.resize(n - 1);
    for (int j = 0; j <= mid; j++) g[ett[j]] = 1;
    ll V = ask(g);
    if (V != U) {
      r = mid - 1; p1 = mid;
    } else {
      l = mid + 1;
    }
  }
  l = 0, r = n - 2; int p2 = -1;
  while (l <= r) {
    int mid = (l + r) / 2;
    g.clear(); g.resize(n - 1);
    for (int j = mid; j + 1 < n; j++) g[ett[j]] = 1;
    ll V = ask(g);
    if (V != U) {
      l = mid + 1; p2 = mid;
    } else {
      r = mid - 1;
    }
  }
  p1 = ett[p1]; p2 = ett[p2];
  if (in[u[p1]] <= in[v[p2]] && out[v[p2]] <= out[u[p1]]) {
    answer(u[p1], v[p2]);
    return;
  }
  U /= a; 
  dfs2(v[p1]);
  l = 0, r = (int)ett2.size() - 1; int ans = -1;
  while (l <= r) {
    int mid = (l + r) / 2;
    g.clear(); g.resize(n - 1);
    for (int i = mid; i < (int)ett2.size() - 1; i++) {
      g[ett2[i]] = 1;
    }
    ll V = ask(g);
    if (V != U) {
      l = mid + 1; ans = mid;
    } else {
      r = mid - 1;
    }
  }
  answer(v[ans], v[p2]);
}

• Subtask 1: 5 / 5
• Subtask 2: 7 / 7
• Subtask 3: 6 / 6
• Subtask 4: 0 / 33
• Subtask 5: 0 / 18
• Subtask 6: 0 / 31