Submission #825015

#	Time	Username	Problem	Language	Result	Execution time	Memory
825015		LittleCube	Radio Towers (IOI22_towers)	C++17	17 / 100	651 ms	5784 KiB

towers

#include "towers.h"
#include <bits/stdc++.h>
#define ll long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define F first
#define S second
using namespace std;

namespace
{
  int N;
  vector<int> H, p, l, r, vis;
  map<int, int> mp;
}

void init(int _N, vector<int> _H)
{
  N = _N;
  H = _H;
  H.emplace_back(2e9);

  p = vector<int>(N + 1, 0);
  vector<int> l = p, r = p, vis = p;
  vector<int> mono = {N};

  for (int i = 0; i <= N; i++)
  {
    while (H[mono.back()] < H[i])
      r[mono.back()] = i, mono.pop_back();
    l[i] = mono.back();
    mono.push_back(i);
  }

  for (int i = 0; i < N; i++)
    if (H[l[i]] < H[r[i]])
      p[i] = l[i];
    else
      p[i] = r[i];
  p[N] = N + 1;
  vector<int> v;
  for (int i = 0; i < N; i++)
    vis[p[i]] = 1;
  for (int i = 0; i < N; i++)
    if (!vis[i])
      v.emplace_back(i);
  sort(v.begin(), v.end(), [&](int i, int j)
       { return H[i] < H[j]; });
  
  for (int i = 0; i <= N; i++)
    vis[i] = 0;
  vector<int> inc;
  for (auto i : v)
  {
    int c = i, D = 0;
    while (c != N + 1)
    {
      D = H[c] - H[i];
      if(vis[c])
        break;
      vis[c] = 1;
      c = p[c];
    }
    inc.emplace_back(D);
  }
  sort(inc.begin(), inc.end(), greater<>());
  int acc = 0;
  for (auto i : inc)
  {
    acc++;
    mp[i] = acc;
  }
}

int max_towers(int L, int R, int D)
{
  return mp.lower_bound(D)->second;
}

• Subtask 1: 0 / 4
• Subtask 2: 0 / 11
• Subtask 3: 0 / 12
• Subtask 4: 0 / 14
• Subtask 5: 17 / 17
• Subtask 6: 0 / 19
• Subtask 7: 0 / 23