Submission #1234277

#	Time	Username	Problem	Language	Result	Execution time	Memory
1234277		dosts	Radio Towers (IOI22_towers)	C++20	23 / 100	4069 ms	11160 KiB

towers

#include "towers.h"
#include <bits/stdc++.h>
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2")
//#define int long long
#define pii pair<int,int>
#define vi vector<int>
#define ff first
#define ss second
#define sp << " " <<
#define all(x) x.begin(),x.end()
#define big(x) ((int)(x.size()))
using namespace std;
const int MOD = 1e9+7, inf = 2e9,LIM = 2001;

vi h;
int up[100001][18];

int rmq(int l,int r) {
  if (l > r) return -inf;
  int lg = __lg(r-l+1);
  return max(up[l][lg],up[r-(1<<lg)+1][lg]);
}
void init(int N, std::vector<int> H) {
  h = H;
  for (int i = 0;i<N;i++) up[i][0] = H[i];
  for (int i=1;i<=17;i++) {
    for (int j=0;j+(1<<(i-1))<N;j++) up[j][i] = max(up[j][i-1],up[j+(1<<(i-1))][i-1]);
  }
}

int max_towers(int L, int R, int D) {
  int ans = 0;
  vector<pii> ps;
  for (int j=L;j<=R;j++) {
    ps.push_back({h[j],j});
  }
  sort(all(ps));
  set<int> taken;
  for (auto& [v,p] : ps) {
    int fl = 1;
    auto it = taken.upper_bound(p);
    auto it2 = taken.lower_bound(p);
    if (it != taken.end()) {
      int mx = rmq(p+1,*it-1);
      if (mx < h[p]+D || mx < h[*it]+D) fl = 0;
    }
    if (it2 != taken.begin()) {
      --it2;
      int mx = rmq(*it2+1,p-1);
      if (mx < h[p]+D || mx < h[*it2]+D) fl = 0;
    }
    if (fl) {
      ans++;
      taken.insert(p);
    }
  }
  return ans;
}

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