Submission #1245106

#	Time	Username	Problem	Language	Result	Execution time	Memory
1245106		guanex	Radio Towers (IOI22_towers)	C++20	23 / 100	4097 ms	32532 KiB

towers

#include "towers.h"

#include <vector>

#include<bits/stdc++.h>

using namespace std;

vector<int> h;
pair<int, int> st[500005][20];
int stt[500005][20];

void init(int N, std::vector<int> H) {
  int mx = 0;
  for(int i = 0; i < N; ++i){
    st[i][0] = {H[i], i};
    stt[i][0] = H[i];
    h.push_back(H[i]);
  }
  for(int bit = 1; bit <= 18; ++bit){
    //cout << bit << endl;s
    for(int i = 0; i < N; ++i){
      st[i][bit] = max(st[i][bit-1], st[i + (1 << (bit-1))][bit-1]);
      stt[i][bit] = min(stt[i][bit-1], stt[i + (1 << (bit-1))][bit-1]);
    }
  }
}

int solve(int l, int r, int d, int lim){
  if(r < l){
    return 0;
  }
  if(l == r){
    if(h[l] <= lim){
      return 1;
    }else{
      return 0;
    }
  }
  int dist = log2(r - l + 1);
  int mid = st[l][dist].second;
  int mn = min(stt[l][dist], stt[r - (1 << dist) + 1][dist]);
  if(st[r - (1 << dist) + 1][dist].first > st[l][dist].first){
    mid = st[r - (1 << dist) + 1][dist].second;
  }
  //cout << l << " " << r << " " << mid << endl;
  return max((mn <= lim)?1:0, solve(l, mid-1, d, h[mid] - d) + solve(mid+1, r, d, h[mid] - d));
}

int max_towers(int L, int R, int D) {
  return solve(L, R, D, 1000000001);
}

• 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