Submission #1057078

#	Time	Username	Problem	Language	Result	Execution time	Memory
1057078		mychecksedad	Radio Towers (IOI22_towers)	C++17	0 / 100	628 ms	12860 KiB

towers

#include "towers.h"
#include<bits/stdc++.h>
using namespace std;
#define pb push_back
#define all(x) x.begin(),x.end()
#define ll long long int
#define en cout << '\n'
#define pii pair<int,int>
#define vi vector<int> 
#define ff first
#define ss second

struct Fenwick{
  vector<int> t;
  int n;
  Fenwick(int n): n(n){
    t.resize(n+1);
  }
  void add(int v){
    while(v <= n){
      t[v]++;
      v += v&-v;
    }
  }
  int get(int v){
    int res = 0;
    while(v > 0){
      res += t[v];
      v -= v&-v;
    }
    return res;
  }
};


void op(vector<int> &a, vector<int> &A, vector<int> &B){
  if(a.size() <= 1){
    A = a;
    B.pb(0);
    return;
  }
  A.pb(a[0]);
  A.pb(a[1]);
  B.pb(0);
  B.pb(1);
  for(int i = 2; i < a.size(); ++i){
    if(a[i] > A.back() && A.back() > A[int(A.size()) - 2]){
      A.pop_back();
      B.pop_back();
      A.pb(a[i]);
      B.pb(i);
    }else if(a[i] < A.back() && A.back() < A[int(A.size()) - 2]){
      A.pop_back();
      B.pop_back();
      A.pb(a[i]);
      B.pb(i);
    }else{
      A.pb(a[i]);
      B.pb(i);
    }
  }
  
}
int n;
vector<int> A, B, A2, A1, B1, B2, a;
Fenwick f(1000000);

  vector<pair<int, int>> ans;
void init(int nn, std::vector<int> aa) { n=nn;a=aa;
  if(n == 1) return;
  op(a, A, B);


  if(A[0] > A[1]) A.erase(A.begin());
  if(A.size()==1) return;
  if(A.back() > A[A.size() - 2]) A.pop_back();
  if(A.size()==1) return;

  set<pair<int,int>> S;
  priority_queue<array<int, 3>> Q;

  int m = A.size();
  for(int i = 0; i < m; ++i){
    S.insert({i, A[i]});
    if(i + 1 < m && A[i + 1] > A[i]) Q.push({-(A[i + 1] - A[i]), i, i + 1});
    if(i > 0 && A[i - 1] > A[i]) Q.push({-(A[i - 1] - A[i]), i, i - 1});
  }
  ans.pb({1, A.size() / 2 + 1});
  vector<bool> rem(A.size());
  while(!Q.empty()){
    auto V = Q.top();
    int v = V[1], u = V[2];
    int val = V[0];
    Q.pop();
    if(rem[u] || rem[v]) continue;
    S.erase({v, A[v]});
    S.erase({u, A[u]});
    rem[u] = rem[v] = 1;
    int mx = max(u, v);
    auto it = S.lower_bound(pair<int,int>{mx, -1});
    if(it != S.begin() && it != S.end()){
      auto it2 = prev(it);
      auto x = *it;
      auto y = *it2;
      Q.push({-abs(x.ss - y.ss), x.ff, y.ff});
    }
    assert(S.size()%2);
    if(ans.back().ff == -val){
      ans.back().ss = S.size() / 2 + 1;
    }else ans.pb({-val, S.size() / 2 + 1});
  }

}

int max_towers(int L, int R, int D) { ++L, ++R;
  if(n == 1 || L == R || A.size() == 1) return 1;
  int pos = upper_bound(all(ans), pii{D, -1}) - ans.begin() - 1;
  return max(pos == ans.size() ? 1 : ans[pos].ss, 1);
}

Compilation message (stderr)

towers.cpp: In function 'void op(std::vector<int>&, std::vector<int>&, std::vector<int>&)':
towers.cpp:46:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   46 |   for(int i = 2; i < a.size(); ++i){
      |                  ~~^~~~~~~~~~
towers.cpp: In function 'int max_towers(int, int, int)':
towers.cpp:118:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  118 |   return max(pos == ans.size() ? 1 : ans[pos].ss, 1);
      |              ~~~~^~~~~~~~~~~~~

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