Submission #790826

#	Time	Username	Problem	Language	Result	Execution time	Memory
790826		penguinman	Radio Towers (IOI22_towers)	C++17	23 / 100	4014 ms	2688 KiB

towers

#include "towers.h"

#include <bits/stdc++.h>

using std::vector;
using std::string;
using std::cin;
using std::cout;
using ll = int;
using vi = vector<ll>;
using vii = vector<vi>;
using pii = std::pair<ll,ll>;
#define ln "\n"
#define rep(i,j,k) for(ll i=ll(j); i<ll(k); i++)
#define REP(i,j,k) for(ll i=ll(j); i<=ll(k); i++)
#define per(i,j,k) for(ll i=ll(j); i>=ll(k); i--)
#define all(a) a.begin(), a.end()
#define mp std::make_pair
#define pb emplace_back
constexpr ll inf = (1<<30)+(1<<29)+(1<<28);

ll N;
vi H;
ll D;
vi right, left;
constexpr ll di = 20;
ll sz;
vii pr, mr, pl, ml;
vii sum;

void init(int n, std::vector<int> h) {
  N = n;
  H.resize(N);
  right.resize(N);
  left.resize(N);
  rep(i,0,N) H[i] = h[i];
  D = -1;
}

int max_towers(int L, int R, int d) {
  if(D == -1){
    D = d;
    {
      sz = N/di+10;
      /*
      sum.resize(sz, vi(sz));
      pr.resize(N+2);
      mr.resize(N+2);
      pl.resize(N+2);
      ml.resize(N+2);*/
      std::deque<ll> ima, vma, imi, vmi;
      ima.pb(-3);
      vma.pb(-inf);
      imi.pb(-2);
      vmi.pb(inf);
      rep(i,0,N){
        ll large = lower_bound(all(vmi), H[i]+D)-vmi.begin();
        large = imi[large];
        ll small = lower_bound(all(vma),H[i])-vma.begin()-1;
        small = ima[small];
        if(small >= large) left[i] = small+1;
        else left[i] = -1;
        while(true){
          if(vma[vma.size()-1] > H[i]) vma.pop_back(), ima.pop_back();
          else break;
        }
        vma.pb(H[i]);
        ima.pb(i);
        while(true){
          if(vmi[0] < H[i]) vmi.pop_front(), imi.pop_front();
          else break;
        }
        vmi.emplace_front(H[i]);
        imi.emplace_front(i);
      }
    }
    {
      std::deque<ll> ima, vma, imi, vmi;
      ima.pb(N+3);
      vma.pb(-inf);
      imi.pb(N+2);
      vmi.pb(inf);
      per(i,N-1,0){
        ll large = lower_bound(all(vmi), H[i]+D)-vmi.begin();
        large = imi[large];
        ll small = lower_bound(all(vma),H[i])-vma.begin()-1;
        small = ima[small];
        if(small <= large) right[i] = small-1;
        else right[i] = N;
        while(true){
          if(vma[vma.size()-1] > H[i]) vma.pop_back(), ima.pop_back();
          else break;
        }
        vma.pb(H[i]);
        ima.pb(i);
        while(true){
          if(vmi[0] < H[i]) vmi.pop_front(), imi.pop_front();
          else break;
        }
        vmi.emplace_front(H[i]);
        imi.emplace_front(i);
      }
    }
    /*
    rep(i,0,N){
      left[i]++;
      right[i]++;
      ll ld = (left[i]+di-1)/di;
      ll rd = right[i]/di;
      sum[ld][rd]++;
      ll id = i/di;
      sum[ld][id]--;
      id = (i+di-1)/di;
      sum[id][rd]--;
      pr[right[i]].pb(left[i]);
      pl[left[i]].pb(right[i]);
      ml[i+1].pb(right[i]);
      ml[left[i]].pb(i+1);
      mr[i+1].pb(left[i]);
      mr[right[i]].pb(i+1);
    }
    REP(l,1,sz){
      rep(i,0,sz){
        ll j = i+l;
        if(j >= sz) break;
        sum[i][j] = sum[i+1][j]+sum[i][j-1]-sum[i+1][j-1];
      }
    }*/
  }
  ll ans = 0;
  ll ld = (L+di-1)/di;
  ll rd = R/di;
  //ans = psum[ld][rd]-msum[ld][rd];
  ans = 0;
  rep(i,0,N){
    if(left[i] <= L && R <= right[i]) ans++;
  }
  rep(i,0,L){
    if(R <= right[i]) ans--;
  }
  rep(i,R+1,N){
    if(left[i] <= L) ans--;
  }
  return ans;
}

Compilation message (stderr)

towers.cpp: In function 'int max_towers(int, int, int)':
towers.cpp:131:6: warning: unused variable 'ld' [-Wunused-variable]
  131 |   ll ld = (L+di-1)/di;
      |      ^~
towers.cpp:132:6: warning: unused variable 'rd' [-Wunused-variable]
  132 |   ll rd = R/di;
      |      ^~

• 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