Submission #1063502

#	Time	Username	Problem	Language	Result	Execution time	Memory
1063502		MarwenElarbi	Radio Towers (IOI22_towers)	C++17	0 / 100	441 ms	4048 KiB

towers

#include <bits/stdc++.h>
using namespace std;
#include "towers.h"
#define pb push_back
#define ll long long
#define fi first
#define se second
const int nax=1e5+5;
int lefty[nax],righty[nax];
int segtree[nax*4];
int n;
vector<int> tab;
int pre[nax];
vector<int> ans;
void build(int pos,int l,int r){
  if(l==r){
    segtree[pos]=tab[l];
    return;
  }
  int mid=(r+l)/2;
  build(pos*2+1,l,mid);
  build(pos*2+2,mid+1,r);
  segtree[pos]=max(segtree[pos*2+1],segtree[pos*2+2]);
  return;
}
int query(int pos,int l,int r,int left,int right){
  if(l>r||l>right||r<left) return -1;
  if(l>=left&&r<=right) return segtree[pos];
  int mid=(r+l)/2;
  return max(query(pos*2+1,l,mid,left,right),query(pos*2+2,mid+1,r,left,right));
}
void init(int N, std::vector<int> H) {
  n=N;
  for (int i = 0; i < N; ++i)
  {
    tab.pb(H[i]);
  }
  stack<pair<int,int>> st;
  for (int i = 0; i < n; ++i)
  {
    while(!st.empty()){
      if(st.top().fi>tab[i]){
        st.pop();
      }else break;
    }
    lefty[i]=(!st.empty() ? st.top().se : -1);
    st.push({tab[i],i});
  }
  while(!st.empty()) st.pop();
  for (int i = n-1; i >= 0; --i)
  {
    while(!st.empty()){
      if(st.top().fi>tab[i]){
        st.pop();
      }else break;
    }
    righty[i]=(!st.empty() ? st.top().se : n);
    st.push({tab[i],i});
  }
  build(0,0,n-1);
  for (int i = 0; i < n; ++i)
  {
    int a=query(0,0,n-1,lefty[i]+1,i-1);
    int b=query(0,0,n-1,i+1,righty[i]-1);
    if(a==-1) a=2e9;
    if(b==-1) b=2e9;
    ans.pb(min(a,b)-tab[i]);
  }
  sort(ans.begin(),ans.end());
}

int max_towers(int L, int R, int D){
  int l=-1;
  int r=n;
  while(r-l>1){
    int mid=(r+l)/2;
    if(ans[mid]<=D) l=mid;
    else r=mid;
  }
  return max(l+1,1);
}

• 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