Submission #1035084

#	Time	Username	Problem	Language	Result	Execution time	Memory
1035084		irmuun	Radio Towers (IOI22_towers)	C++17	0 / 100	4030 ms	4556 KiB

towers

#include<bits/stdc++.h>
#include "towers.h"

using namespace std;

#define ll long long
#define pb push_back
#define ff first
#define ss second
#define all(s) s.begin(),s.end()
#define rall(s) s.rbegin(),s.rend()

struct segtree{
    vector<int>u,d;
    void init(int n,vector<int>h){
        u=h;
        d.resize(4*n);
        build(1,0,n-1);
    }
    void build(int v,int l,int r){
        if(l==r){
            d[v]=u[l];
            return;
        }
        int mid=(l+r)>>1;
        build(v*2,l,mid);
        build(v*2,mid+1,r);
    }
    int query(int v,int l,int r,int L,int R){
        if(R<L||r<L||R<l) return 0;
        if(L<=l&&r<=R){
            return d[v];
        }
        int mid=(l+r)>>1;
        return max(query(v*2,l,mid,L,R),query(v*2+1,mid+1,r,L,R));
    }
};

segtree sg;

int n;
vector<int>h;
vector<pair<int,int>>v;
vector<bool>used;

void init(int N,vector<int>H){
    n=N; h=H;
    used.resize(n);
    for(int i=0;i<n;i++){
        v.pb({H[i],i});
    }
    sort(all(v));
    sg.init(n,h);
}

int max_towers(int L,int R,int D){
    int ans=0;
    set<int>st;
    st.insert(-1);
    st.insert(n);
    for(auto [x,i]:v){
        if(i<L||i>R) continue;
        bool add=true;
        auto it=st.lower_bound(i); it--; //*it is position
        if(*it!=-1){
            if(sg.query(1,0,n-1,(*it)+1,i-1)<x+D){
                add=false;
            }
        }
        it++;
        if(*it!=n){
            if(sg.query(1,0,n-1,i+1,(*it)-1)<x+D){
                add=false;
            }
        }
        if(add){
            ans++;
            st.insert(i);
        }
    }
    return ans;
}

• 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