Submission #1190310

#	Time	Username	Problem	Language	Result	Execution time	Memory
1190310		Amr	Radio Towers (IOI22_towers)	C++20	23 / 100	4082 ms	69280 KiB

towers

#include "towers.h"

#include <vector>
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int M = 1e5+7;
vector<int> a;
ll getlog[M];
ll n, Log;
ll d;
pair<ll,ll> sp[M][20], sp2[M][20];

pair<ll,ll> get_max(ll l , ll r)
{
    ll dif = r-l+1;
    ll my = getlog[dif];
    return max(sp[l][my], sp[r-(1<<my)+1][my]);
}
pair<ll,ll> get_min(ll l , ll r)
{
    ll dif = r-l+1;
    ll my = getlog[dif];
    return min(sp2[l][my], sp2[r-(1<<my)+1][my]);
}

void init(int N, std::vector<int> H) {

    n = N; a = H;
    for(int i = 0; i < n; i++) sp[i][0] = sp2[i][0] = {a[i],i};
    Log = log2(n)+1;
   // cout << Log << endl;
    for(int j = 1; j < Log; j++)
    {
        for(int i = 0; i < n; i++)
        {
            if(i+(1<<j)-1<n)  sp[i][j] = max(sp[i][j-1],sp[i+(1<<j-1)][j-1]);
            if(i+(1<<j)-1<n)  sp2[i][j] = min(sp2[i][j-1],sp2[i+(1<<j-1)][j-1]);
        }
    }
    getlog[0] = -1;
    for(int i = 1; i <= n; i++) getlog[i] = getlog[i/2]+1;

}
ll go(ll l, ll r, ll mxh)
{
    if(r<l) return 0;
   // cout << l << " " << r << " " << mxh << " " << get(l,r).second << endl;
    ll biggest = get_max(l,r).second;
    ll new_mxh = min(mxh,a[biggest]-d);
    if(get_min(l,r).first>mxh) return go(l,biggest-1,new_mxh) + go(biggest+1,r,new_mxh);
    else return max(1LL,go(l,biggest-1,new_mxh) + go(biggest+1,r,new_mxh));
}
int max_towers(int L, int R, int D) {
    d = D;
    return go(L,R,1e18);
}

• 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