Submission #774662

#	Time	Username	Problem	Language	Result	Execution time	Memory
774662		Magikarp4000	Radio Towers (IOI22_towers)	C++17	14 / 100	865 ms	5456 KiB

towers

#include "towers.h"
#include <bits/stdc++.h>
using namespace std;
#define OPTM ios_base::sync_with_stdio(0); cin.tie(0);
#define INF int(1e9+7)
#define ln '\n' 
#define ll long long
#define ull unsigned long long
#define ui unsigned int
#define us unsigned short
#define FOR(i,s,n) for (int i = s; i < n; i++)
#define FORR(i,n,s) for (int i = n; i > s; i--)
#define FORX(u, arr) for (auto u : arr)
#define PB push_back
#define in(v,x) (v.find(x) != v.end())
#define F first
#define S second
#define PII pair<int, int>
#define PLL pair<ll, ll>
#define UM unordered_map
#define US unordered_set
#define PQ priority_queue
#define ALL(v) v.begin(), v.end()
const ll LLINF = 1e18+1;

const int MAXN = 1e5+5;
int n,l,r,d;
int h[MAXN], le[MAXN], ri[MAXN], p[MAXN];
bool done;
bool z[MAXN];

void precalc() {
    PQ<PII> pq;
    FOR(i,0,n) {
        while (!pq.empty() && -pq.top().F <= h[i]-d) {
            ri[pq.top().S] = i;
            pq.pop();
        }
        pq.push({-h[i],i});
    }
    while (!pq.empty()) {
        ri[pq.top().S] = n;
        pq.pop();
    }
    FORR(i,n-1,-1) {
        while (!pq.empty() && -pq.top().F <= h[i]-d) {
            le[pq.top().S] = i;
            pq.pop();
        }
        pq.push({-h[i],i});
    }
    while (!pq.empty()) {
        le[pq.top().S] = -1;
        pq.pop();
    }
    vector<PII> v;
    FOR(i,0,n) v.PB({h[i],i});
    int vn = v.size();
    sort(ALL(v));
    set<int> s;
    s.insert(-INF);
    s.insert(INF);
    FOR(i,0,vn) {
        int idx = v[i].S;
        auto it = s.lower_bound(idx);
        auto it1 = it;
        it1--;
        if (le[idx] > (*it1) && ri[idx] < (*it)) s.insert(idx);
    }
    s.erase(-INF);
    s.erase(INF);
    FORX(u,s) {
        p[u+1]++;
        z[u] = 1;
    }
    FOR(i,1,n+1) p[i] += p[i-1];
    // FOR(i,0,n) cout << z[i] << " ";
    // cout << ln;
}

void init(int N, std::vector<int> H) {
    n = N;
    FOR(i,0,n) h[i] = H[i];
}

int max_towers(int L, int R, int D) {
    l = L, r = R, d = D;
    if (!done) {
        precalc();
        done = 1;
    }
    if (l == r) return 1;
    int res = p[r+1]-p[l];
    if (!z[l] && (l+1 >= n || h[l+1] > h[l])) res++;
    if (!z[r] && (r-1 < 0 || h[r-1] > h[r])) res++;
    // FOR(i,0,n) cout << le[i] << " ";
    // cout << ln;
    // FOR(i,0,n) cout << ri[i] << " ";
    // cout << ln;
    return res;
}

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