Submission #626096

#	Time	Username	Problem	Language	Result	Execution time	Memory
626096		nigus	Radio Towers (IOI22_towers)	C++17	44 / 100	4037 ms	46660 KiB

towers

#include <bits/stdc++.h>
using namespace std;

#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define trav(a, x) for(auto& a : x)
#define all(x) x.begin(), x.end()
#define sz(x) (int)(x).size()
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<ll> vl;

const ll big = 1000000007;
const int MAXN = 100001;
int n;
vi H2;

struct Segtree {
	Segtree *l = 0, *r = 0;
	int lo, hi, ma = -big, mi = big, ab = 0, ba = 0;
    vi V;
	Segtree(vi& v, int lo, int hi) : lo(lo), hi(hi) {
		if (lo + 1 < hi) {
			int mid = lo + (hi - lo)/2;
			l = new Segtree(v, lo, mid); r = new Segtree(v, mid, hi);
			ma = max(l->ma, r->ma);
            mi = min(l->mi, r->mi);
            ab = max(l->ab, r->ab);
            ab = max(ab, (r->ma) - (l->mi));
            ba = max(l->ba, r->ba);
            ba = max(ba, (l->ma) - (r->mi));
		}
		else{
            ma = v[lo];
            mi = v[lo];
        }
	}
    void setup(vi &v){
        if(lo + 1 < hi){
            l->setup(v);
            r->setup(v);
            V = (l->V);
            trav(y, r->V){
                V.push_back(y);
            }
            sort(all(V));
            reverse(all(V));
        }
        else{
            V = {v[lo]};
        }
    }
	int get_max(int L, int R) {
		if (R <= lo || hi <= L) return -big;
		if (L <= lo && hi <= R) return ma;
		return max(l->get_max(L, R), r->get_max(L, R));
	}
    int get_min(int L, int R) {
		if (R <= lo || hi <= L) return big;
		if (L <= lo && hi <= R) return mi;
		return min(l->get_min(L, R), r->get_min(L, R));
	}
    int get_ab(int L, int R){
        if (R <= lo || hi <= L) return 0;
		if (L <= lo && hi <= R) return ab;

        int res = (l->get_ab(L, R));
        if(res < r->ab){
            res = max(res, r->get_ab(L, R));
        }
        if(res < (r->ma) - (l->mi)){
            int x = l->get_min(L,R);
            int y = r->get_max(L,R);
            res = max(res, y-x);
        }

        return res;
    }
    int get_ba(int L, int R){
        if (R <= lo || hi <= L) return 0;
		if (L <= lo && hi <= R) return ba;

        int res = l->get_ba(L, R);
        if(res < r->ba){
            res = max(res, r->get_ba(L, R));
        }
        if(res < (l->ma) - (r->mi)){
            int x = r->get_min(L, R);
            int y = l->get_max(L, R);
            res = max(res, y-x);
        }

        return res;
    }
    int geq(int L, int R, int D){
        if (R <= lo || hi <= L) return 0;
        if (L <= lo && hi <= R){
            int lo = 0;
            int hi = sz(V);
            if(V[0] < D)return 0;
            while(lo < hi-1){
                int mid = (lo + hi) / 2;
                if(V[mid] < D){
                    hi = mid;
                }
                else{
                    lo = mid;
                }
            }
            return hi;
        }
        return (l->geq(L, R, D)) + (r->geq(L, R, D));
    }
};

Segtree *ST;

map<int,int> HI;

vi delta;

vi ind;

void get_ct(int L, int R){
    if(L >= R)return;
    if(L == R-1){
        delta[L] = 0;
        return;
    }
    int i = HI[ST->get_max(L, R)];
    int x = ST->get_min(L,i);
    int y = ST->get_min(i+1,R);
    delta[i] = H2[i]-max(x, y);
    delta[i] = max(delta[i], 0);
    get_ct(L, i);
    get_ct(i+1,R);
}

bool comp(int i, int j){
    return delta[i] > delta[j];
}

void init(int N, vi H){
    n = N;
    rep(c1,0,n){
        H2.push_back(H[c1]);
        HI[H[c1]] = c1;
        ind.push_back(c1);
        delta.push_back(0);
    }
    ST = new Segtree(H2, 0, n);
    get_ct(0, n);
    sort(all(ind), comp);
    ST->setup(delta);
}

unordered_map<ll,int> M;

int first_ab(ll L, ll R, ll D){

    ll h = 2*(L*big + D);
    if(M.find(h) != M.end())return M[h];

    int lo = L;
    int hi = R;
    while(lo < hi-1){
        int mid = (lo+hi)/2;
        if(ST->get_ab(L, mid+1) < D){
            lo = mid;
        }
        else{
            hi = mid;
        }
    }
    M[h] = hi;

    return hi;
}

int last_ba(ll L, ll R, ll D){

    ll h = 2*(R*big + D) + 1;
    if(M.find(h) != M.end())return M[h];

    int lo = L;
    int hi = R;
    while(lo < hi-1){
        int mid = (lo+hi)/2;
        if(ST->get_ba(mid, R) >= D){
            lo = mid;
        }
        else{
            hi = mid;
        }
    }
    M[h] = lo;

    return lo;
}

int max_towers(int L, int R, int D){
    R++;

    if(ST->get_ab(L, R) < D || ST->get_ba(L, R) < D)return 1;
    int i = first_ab(L, R, D);
    int j = last_ba(L, R, D)+1;
    return (ST->geq(i,j,D))+1;
}


/*
int main() {

    int N;
    N = 7;
    vi H = {1,4,2,9,3,6,5};
    init(N,H);

    cout << max_towers(0, 7, 1) << "\n";
    cout << max_towers(0, 7, 2) << "\n";
    cout << max_towers(0, 7, 3) << "\n";
    cout << max_towers(0, 7, 10) << "\n";


    return 0;
}
*/

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