Submission #1186012

#	Time	Username	Problem	Language	Result	Execution time	Memory
1186012		anmattroi	Rarest Insects (IOI22_insects)	C++17	100 / 100	15 ms	452 KiB

insects

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

using namespace std;

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

vector<int> p;

int cnt;

int pressButton() {
    return press_button();
}

void moveInside(int i) {
    move_inside(p[i]);
}

void moveOutside(int i) {
    move_outside(p[i]);
}

int minCardinality(int N) {
    vector<int> candidates(N);
    iota(candidates.begin(), candidates.end(), 0);

    int coef = 0;

    int lo = 1, hi = N/cnt+1;
    while (hi - lo > 1) {
        hi = min(hi, coef + int(candidates.size() / cnt) + 1);
        int mid = (lo + hi) >> 1;
//        cout << lo << ' ' << mid << ' ' << hi << ' ' << candidates.size() << "\n";
        vector<int> inside, outside;
        int fl = 0;
        for (int i : candidates) {
            if (coef * cnt + int(inside.size()) == mid*cnt || fl) {
                fl = 1;
                outside.emplace_back(i);
                continue;
            }
            moveInside(i);
            if (pressButton() > mid) {
                moveOutside(i);
                outside.emplace_back(i);
            } else inside.emplace_back(i);
        }

        if (coef * cnt + int(inside.size()) == mid * cnt) {
            lo = mid;
            coef = mid;
            candidates = outside;
        } else {
            for (int i : inside) moveOutside(i);
            hi = mid;
            candidates = inside;
        }
    }
    return lo;
}
/*
9
4 4 4 4 3 3 3 3 3 3
*/
/*
4
2 2 2 3
*/

int min_cardinality(int N) {
    p.assign(N, 0);
    iota(p.begin(), p.end(), 0);
    shuffle(p.begin(), p.end(), rng);
    shuffle(p.begin(), p.end(), rng);
    shuffle(p.begin(), p.end(), rng);
    shuffle(p.begin(), p.end(), rng);
    shuffle(p.begin(), p.end(), rng);
    shuffle(p.begin(), p.end(), rng);

    vector<int> e;
    for (int i = 0; i < N; i++) {
        moveInside(i);
        if (pressButton() > 1) moveOutside(i);
        else {
            e.emplace_back(i);
            ++cnt;
        }
    }
    for (int i : e) moveOutside(i);
    if (cnt == 1) return N;
    if (cnt == 2) {
        for (int i = 0; i < N; i++) moveInside(i);
        int T = pressButton();
        int O = N-T;
        if (O == 0) O = INT_MAX;
        return min(O, T);
    }
    if (cnt == N-1) return 1;
    if (cnt == N) return 1;


    return minCardinality(N);
}

• Subtask 1: 10 / 10
• Subtask 2: 15 / 15
• Subtask 3: 75 / 75