Submission #1076850

#	Time	Username	Problem	Language	Result	Execution time	Memory
1076850		Zicrus	Rarest Insects (IOI22_insects)	C++17	54.04 / 100	164 ms	1252 KiB

insects

#include <bits/stdc++.h>
#include "insects.h"
using namespace std;
 
typedef long long ll;
 
int n;
vector<bool> in;
unordered_set<int> sIn, sOut;
int cnt;
int numA, numP;

mt19937 mt;
 
void add(int i) {
    if (in[i]) return;
    numA++;
    move_inside(i);
    cnt++;
    in[i] = true;
}

int add_rand() {
    int id = mt() % sOut.size();
    auto iter = sOut.begin();
    while (id--) iter++;
    int i = *iter;
    add(i);
    sOut.erase(i);
    return i;
}

void remove(int i) {
    if (!in[i]) return;
    move_outside(i);
    cnt--;
    in[i] = false;
}

int remove_rand() {
    int id = mt() % sIn.size();
    auto iter = sIn.begin();
    while (id--) iter++;
    int i = *iter;
    remove(i);
    sIn.erase(i);
    return i;
}

int press() {
    numP++;
    return press_button();
}
 
int min_cardinality(int N) {
    n = N;
    cnt = 0;
    numA = numP = 0;
    mt = mt19937(time(0));
    in = vector<bool>(n);
    int cur = 0;
    
    for (int i = 0; i < n; i++) {
        add(i);
        cur = press();
        if (cur > 1) {
            remove(i);
            sOut.insert(i);
            cur = 1;
        }
    }
    int typeCnt = cnt;
    
    int left = 1, right = n / typeCnt;
    bool up = true;
    restart:
    while (left < right) {
        int mid = (left + right + 1) / 2;

        unordered_set<int> later;
        try_up:
        if (up) {
            while (cnt < typeCnt * mid) {
                if (sOut.empty()) {
                    right = mid - 1;
                    up = false;
                    for (auto &e : later) sOut.insert(e);
                    later.clear();
                    goto restart;
                }
                
                int inc = mid - cur + 1;
                int recent = -1;
                while (!sOut.empty() && inc--) {
                    recent = add_rand();
                    sIn.insert(recent);
                }
                cur = press();
                if (cur > mid) {
                    remove(recent);
                    sIn.erase(recent);
                    later.insert(recent);
                    cur = mid;
                }
            }
            left = mid;
            up = true;
            sIn.clear();
            for (auto &e : later) sOut.insert(e);
            later.clear();
        }
        else {
            while (cur > mid) {
                int dec = cur - mid + 1;
                int recent = -1;
                while (dec--) {
                    recent = remove_rand();
                    sOut.insert(recent);
                }
                cur = press();
                if (cur < mid) {
                    add(recent);
                    sOut.erase(recent);
                    later.insert(recent);
                    cur = mid;
                }
            }
            up = true;
            for (auto &e : later) sIn.insert(e);
            later.clear();
            goto try_up;
        }
    }

    return left;
} 
 
#ifdef TEST
#include "grader.cpp"
#endif

• Subtask 1: 10 / 10
• Subtask 2: 15 / 15
• Subtask 3: 29.04 / 75