Submission #837827

#	Time	Username	Problem	Language	Result	Execution time	Memory
837827		fatemetmhr	Rarest Insects (IOI22_insects)	C++17	25 / 100	83 ms	924 KiB

insects

// Be name khoda //

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

using namespace std;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

#define debug(x) cerr << "(" << (#x) << "): " << (x) << endl;
#define all(x)   x.begin(), x.end()
#define pb       push_back
#define mp       make_pair
#define fi       first
#define se       second

typedef long long ll;

const int mod   = 1e9 + 9;
const int maxn5 = 1e5 + 10;

int dif, n, pw[maxn5], per[maxn5], hsh = 0;
bool mark[maxn5];
vector <int> av;
map <int, int> asked;


void fix(int &a){
    if(a < 0)
        a += mod;
    if(a >= mod)
        a -= mod;
}

void mmove_outside(int x){
    x = per[x];
    move_outside(x);
    fix(hsh -= pw[x]);
}

void mmove_inside(int x){
    x = per[x];
    move_inside(x);
    fix(hsh += pw[x]);
}

int ppress_button(){
    if(asked.find(hsh) == asked.end())
        asked[hsh] = press_button();
    return asked[hsh];
}

int find_all_same(int id){
    mark[id] = true;
    mmove_inside(id);
    int cnt = 1;
    for(int i = 0; i < n; i++) if(!mark[i]){
        mmove_inside(i);
        if(ppress_button() == 2){
            mark[i] = true;
            cnt++;
        }
        mmove_outside(i);
    }
    mmove_outside(id);
    return cnt;
}

int count_dif(){
    av.clear();
    hsh = 0;
    for(int i = 0; i < n; i++){
        mmove_inside(i);
        av.pb(i);
        if(ppress_button() == 2){
            mmove_outside(i);
            av.pop_back();
        }
    }
    for(auto u : av)
        mmove_outside(u);
    return av.size();
}

bool check(int x){
    av.clear();
    hsh = 0;
    for(int i = 0; i < n; i++){
        av.pb(i);
        mmove_inside(i);
        if(i + 1 > x && ppress_button() > x){
            mmove_outside(i);
            av.pop_back();
        }
        if(int(av.size()) == x * dif)
            return true;
        if(int(av.size()) + n - i - 1 < x * dif)
            break;
    }
    for(auto u : av)
        mmove_outside(u);
    return false;
}

int min_cardinality(int N) {
    n = N;
    pw[0] = 1;
    for(int i = 0; i < n; i++){
        per[i] = i;
        if(i)
            pw[i] = pw[i - 1] * 7ll % mod;
    }
    shuffle(per, per + n, rng);
    dif = count_dif();
    if(dif == 1)
        return n;
    if(dif <= 8){
        int mn = n;
        for(int i = 0; i < n; i++) if(!mark[i]){
            mn = min(mn, find_all_same(i));
            if(mn == 1)
                return 1;
        }
        return mn;
    }
    int lo = 1, hi = n / dif + 1;
    while(hi - lo > 1){
        int mid = (lo + hi) >> 1;
        if(check(mid))
            lo = mid;
        else
            hi = mid;
    }
    return lo;
}

• Subtask 1: 10 / 10
• Subtask 2: 15 / 15
• Subtask 3: 0 / 75