Submission #728699

#	Time	Username	Problem	Language	Result	Execution time	Memory
728699		grogu	Rarest Insects (IOI22_insects)	C++17	53.14 / 100	218 ms	520 KiB

insects

#include "insects.h"
#define dbg(x) cerr<<#x<<": "<<x<<endl
#include <bits/stdc++.h>
#define ll int
#define pll pair<ll,ll>

using namespace std;
#define maxn 2005
ll n;
set<ll> s;
ll uniq = 0;
ll a[maxn];
ll F[maxn];
bool ok[maxn];
ll val[maxn];
ll cur = 0;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
void add(ll i){
    if(s.find(i)!=s.end()) return;
    move_inside(a[i]);
    s.insert(i);
}
void del(ll i){
    if(s.find(i)==s.end()){
        cerr<<"out"<<endl;
        return;
    }
    move_outside(a[i]);
    s.erase(i);
}
ll get(){return press_button();}
void klir(){
    while(s.size()) del(*s.begin());
}
set<ll> newe;
bool bad[maxn];
ll f(ll x){
    if(F[x]!=-1) return F[x];
    cur = get();
    newe.clear();
    for(ll i = 0;i<n;i++){
        if(ok[i]) continue;
        add(i);
        cur = get();
        if(cur>x) del(i);
        else newe.insert(i);
        if(s.size()==uniq*x) return F[x] = s.size();
    }
    return F[x] = s.size();
}
ll min_cardinality(ll N) {
    for(ll i = 0;i<maxn;i++) F[i] = -1;
    n = N;
    for(ll i = 0;i<n;i++) a[i] = i;
    shuffle(a,a+n,rng);
    uniq = f(1);
    for(ll x : s) ok[x] = 1;
    //dbg(uniq);
    ll l = 2, r = n/uniq,mid,rez = 1;
    while(l<=r){
        mid = (l+r)/2;
        if(f(mid)==uniq*mid){
            l = mid+1,rez = mid;
            for(ll x : s) ok[x] = 1;
        }else{
            r = mid-1;
            for(ll i = 0;i<n;i++){
                if(s.find(i)==s.end()) bad[i] = 1;
            }
            for(ll x : newe) del(x);
        }
    }
    return rez;
}
/**
6
5 8 9 5 9 9
**/

Compilation message (stderr)

insects.cpp: In function 'int f(int)':
insects.cpp:47:20: warning: comparison of integer expressions of different signedness: 'std::set<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   47 |         if(s.size()==uniq*x) return F[x] = s.size();
      |            ~~~~~~~~^~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 15 / 15
• Subtask 3: 28.14 / 75