Submission #936665

#	Time	Username	Problem	Language	Result	Execution time	Memory
936665		GrindMachine	Rarest Insects (IOI22_insects)	C++17	71.41 / 100	73 ms	1632 KiB

insects

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
 
using namespace std;
using namespace __gnu_pbds;
 
template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
 
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) (int)a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x,y) ((x+y-1)/(y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl
 
#define rep(i,n) for(int i = 0; i < n; ++i)
#define rep1(i,n) for(int i = 1; i <= n; ++i)
#define rev(i,s,e) for(int i = s; i >= e; --i)
#define trav(i,a) for(auto &i : a)
 
template<typename T>
void amin(T &a, T b) {
    a = min(a,b);
}
 
template<typename T>
void amax(T &a, T b) {
    a = max(a,b);
}
 
#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif
 
/*
 
 
 
*/
 
const int MOD = 1e9 + 7;
const int N = 1e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;
 
#include "insects.h"
 
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

int go(vector<int> uniq_guys, vector<int> pos){
    shuffle(all(uniq_guys),rng);

    int uniq = sz(uniq_guys);
    if(uniq == 1){
        return sz(pos);
    }
    if(sz(pos) < uniq*2){
        return 1;
    }

    int mid = uniq/2;
    vector<int> uniq_l, uniq_r;
    vector<int> pos_l, pos_r;
    
    rep(ind,uniq){
        int i = uniq_guys[ind];
        if(ind < mid){
            move_inside(i);
            uniq_l.pb(i);
            pos_l.pb(i);
        }
        else{
            uniq_r.pb(i);
            pos_r.pb(i);
        }
    }

    set<int> st(all(uniq_guys));

    trav(i,pos){
        if(st.count(i)){
            conts;
        }

        move_inside(i);

        int res = press_button();
        if(res == 2){
            pos_l.pb(i);
        }
        else{
            pos_r.pb(i);
        }

        move_outside(i);
    }

    trav(i,uniq_l){
        move_outside(i);
    }

    int ans = min(go(uniq_l,pos_l), go(uniq_r,pos_r));
    return ans;
}

int min_cardinality(int n) {
    set<int> uniq_guys;
 
    rep(i,n){
        move_inside(i);
        int res = press_button();
        if(res >= 2){
            move_outside(i);
        }
        else{
            uniq_guys.insert(i);
        }
    }

    trav(i,uniq_guys){
        move_outside(i);
    }
    
    if(sz(uniq_guys) == 1){
        return n;
    }

    if(sz(uniq_guys) == n){
        return 1;
    }

    int cost1 = __lg(n/sz(uniq_guys)-1)+1;
    int cost2 = __lg(sz(uniq_guys)-1)+1;

    if(cost2 <= cost1){
        vector<int> v1(all(uniq_guys));
        vector<int> v2(n);
        rep(i,n) v2[i] = i;
        int ans = go(v1,v2);
        return ans;
    }

    vector<bool> ignore(n);

    auto ok = [&](int mid){
        vector<int> good, bad;
 
        rev(i,n-1,0){
            if(ignore[i]) conts;
            move_inside(i);
            int res = press_button();
            if(res > mid){
                bad.pb(i);
                move_outside(i);
            }
            else{
                good.pb(i);
            }
        }
 
        trav(i,good){
            move_outside(i);
        }

        int curr_uniq = 0;
        trav(i,bad){
            curr_uniq += uniq_guys.count(i);
        }

        if(curr_uniq >= sz(uniq_guys)) return false;
            
        trav(i,bad){
            if(uniq_guys.count(i)){
                uniq_guys.erase(i);
            }
            ignore[i] = 1;
        }

        return true;        
    };

    int l = 1, r = n/sz(uniq_guys)-1;
    int ans = n/sz(uniq_guys);
 
    while(l <= r){
        int mid = (l+r) >> 1;
        // is min <= mid?
        if(ok(mid)){
            ans = mid;
            r = mid-1;
        }
        else{
            l = mid+1;
        }
    }
 
    return ans;
}

• Subtask 1: 10 / 10
• Subtask 2: 15 / 15
• Subtask 3: 46.41 / 75