Submission #726986

#	Time	Username	Problem	Language	Result	Execution time	Memory
726986		murad_2005	Rarest Insects (IOI22_insects)	C++17	100 / 100	65 ms	484 KiB

insects

#include "insects.h"
#include <bits/stdc++.h>
#define ll long long
#define ull unsigned ll
#define pii pair<int, int>
#define piii pair<int, pii>
#define pb push_back
#define all(v) v.begin(), v.end()
#define size(v) v.size()
#define f first
#define s second
#define INF 1e9

using namespace std;

int min_cardinality(int N) {
    vector<int>inside(N, false);
    vector<int>fixed(N, false);
    set<int>Machine;
    for(int i = 0; i < N; ++i){
        move_inside(i);
        if(press_button() > 1){
            move_outside(i);
        }else{
            Machine.insert(i);
            inside[i] = fixed[i] = true;
        }
    }
    int uni = size(Machine);
    vector<int>p(N);
    for(int i = 0; i < N; ++i){
        p[i] = i;
    }

    random_shuffle(all(p));

    int low = 2, high = N / uni, Res = 1;
    while(low <= high){
        int mid = (low + high) >> 1;
        for(int i : p){
            if(uni * mid == size(Machine)) break;
            if(!fixed[i]){
                move_inside(i);
                if(press_button() > mid){
                    move_outside(i);
                }else{
                    Machine.insert(i);
                    inside[i] = true;
                }
            }
        }
        if(uni * mid == size(Machine)){
            low = mid + 1;
            Res = mid;
            for(int i = 0; i < N; ++i){
                if(inside[i]) fixed[i] = true;
            }
        }else{
            high = mid - 1;
            for(int i = 0; i < N; ++i){
                if(!inside[i]) fixed[i] = true;
                else if(!fixed[i]){
                    move_outside(i);
                    Machine.erase(i);
                    inside[i] = false;
                }
            }
        }
    }
    return Res;
}

Compilation message (stderr)

insects.cpp: In function 'int min_cardinality(int)':
insects.cpp:41:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::set<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   41 |             if(uni * mid == size(Machine)) break;
      |                          ^
insects.cpp:52:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::set<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   52 |         if(uni * mid == size(Machine)){
      |                      ^

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