Submission #634213

#	Time	Username	Problem	Language	Result	Execution time	Memory
634213		flappybird	Rarest Insects (IOI22_insects)	C++17	100 / 100	70 ms	432 KiB

insects

#include "insects.h"
#include <bits/stdc++.h>
using namespace std;

#define MAX 2020

int chk[MAX];
int num[MAX];
int rnd[MAX];

int min_cardinality(int N) {
	int K;
	K = 0;
	int i;
	for (i = 0; i < N; i++) rnd[i] = i;
	for (i = N - 1; i >= 0; i--) swap(rnd[i], rnd[rand() % (i + 1)]);
	int on = 0;
	for (i = 0; i < N; i++) {
		move_inside(rnd[i]);
		if (press_button() > 1) move_outside(rnd[i]);
		else num[i] = 1, chk[i] = 1, on++;
	}
	int l, r;
	K = on;
	l = 1, r = N / K + 1;
	while (r - l > 1) {
		int mid = (l + r) / 2;
		vector<int> nb;
		for (i = 0; i < N; i++) {
			if (!chk[i] && !num[i]) {
				move_inside(rnd[i]);
				if (press_button() > mid) {
					nb.push_back(i);
					move_outside(rnd[i]);
				}
				else {
					chk[i] = 1;
					on++;
				}
			}
			if (on == mid * K) break;
		}
		if (on == mid * K) {
			for (i = 0; i < N; i++) if (chk[i]) num[i] = 1;
			l = mid;
		}
		else {
			for (auto v : nb) num[v] = -1;
			for (i = 0; i < N; i++) if (chk[i] && !num[i]) chk[i] = 0, move_outside(rnd[i]), on--;
			r = mid;
		}
	}
	return l;
}

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