Submission #1077751

#	Time	Username	Problem	Language	Result	Execution time	Memory
1077751		pcc	Rarest Insects (IOI22_insects)	C++17	54.05 / 100	124 ms	1516 KiB

insects

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

const int mxn = 2022;
vector<int> v[mxn];
set<int> st;
int N;
int cnt = 0;
const int B = 4;

void del(int k){
	assert(st.find(k) != st.end());
	st.erase(k);
	move_outside(k);
	return;
}

void add(int k){
	assert(st.find(k) == st.end());
	st.insert(k);
	move_inside(k);
	return;
}

int ask(){
	int re = press_button();
	return re;
}

bool check(int lim){
	for(int i = lim+1;i<=N;i++){
		while(!v[i].empty()){
			auto now = v[i].back();
			v[i].pop_back();
			del(now);
		}
	}
	for(int i = 0;i<N;i++){
		if(st.find(i) == st.end()){
			add(i);
			int re = ask();
			if(re>lim)del(i);
			else v[re].push_back(i);
		}
	}
	return lim*cnt == st.size();
}

int min_cardinality(int NN) {
	N = NN;
	check(1);
	cnt = st.size();
	if(N/cnt<=B){
		for(int i = 2;i<=N/cnt;i++){
			if(!check(i))return i-1;
		}
		return N/cnt;
		assert(false);
	}
	int l = 1,r = N/cnt;
	while(l != r){
		int mid = (l+r+1)>>1;
		if(check(mid))l = mid;
		else r = mid-1;
	}
	return l;
}

Compilation message (stderr)

insects.cpp: In function 'bool check(int)':
insects.cpp:47:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::set<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   47 |  return lim*cnt == st.size();
      |         ~~~~~~~~^~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 15 / 15
• Subtask 3: 29.05 / 75