Submission #1058454

#	Time	Username	Problem	Language	Result	Execution time	Memory
1058454		fuad27	Rarest Insects (IOI22_insects)	C++17	0 / 100	40 ms	1472 KiB

insects

#include "insects.h"
#include <bits/stdc++.h>
using namespace std;
int min_cardinality(int N) {
	int distcnt = 0;
	set<int> idxs;
	mt19937 rng(time(0));
	vector<int> alll(N);
	iota(alll.begin(), alll.end() ,0);
	shuffle(alll.begin(), alll.end(), rng);
	for(int i:alll) {
		move_inside(i);
		if(press_button() <= 1){
			idxs.insert(i);
			distcnt++;
			continue;
		}
		move_outside(i);
	}
	set<int> all_idxs[N+1];
	all_idxs[1] = idxs;
	int ans=1;
	int prev = 1;
	int lo = 2, hi = N/distcnt;
	while(lo <= hi) {
		int mid = (lo+hi)/2;
		if(prev < mid) {
			for(int j:alll) {
				if(idxs.find(j)!=idxs.end())continue;
				move_inside(j);
				int val = press_button();
				idxs.insert(j);
				if(val == mid*distcnt)break;
				if(val <= mid) {
					continue;
				}
				idxs.erase(j);
				move_outside(j);
			}
		}
		else {
			int cur = 1;
			for(int j = 1;j<mid;j++) {
				if(all_idxs[j].size() > all_idxs[cur].size()) {
					cur=j;
				}
			}
			vector<int> er;
			for(int j:idxs) {
				if(all_idxs[cur].find(j)==all_idxs[cur].end()) {
					er.push_back(j);
				}
			}
			int curn=0;
			for(int j = mid+1;j<N;j++) {
				if(all_idxs[j].size()) {
					cur=j;
					break;
				}
			}
			for(int j:er){
				move_outside(j);
				idxs.erase(j);
			}
			for(int j:alll) {
				if(idxs.find(j)!=idxs.end())continue;
				if(all_idxs[cur].find(j)==all_idxs[cur].end())continue;
				move_inside(j);
				int val = press_button();
				idxs.insert(j);
				if(idxs.size() == mid*distcnt)break;
				if(val <= mid) {
					continue;
				}
				idxs.erase(j);
				move_outside(j);
			}
		}
		if(idxs.size() == distcnt*mid) {
			lo = mid+1;
			ans=mid;
		}
		else {
			hi=mid-1;
		}
		all_idxs[mid] = idxs;
		prev=mid;
	}
	return ans;
}

Compilation message (stderr)

insects.cpp: In function 'int min_cardinality(int)':
insects.cpp:71:20: warning: comparison of integer expressions of different signedness: 'std::set<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   71 |     if(idxs.size() == mid*distcnt)break;
      |        ~~~~~~~~~~~~^~~~~~~~~~~~~~
insects.cpp:54:8: warning: unused variable 'curn' [-Wunused-variable]
   54 |    int curn=0;
      |        ^~~~
insects.cpp:79:18: warning: comparison of integer expressions of different signedness: 'std::set<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   79 |   if(idxs.size() == distcnt*mid) {
      |      ~~~~~~~~~~~~^~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 15
• Subtask 3: 0 / 75