Submission #827991

#	Time	Username	Problem	Language	Result	Execution time	Memory
827991		arnold518	Rarest Insects (IOI22_insects)	C++17	100 / 100	53 ms	336 KiB

insects

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

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

const int MAXN = 2000;

int A[MAXN+10], B[MAXN+10], P[MAXN+10];

int min_cardinality(int N)
{
	for(int i=0; i<N; i++) P[i]=i;
	random_shuffle(P, P+N);

	for(int i=0; i<N; i++)
	{
		move_inside(P[i]); A[i]=1;
		if(press_button()>1)
		{
			move_outside(P[i]); A[i]=0;
		}
	}
	int cnt=0;
	for(int i=0; i<N; i++) cnt+=A[i];
	for(int i=0; i<N; i++) if(A[i]) A[i]=0, B[i]=1;
	if(cnt==1) return N;
	if(cnt==2)
	{
		for(int i=0; i<N; i++) move_inside(P[i]);
		return N-press_button();
	}

	int lo=1, hi=N/cnt+1;
	int val=cnt;
	while(lo+1<hi)
	{
		int mid=lo+hi>>1, t=val;
		for(int i=0; i<N; i++)
		{
			if(t==mid*cnt) break;
			if(B[i]) continue;

			move_inside(P[i]); A[i]=1; t++;
			if(press_button()>mid)
			{
				move_outside(P[i]); A[i]=0; t--;
			}
		}

		if(t==mid*cnt)
		{
			lo=mid;
			for(int i=0; i<N; i++) if(!B[i] && A[i]) B[i]=1, A[i]=0, val++;
		}
		else
		{
			hi=mid;
			for(int i=0; i<N; i++) if(!B[i] && !A[i]) B[i]=2;
			for(int i=0; i<N; i++) if(A[i]) move_outside(P[i]), A[i]=0;
		}
	}
	return lo;
}

Compilation message (stderr)

insects.cpp: In function 'int min_cardinality(int)':
insects.cpp:40:13: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   40 |   int mid=lo+hi>>1, t=val;
      |           ~~^~~

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