Submission #1147924

#	Time	Username	Problem	Language	Result	Execution time	Memory
1147924		thunopro	COVID tests (CEOI24_covid)	C++20	25.38 / 100	836 ms	440 KiB

Main

#include<bits/stdc++.h>
using namespace std ; 
#define maxn 200009
#define ll long long 
#define pb push_back 
#define fi first 
#define se second 
#define left id<<1
#define right id<<1|1 
#define re exit(0); 
#define _lower(x) lower_bound(v.begin(),v.end(),x)-v.begin()+1 
#define TIME ( 1.0*clock() / CLOCKS_PER_SEC )
const int mod = 1e9+7 ;
const int INF = 1e9 ; 

typedef vector<int> vi ; 
typedef pair<int,int> pii ; 
typedef vector<pii> vii ; 

template < typename T > void chkmin ( T &a , T b ) { if ( a > b ) a = b ; } 
template < typename T > void chkmax ( T &a , T b ) { if ( a < b ) a = b ; } 

void add ( int &a , int b ) 
{
	a += b ; 
	if ( a >= mod ) a -= mod ; 
	if ( a < 0 ) a += mod ; 
}

void rf () 
{
	freopen ("bai1.inp","r",stdin) ;
}

mt19937 rng (time(0)) ; 

int _pow ( int a , int n ) 
{
	if ( n == 0 ) return 1 ; 
	int res = _pow (a,n/2) ; 
	if ( n % 2 ) return 1ll*res*res%mod*a%mod ; 
	else return 1ll*res*res%mod ; 
}


int n , test ; 
double p ; 
int P ; 
bool a [maxn] ; 
vector<bool> covid ; 
bool test_students ( vector<bool> mask ) ; 
vector<bool> find_positive () ; 

//#define LOCAL 
#ifdef LOCAL 
void precompute () 
{
	for ( int i = 0 ; i < n ; i ++ ) a [i] = rng () % 2 ; 
	for ( int i = 0 ; i < n ; i ++ ) cout << a [i] ; cout << endl ; 
}
#endif 
#ifndef LOCAL 
void precompute () 
{
	
}
#endif 
int main () 
{
	ios_base::sync_with_stdio(0); 
	cin.tie(0);cout.tie(0); 
//	rf () ;
	cin >> n >> p >> test ;
	precompute () ;  
	while ( test -- ) 
	{
		vector<bool> positive = find_positive () ; 
		cout << "A " ; for ( auto x : positive ) cout << x ; cout << endl ; 
		char result ; cin >> result ; 
		if ( result == 'W' ) return 0 ; 
	}
}


#ifdef LOCAL 
bool test_students ( string mask ) 
{
	bool has = 0 ; 
	for ( int i = 0 ; i < n ; i ++ ) if ( mask [i] == '1' ) has |= a [i] ; 
	return has ; 
}
#endif 

#ifndef LOCAL 
bool test_students ( string mask ) 
{
	cout << "Q " ; cout << mask ; cout << endl ; 
	char res ; cin >> res ; 
	return res == 'P' ;  
}
#endif 

bool query ( int l , int r ) 
{
	string students (n,'0') ; 
	for ( int i = l ; i <= r ; i ++ ) 
	{
		if ( covid [i] ) continue ; 
		students [i] = '1' ; 
	}
	return test_students (students) ; 
}
bool solve ( int L , int R ) 
{
	int l = L , r = R ; 
	int res = -1 ; 
	while ( l <= r ) 
	{
		int mid = (l+r)/2 ; 
		if ( query (l,mid) == 1 ) res = mid , r = mid - 1 ; 
		else l = mid + 1 ;  
	}
	if ( res == -1 ) return false ; 
	covid [res] = 1 ; P -- ; 
	return true ; 
}
vector<bool> find_positive () 
{
	covid.assign (n,0) ;
	P = p * n ; 

	while ( true ) 
	{
		if ( P <= 0 ) break ; 
		int last_P = P ; 
		int block = n / P * 2 ; 
		block = max (block,1) ; 
		int l = 0 ; 
		while ( true ) 
		{
			int r = min (n-1,l+block-1) ;
			bool temp = solve (l,r) ; 
			l += block ; 
			if ( r == n - 1 || l >= n ) break ; 
		}
		if ( P == last_P ) break ; 
	}
	while ( solve (0,n-1) ) ; 
	return covid ; 
}

Compilation message (stderr)

Main.cpp: In function 'void rf()':
Main.cpp:32:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   32 |         freopen ("bai1.inp","r",stdin) ;
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 0: 0 / 0
• Subtask 1: 0 / 10
• Subtask 2: 25.38 / 90