| # | 제출 시각 | 아이디 | 문제 | 언어 | 결과 | 실행 시간 | 메모리 |
|---|---|---|---|---|---|---|---|
| 1269621 | silentloop | COVID tests (CEOI24_covid) | C++20 | 0 ms | 0 KiB |
#include <bits/stdc++.h>
#define ll long long
#define sz(x) int(x.size())
#define forn(i,n) for(i=0; i<n; i++)
#define all(x) x.begin(),x.end()
#define pb push_back
#define mp make_pair
#define fr first
#define se second
using namespace std;
/// You may use:
// The number of students
int N;
// The probability any given student is positive
double P;
// This function performs a test on a subset of samples.
// Its argument is a vector of Booleans of length N,
// where the i-th element is true if the i-th sample should be added to the mix.
// It returns true if (and only if) at least one of the samples in the mix is positive.
bool test_students(std::vector<bool> mask) {
assert(mask.size() == (size_t)N);
std::string mask_str(N, ' ');
for (int i = 0; i < N; i++)
mask_str[i] = mask[i] ? '1' : '0';
printf("Q %s\n", mask_str.c_str());
fflush(stdout);
char answer;
scanf(" %c", &answer);
return answer == 'P';
}
/// You should implement:
// This function will be called once for each test instance.
// It should use test_students to determine which samples are positive.
// It must return a vector of Booleans of length N,
// where the i-th element is true if and only if the i-th sample is positive.
vector<bool>answer;
void calc(ll l, ll r)
{
if(l>r)
return;
vector<bool>t(N,0);
ll i, piv, pos=l;
for(i=l; i<=r; i++)
t[i]=1;
if(test_students(t)==0)
return;
while(l<=r)
{
piv=(l+r)/2;
for(i=0; i<N; i++)
t[i]=0;
for(i=l; i<=piv; i++)
t[i]=1;
if(test_students(t))
{
pos=piv;
r=piv-1;
}
else
l=piv+1;
}
answer[pos]=1;
calc(pos+1,N-1);
}
std::vector<bool> find_positive() {
answer.resize(N,0);
calc(0,N-1);
return answer;
}