| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 1125051 | tvladm2009 | COVID tests (CEOI24_covid) | C11 | 0 ms | 0 KiB |
#include <cassert>
#include <cstdio>
#include <string>
#include <vector>
/// You may use:
using namespace std;
#define ll long long
#define ld long double
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
// 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;
bool range(int l, int r) {
vector<bool> query(N);
for (int i = l; i <= r; i += 1) {
query[i] = 1;
}
return test_students(query);
}
void divide(int l, int r) {
if (range(l, r) == 0) {
return;
}
if (l == r) {
answer[l] = 1;
return;
}
int m = (l + r) / 2;
divide(l, m);
divide(m + 1, r);
}
vector<bool> find_positive() {
ord.resize(N);
answer.resize(N, 0);
divide(0, N - 1);
return answer;
}
int main() {
int T;
scanf("%d %lf %d", &N, &P, &T);
// You may perform any extra initialization here.
for (int i = 0; i < T; i++) {
std::vector<bool> answer = find_positive();
assert(answer.size() == (size_t)N);
std::string answer_str(N, ' ');
for (int j = 0; j < N; j++)
answer_str[j] = answer[j] ? '1' : '0';
printf("A %s\n", answer_str.c_str());
fflush(stdout);
char verdict;
scanf(" %c", &verdict);
if (verdict == 'W')
exit(0);
}
return 0;
}