#include <bits/stdc++.h>
using namespace std;
/// You may use:
// The number of students
int N;
// The probability any given student is positive
double P;
mt19937 rng(time(0));
vector<int> order;
// 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.
std::vector<bool> find_positive() {
vector<int> ids(N);
iota(ids.begin(), ids.end(), 0);
vector<bool> res(N);
int B = max(1, (int) (N / (1 / P)));
while (!ids.empty()) {
int n = (int) ids.size();
vector<bool> qv(N);
for (int i = 0; i < min(n, B); i++) {
qv[ids[i]] = true;
}
if (!test_students(qv)) {
vector<int> new_vec;
for (int i = min(n, B); i < n; i++) {
new_vec.push_back(ids[i]);
}
ids = new_vec;
continue;
}
int low = 0, high = min(n, B) - 1, pos = -1;
while (low <= high) {
int mid = (low + high) >> 1;
qv = vector<bool>(N, false);
for (int i = 0; i <= mid; i++) {
qv[ids[i]] = true;
}
if (test_students(qv)) {
pos = mid;
high = mid - 1;
} else {
low = mid + 1;
}
}
assert(pos != -1);
res[ids[pos]] = true;
vector<int> new_vec;
for (int i = pos + 1; i < n; i++) {
new_vec.push_back(ids[i]);
}
ids = new_vec;
}
return res;
}
int main() {
int T;
scanf("%d %lf %d", &N, &P, &T);
order.resize(N);
iota(order.begin(), order.end(), 0);
shuffle(order.begin(), order.end(), rng);
// 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;
}
Compilation message
Main.cpp: In function 'bool test_students(std::vector<bool>)':
Main.cpp:33:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
33 | scanf(" %c", &answer);
| ~~~~~^~~~~~~~~~~~~~~~
Main.cpp: In function 'int main()':
Main.cpp:89:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
89 | scanf("%d %lf %d", &N, &P, &T);
| ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:109:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
109 | scanf(" %c", &verdict);
| ~~~~~^~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
344 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
56 ms |
344 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
2552 ms |
344 KB |
Incorrect |
| 2 |
Halted |
0 ms |
0 KB |
- |
