#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;
// 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';
}
// test = false means we know that there is at least 1 positive result in this
// range
bool recurse(int L, int R, vector<bool> &ans, bool test) {
vector<bool> msk(ans.size());
for (int i = L; i <= R; i++) {
msk[i] = true;
}
bool q = true;
if (test)
q = test_students(msk);
if (q == 1) {
if (L == R) {
ans[L] = true;
} else {
int m = (L + R) / 2;
bool a1 = recurse(L, m, ans, true);
if (!a1) {
recurse(m + 1, R, ans, false);
} else {
recurse(m + 1, R, ans, true);
}
}
}
return q;
}
/// 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() {
std::vector<bool> answer(N);
/*int cur = (int)(1.0 / P);*/
/*cur = (1 << max(30 - __builtin_clz(cur), 1));*/
/*int init_sz = max((int)(log(0.5) / log(max(1 - P, 1e-9))), 1);*/
int init_sz = 128;
int cur_sz = init_sz;
int i = 0;
while (i < N) {
vector<bool> msk(answer.size());
for (int j = i; j <= min(i + cur_sz - 1, N - 1); j++) {
msk[j] = true;
}
bool q = test_students(msk);
if (q) {
if (cur_sz == 1) {
answer[i] = true;
i += cur_sz;
cur_sz = init_sz;
} else {
cur_sz /= 2;
}
} else {
i += cur_sz;
}
}
/*recurse(0, N - 1, answer);*/
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;
}
Compilation message (stderr)
Main.cpp: In function 'bool test_students(std::vector<bool>)':
Main.cpp:28:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
28 | scanf(" %c", &answer);
| ~~~~~^~~~~~~~~~~~~~~~
Main.cpp: In function 'int main()':
Main.cpp:97:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
97 | scanf("%d %lf %d", &N, &P, &T);
| ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:113:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
113 | scanf(" %c", &verdict);
| ~~~~~^~~~~~~~~~~~~~~~~
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