// AM + DG
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<ll> vll;
typedef vector<vll> vvll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<ll, ll> pll;
typedef vector<pll> vpll;
typedef pair<int, int> pi;
typedef vector<pi> vpi;
typedef vector<bool> vb;
typedef vector<double> vd;
#define fi first
#define se second
#define IOS cin.tie(nullptr); cout.tie(nullptr); ios_base::sync_with_stdio(false)
#define pb push_back
#define INF(dtype) numeric_limits<dtype>::max()
#define NINF(dtype) numeric_limits<dtype>::min()
/// You may use:
// The number of students
int N;
// The probability any given student is positive
double P;
// The size of the set that maximizes entropy/"surprise"
// int k;
vd dp;
vi dpi;
// 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.
void solve(int l, int r, vb& answer) {
vb mask(N, false);
int sz = r - l + 1;
int lsz = dpi[sz];
for(int i = l; i <= r; i++) mask[i] = true;
bool res = test_students(mask);
for(int i = l; i <= r; i++) mask[i] = false;
if(!res) {
for(int i = l; i <= r; i++) answer[i] = false;
} else if(l == r) {
answer[l] = true;
} else {
if(lsz > 0) {
int m = l + lsz - 1;
solve(l, m, answer);
solve(m + 1, r, answer);
} else {
// brute force
for(int i = l; i <= r; i++) {
mask[i] = true;
answer[i] = test_students(mask);
mask[i] = false;
}
}
}
}
std::vector<bool> find_positive() {
std::vector<bool> answer(N);
solve(0, N - 1, answer);
return answer;
}
int main() {
int T;
scanf("%d %lf %d", &N, &P, &T);
// You may perform any extra initialization here.
// Compute size of set that maximizes "surprisal"
// k = max((int)lround(-1.0 / log2(1.0 - P)), 1);
dp = vd(N + 1);
dpi = vi(N + 1);
dp[0] = 0.0;
dp[1] = 1.0;
double onemp = 1.0 - P;
for(int i = 2; i <= N; i++) {
double min_ans = INF(double);
int min_ind = 1;
for(int j = 0; j < i; j++) {
double onemppwk = pow(onemp, j);
double cand = onemppwk + (1.0 - onemppwk) * (dp[j] + 1.0);
if(cand < min_ans) {
min_ans = cand;
min_ind = j;
}
}
dp[i] = min_ans;
dpi[i] = min_ind;
}
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:50:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
50 | scanf(" %c", &answer);
| ~~~~~^~~~~~~~~~~~~~~~
Main.cpp: In function 'int main()':
Main.cpp:103:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
103 | scanf("%d %lf %d", &N, &P, &T);
| ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:148:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
148 | scanf(" %c", &verdict);
| ~~~~~^~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
344 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
21 ms |
344 KB |
Output is correct |
| 2 |
Correct |
16 ms |
344 KB |
Output is correct |
| 3 |
Correct |
20 ms |
444 KB |
Output is correct |
| 4 |
Correct |
16 ms |
344 KB |
Output is correct |
| 5 |
Correct |
20 ms |
344 KB |
Output is correct |
| 6 |
Correct |
23 ms |
344 KB |
Output is correct |
| 7 |
Correct |
16 ms |
344 KB |
Output is correct |
| 8 |
Correct |
15 ms |
344 KB |
Output is correct |
| 9 |
Correct |
15 ms |
344 KB |
Output is correct |
| 10 |
Correct |
15 ms |
344 KB |
Output is correct |
| 11 |
Correct |
16 ms |
440 KB |
Output is correct |
| 12 |
Correct |
16 ms |
356 KB |
Output is correct |
| 13 |
Correct |
16 ms |
344 KB |
Output is correct |
| 14 |
Correct |
13 ms |
344 KB |
Output is correct |
| 15 |
Correct |
13 ms |
344 KB |
Output is correct |
| 16 |
Correct |
9 ms |
344 KB |
Output is correct |
| 17 |
Correct |
6 ms |
344 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1370 ms |
344 KB |
Incorrect |
| 2 |
Halted |
0 ms |
0 KB |
- |
