#include <bits/stdc++.h> #pragma GCC optimize("O3,unroll-loops") #pragma GCC target("avx2") //#define int long long #define pii pair<int,int> #define vi vector<int> #define ff first #define ss second #define sp << " " << #define all(x) x.begin(),x.end() #define big(x) ((int)(x.size())) using namespace std; const int MOD = 1e9+7, LIM = 1e6+1, inf = 2e9; /// 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. std::vector<bool> find_positive() { std::vector<bool> answer(N,0); vi unknown; for (int j = 0;j<N;j++) unknown.push_back(j); vector<bool> test(N,0); while (big(unknown)) { test.assign(N,0); vi newunknown; int s = 1; double best = inf; for (int j = 2;j<=big(unknown);j++) { if (P*big(unknown)*__lg(2*j-1)+((big(unknown)+j-1)/j) < best) { best = P*big(unknown)*__lg(2*j-1)+((big(unknown)+j-1)/j); s = j; } } for (int i = 0;i<big(unknown);i+=s) { int R = min(big(unknown)-1,i+s-1); for (int j = i;j<=R;j++) test[unknown[j]] = 1; if (!test_students(test)) continue; int l = i; int r = R; while (l<r) { int m = (l+r) >> 1; for (int j = i;j<=m;j++) if (!answer[unknown[j]]) test[unknown[j]] = 1; for (int j = m+1;j<=R;j++) test[unknown[j]] = 0; if (test_students(test)) r = m; else l = m+1; } answer[unknown[l]] = 1; for (int j = l+1;j<=R;j++) newunknown.push_back(unknown[j]); for (int j = i;j<=R;j++) test[unknown[j]] = 0; } unknown = newunknown; } 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; }

Main.cpp: In function 'bool test_students(std::vector<bool>)':
Main.cpp:38:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   38 |     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:105:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  105 |         scanf(" %c", &verdict);
      |         ~~~~~^~~~~~~~~~~~~~~~~