oj.uz

Submission #1069073

# Submission time Handle Problem Language Result Execution time Memory
1069073 2024-08-21T15:37:11 Z huutuan COVID tests (CEOI24_covid) C++14
0 / 100
 3934 ms 344 KB 
#include <cassert>
#include <cstdio>
#include <string>
#include <vector>

#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.
int test_students(std::vector<int> 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<int> find_positive() {
   vector<int> ans(N);
   vector<int> order(N);
   mt19937 rng(69420);
   iota(order.begin(), order.end(), 0);
   shuffle(order.begin(), order.end(), rng);
   auto query=[&](int l, int r) -> int {
      if (l>r) return 0;
      vector<int> test(N);
      for (int i=l; i<=r; ++i) test[order[i]]=1;
      return test_students(test);
   };
   int st=0;
   while (query(st, N-1)){
      int l=st, r=N-2;
      while (l<=r){
         int mid=(l+r)>>1;
         if (query(st, mid)) r=mid-1;
         else l=mid+1;
      }
      ans[order[l]]=1;
      st=l+1;
   }
   return ans;
}

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<int> 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 'int test_students(std::vector<int>)':
Main.cpp:33:9: 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:71:9: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   71 |    scanf("%d %lf %d", &N, &P, &T);
      |    ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:87:12: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   87 |       scanf(" %c", &verdict);
      |       ~~~~~^~~~~~~~~~~~~~~~~

Subtask #0
0.0 / 0.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 344 KB Output is correct

Subtask #1
0.0 / 10.0

# Verdict Execution time Memory Grader output
1 Incorrect 61 ms 340 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #2
0.0 / 90.0

# Verdict Execution time Memory Grader output
1 Correct 32 ms 344 KB Output is correct (P=0.001, F=15.1, Q=10.8) -> 90.00 points
2 Correct 126 ms 344 KB Output is correct (P=0.005256, F=51.1, Q=52.8) -> 79.43 points
3 Correct 247 ms 344 KB Output is correct (P=0.011546, F=94.9, Q=114.7) -> 49.06 points
4 Correct 664 ms 344 KB Output is correct (P=0.028545, F=191.5, Q=277.9) -> 32.09 points
5 Correct 886 ms 344 KB Output is correct (P=0.039856, F=246.3, Q=387.9) -> 27.28 points
6 Correct 1546 ms 344 KB Output is correct (P=0.068648, F=366.2, Q=664.3) -> 21.15 points
7 Correct 2460 ms 344 KB Output is correct (P=0.104571, F=490.3, Q=1002.3) -> 17.38 points
8 Correct 3822 ms 340 KB Output is correct (P=0.158765, F=639.1, Q=1495.8) -> 14.15 points
9 Execution timed out 3934 ms 344 KB Time limit exceeded (wall clock)
10 Halted 0 ms 0 KB -