oj.uz

Submission #1069057

# Submission time Handle Problem Language Result Execution time Memory
1069057 2024-08-21T15:22:11 Z huutuan COVID tests (CEOI24_covid) C++14
36.95 / 100
 2645 ms 568 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);
   auto query=[&](int l, int r) -> int {
      vector<int> test(N);
      fill(test.begin()+l, test.begin()+r+1, 1);
      return test_students(test);
   };
   auto solve=[&](auto &&self, int l, int r) -> void {
      if (!query(l, r)) return;
      if (l==r){
         ans[l]=1;
         return;
      }
      int mid=(l+r)>>1;
      self(self, l, mid);
      self(self, mid+1, r);
   };
   solve(solve, 0, N-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:66:9: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   66 |    scanf("%d %lf %d", &N, &P, &T);
      |    ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:82:12: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   82 |       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
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 344 KB Output is correct
2 Correct 14 ms 344 KB Output is correct
3 Correct 11 ms 344 KB Output is correct
4 Correct 10 ms 344 KB Output is correct
5 Correct 11 ms 344 KB Output is correct
6 Correct 16 ms 344 KB Output is correct
7 Correct 16 ms 344 KB Output is correct
8 Correct 17 ms 568 KB Output is correct
9 Correct 13 ms 344 KB Output is correct
10 Correct 6 ms 344 KB Output is correct
11 Correct 9 ms 344 KB Output is correct
12 Correct 9 ms 344 KB Output is correct
13 Correct 9 ms 344 KB Output is correct
14 Correct 9 ms 344 KB Output is correct
15 Correct 10 ms 344 KB Output is correct
16 Correct 18 ms 344 KB Output is correct
17 Correct 0 ms 344 KB Output is correct

Subtask #2
26.949999996 / 90.0

# Verdict Execution time Memory Grader output
1 Correct 40 ms 344 KB Output is correct (P=0.001, F=15.1, Q=17.8) -> 52.47 points
2 Correct 184 ms 344 KB Output is correct (P=0.005256, F=51.1, Q=78.0) -> 28.98 points
3 Correct 350 ms 344 KB Output is correct (P=0.011546, F=94.9, Q=150.0) -> 27.09 points
4 Correct 718 ms 344 KB Output is correct (P=0.028545, F=191.5, Q=303.5) -> 26.95 points
5 Correct 905 ms 344 KB Output is correct (P=0.039856, F=246.3, Q=388.5) -> 27.20 points
6 Correct 1395 ms 344 KB Output is correct (P=0.068648, F=366.2, Q=569.4) -> 27.95 points
7 Correct 1771 ms 344 KB Output is correct (P=0.104571, F=490.3, Q=751.4) -> 28.75 points
8 Correct 2406 ms 344 KB Output is correct (P=0.158765, F=639.1, Q=967.6) -> 29.45 points
9 Correct 2645 ms 344 KB Output is correct (P=0.2, F=731.4, Q=1112.6) -> 29.18 points