oj.uz

Submission #1026655

# Submission time Handle Problem Language Result Execution time Memory
1026655 2024-07-18T09:04:12 Z 김은성(#10945) COVID tests (CEOI24_covid) C++17
40.11 / 100
 2287 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.
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.
vector<bool> answer, query;
void solve(int lo, int hi){
    int i;
    for(i=lo; i<=hi; i++)
        query[i] = 1;
    bool x = test_students(query);
    for(i=lo; i<=hi; i++)
        query[i] = 0;
    if(!x)
        return;
    int n = hi-lo+1, D;
    if(P==1)
        D = n+2;
    else{
    double pos = P / (1 - pow(1-P, n));
    if(pos >= 1) D=n+2;
    else
        D = -(int)((double)n * (double)(log(1-pos) * 1.2));
    if(D <= 1)
        D = 2;
        }
    if(lo==hi)
        answer[lo] = 1;
    //printf("pos=%f D=%d\n", pos, D);
    else{
        if(hi-lo < D){
            for(int i=lo; i<=hi; i++)
                solve(i, i);
        }
        else{
            int i, x = lo-1;
            for(i=1; i<=D; i++){
                solve(x+1, (lo*(D-i) + hi*i)/D);
                x = (lo*(D-i) + hi*i)/D;
            }
        }
    }
}
std::vector<bool> find_positive() {
    answer.resize(N);
    query.resize(N);
    int i;
    for(i=0; i<N; i++)
        answer[i]= query[i] = 0;
    solve(0, N-1);
    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

Main.cpp: In function 'bool test_students(std::vector<bool>)':
Main.cpp:31:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   31 |     scanf(" %c", &answer);
      |     ~~~~~^~~~~~~~~~~~~~~~
Main.cpp: In function 'int main()':
Main.cpp:91:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   91 |     scanf("%d %lf %d", &N, &P, &T);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:107:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  107 |         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 6 ms 344 KB Output is correct
2 Correct 8 ms 344 KB Output is correct
3 Correct 7 ms 344 KB Output is correct
4 Correct 9 ms 344 KB Output is correct
5 Correct 6 ms 344 KB Output is correct
6 Correct 5 ms 344 KB Output is correct
7 Correct 5 ms 344 KB Output is correct
8 Correct 9 ms 344 KB Output is correct
9 Correct 6 ms 344 KB Output is correct
10 Correct 7 ms 340 KB Output is correct
11 Correct 9 ms 344 KB Output is correct
12 Correct 6 ms 344 KB Output is correct
13 Correct 7 ms 344 KB Output is correct
14 Correct 7 ms 344 KB Output is correct
15 Correct 9 ms 344 KB Output is correct
16 Correct 8 ms 344 KB Output is correct
17 Correct 0 ms 344 KB Output is correct

Subtask #2
30.110000004 / 90.0

# Verdict Execution time Memory Grader output
1 Correct 51 ms 344 KB Output is correct (P=0.001, F=15.1, Q=17.8) -> 52.47 points
2 Correct 188 ms 344 KB Output is correct (P=0.005256, F=51.1, Q=75.7) -> 30.76 points
3 Correct 320 ms 344 KB Output is correct (P=0.011546, F=94.9, Q=142.1) -> 30.11 points
4 Correct 698 ms 340 KB Output is correct (P=0.028545, F=191.5, Q=279.5) -> 31.71 points
5 Correct 949 ms 344 KB Output is correct (P=0.039856, F=246.3, Q=357.0) -> 32.17 points
6 Correct 1353 ms 344 KB Output is correct (P=0.068648, F=366.2, Q=513.2) -> 34.54 points
7 Correct 1564 ms 344 KB Output is correct (P=0.104571, F=490.3, Q=651.1) -> 38.93 points
8 Correct 1812 ms 340 KB Output is correct (P=0.158765, F=639.1, Q=820.4) -> 42.16 points
9 Correct 2287 ms 344 KB Output is correct (P=0.2, F=731.4, Q=906.3) -> 46.00 points