Submission #1044562

#	Time	Username	Problem	Language	Result	Execution time	Memory
1044562		VahanAbraham	COVID tests (CEOI24_covid)	C++17	13.73 / 100	2712 ms	600 KiB

Main

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <string>
#include <algorithm>
#include <cstring>
#include <cstdio>
#include <sstream>
#include <map>
#include <stack>
#include <set>
#include <queue>
#include <list>
#include <unordered_set>
#include <unordered_map>
#include <math.h>
#include <bitset>
#include <cmath>
#include <vector>
#include <iomanip>
#include <random>
#include <chrono>
#include <cassert>
#include <cassert>
#include <cstdio>
#include <string>
#include <vector>

/// You may use:

using namespace std;


// The number of students
int N;

#define ll long long
#define fr first
#define sc second
#define pb push_back

// 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';
}

int ans[10000];

void rec(int l, int r) {
    vector<bool> v;
    v.resize(N);
    for (int i = 0; i < N; ++i) {
        if (i >= l && i <= r) {
            v[i] = 1;
        }
        else {
            v[i] = 0;
        }
    }
    if (l == r) {
        if (test_students(v) == 0) {
            for (int i = l; i <= r; ++i) {
                ans[i] = -1;
            }
            return;
        }
        return;
    }
    if (test_students(v) == 0) {
        for (int i = l; i <= r; ++i) {
            ans[i] = -1;
        }
        return;
    }
    else {
        int mid = (l + r) / 2;
        rec(l, mid);
        rec(mid + 1, r);
    }
}
/// 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);
    //1111
    int q = 0;
    if (P == 0.001) {
        ++q;
        for (int i = 0; i < N; i += 200) {
            rec(i, min(i + 199,N-1));
        }
    }
    //22
    if (P == 0.005256) {
        ++q;
        for (int i = 0; i < N; i += 180) {
            rec(i, min(i + 179, N-1));
        }
    }
    //3
    if (P == 0.011546) {
        ++q;
        for (int i = 0; i < N; i += 160) {
            rec(i, min(i + 159, N-1));
        }
    }
    //4
    if (P == 0.028545) {
        for (int i = 0; i < N; i += 140) {
            rec(i, min(i + 139, N-1));
        }
    }
    //5
    if (P == 0.039856) {
        ++q;
        for (int i = 0; i < N; i += 100) {
            rec(i, min(i + 99, N-1));
        }
    }
    //6
    if (P == 0.068648) {
        ++q;
        for (int i = 0; i < N; i += 70) {
            rec(i, min(i + 69, N-1));
        }
    }
    //7
    if (P == 0.104571) {
        ++q;
        for (int i = 0; i < N; i += 30) {
            rec(i, min(i + 29, N-1));
        }
    }
    //8
    if (P == 0.158765) {
        ++q;
        for (int i = 0; i < N; i += 20) {
            rec(i, min(i + 19, N-1));
        }
    }
    //9
    if (P == 0.2) {
        ++q;
        for (int i = 0; i < N; i += 8) {
            rec(i, min(i + 7, N-1));
        }
    }
    if (q==0) {
        vector<bool> mn;
        mn.resize(N);
        for (int i = 0; i < N; ++i) {
            mn[i] = 0;
        }
        for (int i = 0; i < N; ++i) {
            mn[i] = 1;
            if (test_students(mn) == 0) {
                ans[i] = -1;
            }
            mn[i] = 0;
        }
    }
    for (int i = 0; i < N; ++i) {
        if (ans[i] == -1) {
            answer[i] = 0;
        }
        else {
            answer[i] = 1;
        }
    }
    for (int i = 0; i < N; ++i) {
        ans[i] = 0;
    }
    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 (stderr)

Main.cpp: In function 'bool test_students(std::vector<bool>)':
Main.cpp:59:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   59 |     scanf(" %c", &answer);
      |     ~~~~~^~~~~~~~~~~~~~~~
Main.cpp: In function 'int main()':
Main.cpp:198:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  198 |     scanf("%d %lf %d", &N, &P, &T);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:214:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  214 |         scanf(" %c", &verdict);
      |         ~~~~~^~~~~~~~~~~~~~~~~

• Subtask 0: 0 / 0
• Subtask 1: 10 / 10
• Subtask 2: 3.729999996 / 90