답안 #1076788

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
1076788 2024-08-26T16:32:54 Z anton COVID tests (CEOI24_covid) C++17
0 / 100
4127 ms 440 KB
#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;

int group_sz =1;
// 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.
bool test_single(int u){
    vector<bool> mask(N, false);
    mask[u] = true;
    return test_students(mask);
}

bool test_inter(int l, int r){
    vector<bool> mask(N, false);
    for(int i = l; i<=r; i++){
        mask[i] = true;
    }
    return test_students(mask);
}
void find_positive(int l, int r, vector<bool>& res){
    if(l==r){
        res[l] = true;
        return;
    }
    int mid = (l+r)/2;
    if(test_inter(l, mid)){
        find_positive(l, mid, res);
    }
    if(test_inter(mid+1, r)){
        find_positive(mid+1, r, res);
    }
}

int opti_split[1001];

void do_split(int l, int r,vector<bool>& ans){
    if(l==r){
        ans[l] = true;
        return;
    }
    int opti_len = opti_split[r-l+1];
    if(test_inter(l, l+opti_len-1)){
        do_split(l, l+opti_len-1, ans);
        if(test_inter(l+opti_len, r)){
            do_split(l+opti_len, r, ans);
        }
    }
    else{
        do_split(l+opti_len, r, ans);
    }
}
std::vector<bool> find_positive() {
    std::vector<bool> answer(N);

   if(test_inter(0, N-1)){
    do_split(0, N-1, answer);
   }
    
    /*for(int i = 0; i<N; i+=group_sz){
        vector<bool>cur_mask (N, false);

        vector<int> order;
        for(int j = i; j<min(i+group_sz, N); j++){
            cur_mask[j] = true;
        }    
        
        if(test_students(cur_mask)){
            bool found = false;
            for(int j = i; j<min(i+group_sz, N); j++){
                answer[j] = test_single(j);
                cur_mask[j] = false;
                if(answer[j] && j<min(i+group_sz, N)-1){
                    if(!test_students(cur_mask)){
                        break;
                    }
                }
            }
        }
    }*/


    return answer;
}

int get_sz(double p, double target){
    int res = 1;
    double cur_p = p;
    while(cur_p>0.5){
        res ++;
        cur_p*=p;
    }
    return res;
}


double at_least_1(int len){
    return pow(1.-P, len);
}
int main() {
    int T;
    scanf("%d %lf %d", &N, &P, &T);

    // You may perform any extra initialization here.
    group_sz= min(max(get_sz((1.-P), 0.5), 1), N/2);

    vector<double> expected_turns(N+1, 1e18);
    for(int i = 1; i<=N; i++){
        if(i==1){
            expected_turns[i] = 0.;
        }
        for(int j = 1; j<=(i/2); j++){
            double other = 1.+at_least_1(j)* (expected_turns[j] + 1.+ at_least_1(i-j)* expected_turns[i-j]) + (1.-at_least_1(j)) * expected_turns[i-j];
            if(other< expected_turns[i]){
                opti_split[i] = j;
            }
        }
    }
    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:28:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   28 |     scanf(" %c", &answer);
      |     ~~~~~^~~~~~~~~~~~~~~~
Main.cpp: In function 'int main()':
Main.cpp:132:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  132 |     scanf("%d %lf %d", &N, &P, &T);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:161:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  161 |         scanf(" %c", &verdict);
      |         ~~~~~^~~~~~~~~~~~~~~~~
# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 344 KB Output is correct
# 결과 실행 시간 메모리 Grader output
1 Correct 25 ms 440 KB Output is correct
2 Correct 24 ms 344 KB Output is correct
3 Correct 29 ms 344 KB Output is correct
4 Correct 23 ms 344 KB Output is correct
5 Correct 28 ms 344 KB Output is correct
6 Correct 25 ms 344 KB Output is correct
7 Correct 20 ms 344 KB Output is correct
8 Correct 19 ms 344 KB Output is correct
9 Correct 23 ms 344 KB Output is correct
10 Correct 22 ms 344 KB Output is correct
11 Correct 19 ms 344 KB Output is correct
12 Correct 20 ms 344 KB Output is correct
13 Correct 20 ms 344 KB Output is correct
14 Correct 19 ms 344 KB Output is correct
15 Correct 22 ms 344 KB Output is correct
16 Execution timed out 4127 ms 344 KB Time limit exceeded (wall clock)
17 Halted 0 ms 0 KB -
# 결과 실행 시간 메모리 Grader output
1 Incorrect 894 ms 344 KB Incorrect
2 Halted 0 ms 0 KB -