답안 #1076832

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
1076832 2024-08-26T17:02:13 Z anton COVID tests (CEOI24_covid) C++17
45.72 / 100
7000 ms 596 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);
}

int split_len[1001];

void do_split(int l, int r,vector<bool>& ans){
    if(l==r){
        ans[l] = true;
        return;
    }
    int opti_len = split_len[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 1.-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.;
        }
        else{
            for(int j = 1; j<i; j++){
                double total = at_least_1(j) * pow(1.-P, i-j) + at_least_1(i-j) * pow(1.-P, j) +at_least_1(j)*at_least_1(i-j);
                double prop_j = (at_least_1(j) * pow(1.-P, i-j) + at_least_1(j)*at_least_1(i-j))/total;
                prop_j *= 1.05;
                double prop_i = 1.-prop_j;
                double other = 1.+(prop_j)* (expected_turns[j] + 1.+ at_least_1(i-j)* expected_turns[i-j]) + (prop_i) * expected_turns[i-j];
                if(other< expected_turns[i]){
                    split_len[i] = j;
                    expected_turns[i]= other;
                }
            
            }
        }
    }
    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:118:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  118 |     scanf("%d %lf %d", &N, &P, &T);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:155:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  155 |         scanf(" %c", &verdict);
      |         ~~~~~^~~~~~~~~~~~~~~~~
# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 340 KB Output is correct
# 결과 실행 시간 메모리 Grader output
1 Correct 144 ms 412 KB Output is correct
2 Correct 119 ms 344 KB Output is correct
3 Correct 165 ms 344 KB Output is correct
4 Correct 136 ms 344 KB Output is correct
5 Correct 176 ms 416 KB Output is correct
6 Correct 152 ms 344 KB Output is correct
7 Correct 134 ms 420 KB Output is correct
8 Correct 108 ms 344 KB Output is correct
9 Correct 109 ms 344 KB Output is correct
10 Correct 87 ms 596 KB Output is correct
11 Correct 90 ms 344 KB Output is correct
12 Correct 91 ms 344 KB Output is correct
13 Correct 99 ms 344 KB Output is correct
14 Correct 99 ms 416 KB Output is correct
15 Correct 94 ms 344 KB Output is correct
16 Correct 80 ms 596 KB Output is correct
17 Execution timed out 7032 ms 344 KB Time limit exceeded
18 Halted 0 ms 0 KB -
# 결과 실행 시간 메모리 Grader output
1 Correct 128 ms 344 KB Output is correct (P=0.001, F=15.1, Q=13.2) -> 90.00 points
2 Correct 249 ms 344 KB Output is correct (P=0.005256, F=51.1, Q=58.8) -> 56.15 points
3 Correct 323 ms 592 KB Output is correct (P=0.011546, F=94.9, Q=113.7) -> 50.21 points
4 Correct 607 ms 596 KB Output is correct (P=0.028545, F=191.5, Q=233.4) -> 47.99 points
5 Correct 822 ms 344 KB Output is correct (P=0.039856, F=246.3, Q=299.7) -> 48.20 points
6 Correct 1172 ms 344 KB Output is correct (P=0.068648, F=366.2, Q=446.9) -> 47.83 points
7 Correct 1561 ms 344 KB Output is correct (P=0.104571, F=490.3, Q=595.4) -> 48.45 points
8 Correct 2015 ms 344 KB Output is correct (P=0.158765, F=639.1, Q=778.3) -> 48.10 points
9 Correct 2290 ms 344 KB Output is correct (P=0.2, F=731.4, Q=908.5) -> 45.72 points