답안 #1078248

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
1078248 2024-08-27T14:30:41 Z anton COVID tests (CEOI24_covid) C++17
100 / 100
2067 ms 11344 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][1001];
double expected_turns[1001][1001];
std::vector<bool> find_positive() {
    std::vector<bool> answer(N);

    int total = N;
    int pref = 0;
    while(total>0){
        if(split_len[total][pref] == 0){
            answer[N-total] = true;
            total --;
            pref = 0;
        }
        else{
            int len = split_len[total][pref];
            bool is_one = test_inter(N-total, N-total+len-1);
            if(is_one){
                pref = len;
            }
            else{
                total-=len;

                if(len<pref){
                    pref-=len;
                }
            }
        }
    }
    
    return answer;
}
double memo[1001];

double mpow(int deg){
    return memo[deg];
}
double P_1(int len){
    return 1.-mpow(len);
}
double P_none(int len){
    return mpow(len);
}

void chmax(int total, int pref, int test_len, double expected){
    if(expected_turns[total][pref]>expected){
        split_len[total][pref] = test_len;
        expected_turns[total][pref] = expected;
    }
}
int main() {
    int T;
    scanf("%d %lf %d", &N, &P, &T);

    memo[0] =1.;
    for(int i =1; i<1001; i++){
        memo[i] = memo[i-1] * (1.-P);
    }
    // You may perform any extra initialization here.
    
    for(int total = 0; total<=N; total++){
        for(int pref=  0; pref<=total; pref++){
            expected_turns[total][pref] = 1e18;
        }
    }

    expected_turns[0][0] = 0.;
    for(int total = 1; total<=N; total++){
        for(int pref=  1; pref<=total; pref++){
            if(pref==1){
                chmax(total, pref, 0, expected_turns[total-1][0]);
            }
            else{
                for(int test_len = 1; test_len<pref; test_len++){
                    double p_cur = P_1(pref);
                    double P_left = P_1(test_len)/p_cur;
                    double expected = P_left * expected_turns[total][test_len] +(1-P_left) * expected_turns[total-test_len][pref-test_len] + 1.;
                    chmax(total, pref, test_len, expected);
                }
            }
        }
        for(int test_len = 1; test_len<=total; test_len++){
            double expected=  P_1(test_len) * expected_turns[total][test_len] + P_none(test_len) * expected_turns[total-test_len][0] + 1.;
            chmax(total, 0, test_len, expected);
        }
    }
    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:103:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  103 |     scanf("%d %lf %d", &N, &P, &T);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:149:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  149 |         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 281 ms 11048 KB Output is correct
2 Correct 281 ms 11088 KB Output is correct
3 Correct 292 ms 11088 KB Output is correct
4 Correct 281 ms 11164 KB Output is correct
5 Correct 305 ms 11088 KB Output is correct
6 Correct 294 ms 11088 KB Output is correct
7 Correct 276 ms 11084 KB Output is correct
8 Correct 296 ms 11000 KB Output is correct
9 Correct 289 ms 11092 KB Output is correct
10 Correct 286 ms 11080 KB Output is correct
11 Correct 285 ms 11008 KB Output is correct
12 Correct 289 ms 11200 KB Output is correct
13 Correct 280 ms 11088 KB Output is correct
14 Correct 282 ms 11340 KB Output is correct
15 Correct 286 ms 10996 KB Output is correct
16 Correct 304 ms 11000 KB Output is correct
17 Correct 285 ms 11088 KB Output is correct
# 결과 실행 시간 메모리 Grader output
1 Correct 326 ms 11088 KB Output is correct (P=0.001, F=15.1, Q=10.8) -> 90.00 points
2 Correct 415 ms 11344 KB Output is correct (P=0.005256, F=51.1, Q=46.3) -> 90.00 points
3 Correct 549 ms 11088 KB Output is correct (P=0.011546, F=94.9, Q=90.5) -> 90.00 points
4 Correct 808 ms 11088 KB Output is correct (P=0.028545, F=191.5, Q=187.7) -> 90.00 points
5 Correct 909 ms 11088 KB Output is correct (P=0.039856, F=246.3, Q=243.7) -> 90.00 points
6 Correct 1176 ms 11088 KB Output is correct (P=0.068648, F=366.2, Q=364.2) -> 90.00 points
7 Correct 1528 ms 11088 KB Output is correct (P=0.104571, F=490.3, Q=488.2) -> 90.00 points
8 Correct 1775 ms 11220 KB Output is correct (P=0.158765, F=639.1, Q=633.1) -> 90.00 points
9 Correct 2067 ms 11044 KB Output is correct (P=0.2, F=731.4, Q=729.3) -> 90.00 points