oj.uz

Submission #1071957

# Submission time Handle Problem Language Result Execution time Memory
1071957 2024-08-23T12:45:04 Z _8_8_ COVID tests (CEOI24_covid) C++17
89.21 / 100
 1788 ms 344 KB 
#include <cassert>
#include <cstdio>
#include <string>
#include <vector>
#include <bits/stdc++.h>
using namespace std;;
/// You may use:
string s;
// 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 loc = 0;
bool test_students(std::vector<bool> mask) {
    if(loc) {
        bool ans = false;
        for(int i = 0; i < N; i++) {
            if(mask[i] && s[i] == '1') {
                ans = 1;
            }
        }
        return ans;
    }
    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:

mt19937 rng(123321);
// 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 as(int l,int r) {
    vector<bool> ask(N,0);
    for(int i = l;i <= min(N - 1,r);i++) {
        ask[i] = 1;
    }
    return test_students(ask);
}
std::vector<bool> find_positive() {
    vector<bool> answer(N),ask(N,0);
    function<void(int,int)>go1 = [&](int l,int r) {
        if(l == r) {
            answer[l] = 1;
            return;
        }
        int mid = (l + r) >> 1;
        if(as(l,mid)) {
            go1(l,mid);
        }
        if(as(mid+1,r)) go1(mid+1,r);
    };
    function<int(int,int)>go = [&](int l,int r) {
        if(l == r) {
            answer[l] = 1;
            return l;
        }
        int mid = (l + l + r) / 3;
        if(as(l,mid)) {
            return go(l,mid);
        }
        return go(mid+1,r);
    };
    auto solve = [&](int b) {
        int i = 0;
        while(i < N) {
            int r = min(N - 1,i + b);
            if(as(i,r)) {
                go1(i,r);
            }
            i = r + 1;
        }
    };
    if(P == 0) {
        return answer;
    }
    if(P > 0.2){
        solve(70);
        return answer;
    } 
    int b = (int)(0.5 / P) - 1;
    int i = 0;
    while(i < N) {
        int r = min(i + b,N - 1);
        if(as(i,r)) {
            i = go(i,r)+1;
        } else {
            i = r + 1;
        }
    }
    return answer;
}

int main() {
    int T;
    scanf("%d %lf %d", &N, &P, &T);
    if(loc) cin >> s;
    // 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:38:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   38 |     scanf(" %c", &answer);
      |     ~~~~~^~~~~~~~~~~~~~~~
Main.cpp: In function 'int main()':
Main.cpp:112:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  112 |     scanf("%d %lf %d", &N, &P, &T);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:128:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  128 |         scanf(" %c", &verdict);
      |         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #0
0.0 / 0.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 344 KB Output is correct
2 Correct 13 ms 344 KB Output is correct
3 Correct 12 ms 344 KB Output is correct
4 Correct 11 ms 344 KB Output is correct
5 Correct 15 ms 344 KB Output is correct
6 Correct 12 ms 344 KB Output is correct
7 Correct 14 ms 344 KB Output is correct
8 Correct 12 ms 344 KB Output is correct
9 Correct 10 ms 340 KB Output is correct
10 Correct 4 ms 344 KB Output is correct
11 Correct 12 ms 344 KB Output is correct
12 Correct 11 ms 344 KB Output is correct
13 Correct 11 ms 344 KB Output is correct
14 Correct 11 ms 344 KB Output is correct
15 Correct 9 ms 344 KB Output is correct
16 Correct 17 ms 344 KB Output is correct
17 Correct 0 ms 344 KB Output is correct

Subtask #2
79.209999999 / 90.0

# Verdict Execution time Memory Grader output
1 Correct 33 ms 344 KB Output is correct (P=0.001, F=15.1, Q=11.3) -> 90.00 points
2 Correct 146 ms 344 KB Output is correct (P=0.005256, F=51.1, Q=48.3) -> 90.00 points
3 Correct 241 ms 344 KB Output is correct (P=0.011546, F=94.9, Q=93.4) -> 90.00 points
4 Correct 446 ms 344 KB Output is correct (P=0.028545, F=191.5, Q=192.0) -> 89.07 points
5 Correct 581 ms 344 KB Output is correct (P=0.039856, F=246.3, Q=250.1) -> 84.77 points
6 Correct 830 ms 344 KB Output is correct (P=0.068648, F=366.2, Q=370.6) -> 85.87 points
7 Correct 1171 ms 344 KB Output is correct (P=0.104571, F=490.3, Q=502.9) -> 81.61 points
8 Correct 1507 ms 344 KB Output is correct (P=0.158765, F=639.1, Q=645.7) -> 86.43 points
9 Correct 1788 ms 344 KB Output is correct (P=0.2, F=731.4, Q=756.3) -> 79.21 points