oj.uz

Submission #1071981

# Submission time Handle Problem Language Result Execution time Memory
1071981 2024-08-23T12:58:30 Z _8_8_ COVID tests (CEOI24_covid) C++17
95.6 / 100
 1751 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)(0.61 / P);
    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 14 ms 344 KB Output is correct
3 Correct 11 ms 344 KB Output is correct
4 Correct 13 ms 344 KB Output is correct
5 Correct 13 ms 344 KB Output is correct
6 Correct 11 ms 344 KB Output is correct
7 Correct 10 ms 344 KB Output is correct
8 Correct 9 ms 344 KB Output is correct
9 Correct 11 ms 344 KB Output is correct
10 Correct 4 ms 344 KB Output is correct
11 Correct 8 ms 344 KB Output is correct
12 Correct 9 ms 344 KB Output is correct
13 Correct 10 ms 344 KB Output is correct
14 Correct 13 ms 344 KB Output is correct
15 Correct 9 ms 340 KB Output is correct
16 Correct 13 ms 344 KB Output is correct
17 Correct 0 ms 344 KB Output is correct

Subtask #2
85.599999999 / 90.0

# Verdict Execution time Memory Grader output
1 Correct 22 ms 344 KB Output is correct (P=0.001, F=15.1, Q=11.3) -> 90.00 points
2 Correct 123 ms 344 KB Output is correct (P=0.005256, F=51.1, Q=48.1) -> 90.00 points
3 Correct 231 ms 344 KB Output is correct (P=0.011546, F=94.9, Q=92.8) -> 90.00 points
4 Correct 469 ms 344 KB Output is correct (P=0.028545, F=191.5, Q=190.5) -> 90.00 points
5 Correct 583 ms 344 KB Output is correct (P=0.039856, F=246.3, Q=245.2) -> 90.00 points
6 Correct 838 ms 344 KB Output is correct (P=0.068648, F=366.2, Q=368.0) -> 88.26 points
7 Correct 1163 ms 344 KB Output is correct (P=0.104571, F=490.3, Q=488.3) -> 90.00 points
8 Correct 1494 ms 344 KB Output is correct (P=0.158765, F=639.1, Q=633.1) -> 90.00 points
9 Correct 1751 ms 344 KB Output is correct (P=0.2, F=731.4, Q=740.8) -> 85.60 points