Submission #1227598

#	Time	Username	Problem	Language	Result	Execution time	Memory
1227598		SpyrosAliv	COVID tests (CEOI24_covid)	C++20	22.36 / 100	892 ms	408 KiB

Main

#include <bits/stdc++.h>
using namespace std;

int N;
double P;

bool test_students(vector<bool> mask) {
    assert(mask.size() == (size_t)N);

    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';
}

vector<bool> binSearch() {
    int n = N;
    vector<bool> curr;
    for (int i = 0; i < n; i++) curr.push_back(false);
    vector<bool> ans;
    for (int i = 0; i < n; i++) ans.push_back(false);
    int idx = 0;
    while (idx < n) {
        int lo = idx;
        int hi = n-1;
        int fin = -1;
        while (lo <= hi) {
            int mid = (lo + hi) / 2;
            for (int i = idx; i <= mid; i++) curr[i] = true;
            if (test_students(curr)) {
                fin = mid;
                hi = mid-1;
            }
            else lo = mid+1;
            for (int i = idx; i <= mid; i++) curr[i] = false;
        }
        if (fin == -1) break;
        idx = fin+1;
        ans[fin] = true;
    }
    return ans;
}

vector<bool> batch(int block) {
    int n = N;
    vector<bool> curr;
    for (int i = 0; i < n; i++) curr.push_back(false);
    vector<bool> ans;
    for (int i = 0; i < n; i++) ans.push_back(false);
    for (int i = 0; i < n; i += block) {
        for (int j = i; j < i + block; j++) {
            if (j >= n) break;
            curr[j] = true;
        }
        int ex = test_students(curr);
        for (int j = i; j < i + block; j++) {
            if (j >= n) break;
            curr[j] = false;
        }
        if (!ex) continue;
        for (int j = i; j < i + block; j++) {
            if (j >= n) break;
            curr[j] = true;
            if (test_students(curr)) {
                ans[j] = true;
            }
            curr[j] = false;
        }
    }
    return ans;
}

vector<bool> find_positive() {
    if (P <= (double)0.02) return binSearch();
    else if (P <= (double)0.03) return batch(20);
    else if (P < (double)0.1) return batch(3);
    else if (P >= (double)0.15) return batch(2);
    return batch(4);
}

void solve() {
    vector<bool> answer = find_positive();
     assert(answer.size() == (size_t)N);

    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; cin >> verdict;
    assert(verdict != 'W');
}

int main() {
    int T;
    scanf("%d %lf %d", &N, &P, &T);

    // You may perform any extra initialization here.
    while (T--) solve();
    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'bool test_students(std::vector<bool>)':
Main.cpp:18:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   18 |     scanf(" %c", &answer);
      |     ~~~~~^~~~~~~~~~~~~~~~
Main.cpp: In function 'int main()':
Main.cpp:104:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  104 |     scanf("%d %lf %d", &N, &P, &T);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 0: 0 / 0
• Subtask 1: 10 / 10
• Subtask 2: 12.36 / 90