Submission #1108862

#	Time	Username	Problem	Language	Result	Execution time	Memory
1108862		8pete8	COVID tests (CEOI24_covid)	C++17	10 / 100	5238 ms	336 KiB

Main

#include <cassert>
#include <cstdio>
#include <string>
#include <vector>
#include<iostream>
#include<stack>
#include<map>
#include<vector>
#include<string>
#include<cassert>
#include<unordered_map>
#include <queue>
#include <cstdint>
#include<cstring>
#include<limits.h>
#include<cmath>
#include<set>
#include<algorithm>
#include <iomanip>
#include<numeric>
#include<bitset>
using namespace std;
#define ll long long
#define f first
#define s second
#define pii pair<int,int>
#define ppii pair<int,pii>
#define vi vector<int>
#define pb push_back
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define F(n) for(int i=0;i<n;i++)
#define lb lower_bound
#define ub upper_bound
#define fastio ios::sync_with_stdio(false);cin.tie(NULL);
#pragma GCC optimize ("03,unroll-lopps")
/// You may use:

// 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 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';
}

int T;
/// 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.
vector<bool> find_positive() {
    std::vector<bool> answer(N,0);
    if(T==1){
        for(int i=0;i<N;i++){
            vector<bool>qry(N,0);
            qry[i]=1;
            answer[i]=test_students(qry);
        }
        return answer;
    }
    else{
        int l=0,r=N-1;
        vector<bool>qry(N,0);
        while(1){
            r=N-1;
            int pos=N;
            while(l<=r){
                int mid=l+(r-l)/2;
                for(int j=l;j<=mid;j++)qry[j]=1;
                if(test_students(qry)){
                    for(int j=l;j<=mid;j++)qry[j]=0;
                    pos=min(pos,mid),r=mid-1;
                }
                else {
                    for(int j=l;j<=mid;j++)qry[j]=0;
                    l=mid+1;
                }
            }
            if(pos==N)break;
            l=pos+1;
            answer[pos]=1;
        }
        return answer;
    }
}

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

Main.cpp:36:40: warning: bad option '-funroll-lopps' to pragma 'optimize' [-Wpragmas]
   36 | #pragma GCC optimize ("03,unroll-lopps")
      |                                        ^
Main.cpp:49:42: warning: bad option '-funroll-lopps' to attribute 'optimize' [-Wattributes]
   49 | bool test_students(std::vector<bool> mask) {
      |                                          ^
Main.cpp:71:28: warning: bad option '-funroll-lopps' to attribute 'optimize' [-Wattributes]
   71 | vector<bool> find_positive() {
      |                            ^
Main.cpp:107:10: warning: bad option '-funroll-lopps' to attribute 'optimize' [-Wattributes]
  107 | int main() {
      |          ^
Main.cpp: In function 'bool test_students(std::vector<bool>)':
Main.cpp:60:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   60 |     scanf(" %c", &answer);
      |     ~~~~~^~~~~~~~~~~~~~~~
Main.cpp: In function 'int main()':
Main.cpp:109:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  109 |     scanf("%d %lf %d", &N, &P, &T);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:121:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  121 |         scanf(" %c", &verdict);
      |         ~~~~~^~~~~~~~~~~~~~~~~

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