| # |
Submission time |
Handle |
Problem |
Language |
Result |
Execution time |
Memory |
| 1051846 |
2024-08-10T10:11:52 Z |
n1k |
COVID tests (CEOI24_covid) |
C++17 |
|
1520 ms |
344 KB |
#include <cassert>
#include <cstdio>
#include <string>
#include <vector>
#include <bits/stdc++.h>
using namespace std;
/// You may use:
// The number of students
int N, T;
// 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';
}
/// 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.
std::vector<bool> find_positive() {
std::vector<bool> answer(N);
vector<int> a(N);
iota(a.begin(), a.end(), 0);
shuffle(a.begin(), a.end(), mt19937{std::random_device{}()});
double E = N * P;
int take = T == 1 ? 1 : max(1., (1./(E / N)) * 2./3);
if(P==0.2){
take = 4;
}if(P==0.104571){
take = 8;
}if(P==0.158765){
take = 4;
}if(P==0.068648){
take = 8;
}if(P==0.039856){
take = 16;
}
//int take = T == 1 ? 1 : max(1., round((1./(max(1., E) / N)) * 2./3));
for(int i=0, r=0; i<N; r++){
//take = T == 1 ? 1 : max(1., round((1./(max(1., E) / N)) * 2./3));
//cerr << E << " " << take << endl;
vector<bool> mask(N);
for(int j=0; j<take and i+j<N; j++){
mask[i+j] = 1;
}
if(test_students(mask)){
if(P==0.2){
int j;
for(j=0; j<take and i+j<N; j++){
mask.assign(N, 0);
mask[i+j] = 1;
if(test_students(mask)){
break;
}
}
answer[i+j]=1;
i=i+j+1;
}else{
int lb = i, rb = min(i + take - 1, N-1);
while(lb<rb){
int mb = (lb+rb)/2;
mask.assign(N, 0);
for(int j=lb; j<=mb; j++) mask[j]=1;
if(test_students(mask)){
rb = mb;
}else{
lb = mb + 1;
}
}
answer[lb]=1;
i = lb + 1;
}
}else{
i += take;
}
}
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
Main.cpp: In function 'bool test_students(std::vector<bool>)':
Main.cpp:32:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
32 | scanf(" %c", &answer);
| ~~~~~^~~~~~~~~~~~~~~~
Main.cpp: In function 'int main()':
Main.cpp:107:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
107 | scanf("%d %lf %d", &N, &P, &T);
| ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:123:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
123 | scanf(" %c", &verdict);
| ~~~~~^~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
344 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
5 ms |
344 KB |
Output is correct |
| 2 |
Correct |
7 ms |
344 KB |
Output is correct |
| 3 |
Correct |
6 ms |
344 KB |
Output is correct |
| 4 |
Correct |
5 ms |
344 KB |
Output is correct |
| 5 |
Correct |
6 ms |
344 KB |
Output is correct |
| 6 |
Correct |
7 ms |
344 KB |
Output is correct |
| 7 |
Correct |
5 ms |
344 KB |
Output is correct |
| 8 |
Correct |
5 ms |
344 KB |
Output is correct |
| 9 |
Correct |
5 ms |
344 KB |
Output is correct |
| 10 |
Correct |
5 ms |
344 KB |
Output is correct |
| 11 |
Correct |
7 ms |
344 KB |
Output is correct |
| 12 |
Correct |
6 ms |
344 KB |
Output is correct |
| 13 |
Correct |
6 ms |
344 KB |
Output is correct |
| 14 |
Correct |
5 ms |
344 KB |
Output is correct |
| 15 |
Correct |
9 ms |
344 KB |
Output is correct |
| 16 |
Correct |
7 ms |
344 KB |
Output is correct |
| 17 |
Correct |
6 ms |
344 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
21 ms |
344 KB |
Output is correct (P=0.001, F=15.1, Q=10.9) -> 90.00 points |
| 2 |
Correct |
106 ms |
344 KB |
Output is correct (P=0.005256, F=51.1, Q=46.6) -> 90.00 points |
| 3 |
Correct |
185 ms |
344 KB |
Output is correct (P=0.011546, F=94.9, Q=91.4) -> 90.00 points |
| 4 |
Correct |
388 ms |
344 KB |
Output is correct (P=0.028545, F=191.5, Q=190.8) -> 90.00 points |
| 5 |
Correct |
478 ms |
344 KB |
Output is correct (P=0.039856, F=246.3, Q=244.0) -> 90.00 points |
| 6 |
Correct |
719 ms |
344 KB |
Output is correct (P=0.068648, F=366.2, Q=365.8) -> 90.00 points |
| 7 |
Correct |
978 ms |
344 KB |
Output is correct (P=0.104571, F=490.3, Q=493.5) -> 87.71 points |
| 8 |
Correct |
1213 ms |
344 KB |
Output is correct (P=0.158765, F=639.1, Q=633.1) -> 90.00 points |
| 9 |
Correct |
1520 ms |
344 KB |
Output is correct (P=0.2, F=731.4, Q=786.1) -> 69.28 points |
