| # |
Submission time |
Handle |
Problem |
Language |
Result |
Execution time |
Memory |
| 1076875 |
2024-08-26T17:37:29 Z |
anton |
COVID tests (CEOI24_covid) |
C++17 |
|
5715 ms |
43152 KB |
#include<bits/stdc++.h>
using namespace std;
/// You may use:
// The number of students
int N;
// The probability any given student is positive
double P;
int group_sz =1;
// 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.
bool test_single(int u){
vector<bool> mask(N, false);
mask[u] = true;
return test_students(mask);
}
bool test_inter(int l, int r){
vector<bool> mask(N, false);
for(int i = l; i<=r; i++){
mask[i] = true;
}
return test_students(mask);
}
int split_len[1001];
void do_split(int l, int r,vector<bool>& ans){
if(l==r){
ans[l] = true;
return;
}
int opti_len = split_len[r-l+1];
if(test_inter(l, l+opti_len-1)){
do_split(l, l+opti_len-1, ans);
if(test_inter(l+opti_len, r)){
do_split(l+opti_len, r, ans);
}
}
else{
do_split(l+opti_len, r, ans);
}
}
int find_first(int l, int r){
if(l == r){
return l;
}
int opti_len = split_len[r-l+1];
if(test_inter(l, l+opti_len-1)){
find_first(l, l+opti_len-1);
}
else{
find_first(l+opti_len, r);
}
}
std::vector<bool> find_positive() {
std::vector<bool> answer(N);
int l = 0;
while(l<N && test_inter(l, N-1)){
l = find_first(l, N-1);
answer[l] = true;
l++;
}
/*for(int i = 0; i<N; i+=group_sz){
vector<bool>cur_mask (N, false);
vector<int> order;
for(int j = i; j<min(i+group_sz, N); j++){
cur_mask[j] = true;
}
if(test_students(cur_mask)){
bool found = false;
for(int j = i; j<min(i+group_sz, N); j++){
answer[j] = test_single(j);
cur_mask[j] = false;
if(answer[j] && j<min(i+group_sz, N)-1){
if(!test_students(cur_mask)){
break;
}
}
}
}
}*/
return answer;
}
int get_sz(double p, double target){
int res = 1;
double cur_p = p;
while(cur_p>0.5){
res ++;
cur_p*=p;
}
return res;
}
double at_least_1(int len){
return 1.-pow(1.-P, len);
}
int main() {
int T;
scanf("%d %lf %d", &N, &P, &T);
// You may perform any extra initialization here.
group_sz= min(max(get_sz((1.-P), 0.5), 1), N/2);
vector<double> expected_turns(N+1, 1e18);
for(int i = 1; i<=N; i++){
if(i==1){
expected_turns[i] = 0.;
}
else{
for(int j = 1; j<i; j++){
double total = at_least_1(j) * pow(1.-P, i-j) + at_least_1(i-j) * pow(1.-P, j) +at_least_1(j)*at_least_1(i-j);
double prop_j = (at_least_1(j) * pow(1.-P, i-j) + at_least_1(j)*at_least_1(i-j))/total;
double prop_both = (at_least_1(j)*at_least_1(i-j))/total;
double prop_i = (at_least_1(i-j) * pow(1.-P, j) + at_least_1(j)*at_least_1(i-j))/total;
double other = 1.+ prop_j*expected_turns[j] +prop_i*expected_turns[i-j];
if(other< expected_turns[i]){
split_len[i] = j;
expected_turns[i]= other;
}
}
}
}
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 'int main()':
Main.cpp:149:24: warning: unused variable 'prop_both' [-Wunused-variable]
149 | double prop_both = (at_least_1(j)*at_least_1(i-j))/total;
| ^~~~~~~~~
Main.cpp: In function 'bool test_students(std::vector<bool>)':
Main.cpp:28:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
28 | scanf(" %c", &answer);
| ~~~~~^~~~~~~~~~~~~~~~
Main.cpp: In function 'int find_first(int, int)':
Main.cpp:82:1: warning: control reaches end of non-void function [-Wreturn-type]
82 | }
| ^
Main.cpp: In function 'int main()':
Main.cpp:135:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
135 | scanf("%d %lf %d", &N, &P, &T);
| ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:172:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
172 | scanf(" %c", &verdict);
| ~~~~~^~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Execution timed out |
5715 ms |
43152 KB |
Time limit exceeded (wall clock) |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Execution timed out |
4310 ms |
24748 KB |
Time limit exceeded (wall clock) |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Execution timed out |
4377 ms |
24136 KB |
Time limit exceeded (wall clock) |
| 2 |
Halted |
0 ms |
0 KB |
- |
