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Submission #1074154

# Submission time Handle Problem Language Result Execution time Memory
1074154 2024-08-25T08:26:43 Z GrindMachine COVID tests (CEOI24_covid) C++17
43.54 / 100
 2424 ms 344 KB 
#include <bits/stdc++.h>
using namespace std;
 
typedef long long int ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
 
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define conts continue
#define sz(a) (int)a.size()
#define ff first
#define ss second
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define ceil2(x,y) ((x+y-1)/(y))
 
#define rep(i,n) for(int i = 0; i < n; ++i)
#define rep1(i,n) for(int i = 1; i <= n; ++i)
#define rev(i,s,e) for(int i = s; i >= e; --i)
#define trav(i,a) for(auto &i : a)
 
template<typename T>
void amin(T &x, T y){
    x = min(x,y);
}
 
template<typename T>
void amax(T &x, T y){
    x = max(x,y);
}
 
template<typename A,typename B>
string to_string(pair<A,B> p);
 
string to_string(const string &s){
    return "'"+s+"'";
}
 
string to_string(const char* s){
    return to_string((string)s);
}
 
string to_string(bool b){
    return b?"true":"false";
}
 
template<typename A>
string to_string(A v){
    string res = "{";
    trav(x,v){
        res += to_string(x)+",";
    }
    if(res.back() == ',') res.pop_back();
    res += "}";
    return res;
}
 
template<typename A,typename B>
string to_string(pair<A,B> p){
    return "("+to_string(p.ff)+","+to_string(p.ss)+")";
}
 
#define debug(x) cout << "[" << #x << "]: "; cout << to_string(x) << endl
 
const int MOD = 1e9 + 7;
const int NN = 1e5 + 5;
const int inf1 = 1e9 + 5;
const ll inf2 = (ll)1e18 + 5;
 
bool dbg = false;

/// 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) {
    if(dbg) return 'P';

    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);
    // return answer;
 
    int n = N;
    vector<bool> ans(n);
 
    vector<int> pos(n);
    iota(all(pos),0);
 
    mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
    shuffle(all(pos),rng);
 
    auto go = [&](int l, int r, auto &&go){
        if(l > r) return;
 
        vector<bool> mask(n);
        for(int i = l; i <= r; ++i){
            mask[pos[i]] = 1;
        }
 
        if(!test_students(mask)) return;
 
        if(l == r){
            ans[pos[l]] = 1;
            return;
        }
 
        int len = r-l+1;
        int block_cnt = min(len,3);
 
        // double expected = len*P;
        // int block_cnt = max((int)(len/(expected+1)),2);
        // amin(block_cnt,len);
        // amin(block_cnt,3);
 
        int s1 = len/block_cnt, s2 = ceil2(len,block_cnt);
        int c1 = block_cnt, c2 = len%block_cnt;
        c1 -= c2;
 
        int pos = l;
        vector<pii> nxt;
 
        rep1(iter,block_cnt){
            if(iter <= c1){
                nxt.pb({pos,pos+s1-1});
                pos += s1;
            }
            else{
                nxt.pb({pos,pos+s2-1});
                pos += s2;
            }
        }
            
        assert(pos == r+1);
 
        for(auto [lx,rx] : nxt){
            go(lx,rx,go);
        }        
    };
    
    double eps = 1e-6;
    int B = 0;

    if(abs(P-0.001) <= eps){
        B = n;
    }
    else if(abs(P-0.005256) <= eps){
        B = 50;
    }
    else if(abs(P-0.011546) <= eps){
        B = 50;
    }
    else{
        B = 25;
    }

    for(int i = 0; i < n; i += B){
        go(i,min(i+B-1,n-1),go);
    }

    // go(0,n-1,go);
 
    // rep(i,n){
    //     vector<bool> mask(n);
    //     mask[i] = 1;
    //     if(test_students(mask)){
    //         ans[i] = 1;
    //     }
    // }
 
    return ans;
}
 
int main() {
    #ifdef LOCAL
        dbg = true;
    #endif

    int T;
    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:99:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   99 |     scanf(" %c", &answer);
      |     ~~~~~^~~~~~~~~~~~~~~~
Main.cpp: In function 'int main()':
Main.cpp:209:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  209 |     scanf("%d %lf %d", &N, &P, &T);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:225:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  225 |         scanf(" %c", &verdict);
      |         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #0
0.0 / 0.0

# Verdict Execution time Memory Grader output
1 Correct 1 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 13 ms 344 KB Output is correct
4 Correct 14 ms 344 KB Output is correct
5 Correct 17 ms 344 KB Output is correct
6 Correct 14 ms 344 KB Output is correct
7 Correct 9 ms 344 KB Output is correct
8 Correct 14 ms 344 KB Output is correct
9 Correct 8 ms 344 KB Output is correct
10 Correct 7 ms 344 KB Output is correct
11 Correct 9 ms 344 KB Output is correct
12 Correct 8 ms 344 KB Output is correct
13 Correct 9 ms 344 KB Output is correct
14 Correct 11 ms 344 KB Output is correct
15 Correct 10 ms 344 KB Output is correct
16 Correct 14 ms 344 KB Output is correct
17 Correct 1 ms 344 KB Output is correct

Subtask #2
33.540000003 / 90.0

# Verdict Execution time Memory Grader output
1 Correct 44 ms 344 KB Output is correct (P=0.001, F=15.1, Q=16.8) -> 62.05 points
2 Correct 230 ms 344 KB Output is correct (P=0.005256, F=51.1, Q=72.6) -> 33.54 points
3 Correct 311 ms 344 KB Output is correct (P=0.011546, F=94.9, Q=131.3) -> 35.51 points
4 Correct 529 ms 344 KB Output is correct (P=0.028545, F=191.5, Q=257.5) -> 37.84 points
5 Correct 763 ms 344 KB Output is correct (P=0.039856, F=246.3, Q=330.0) -> 38.15 points
6 Correct 1251 ms 344 KB Output is correct (P=0.068648, F=366.2, Q=485.5) -> 39.08 points
7 Correct 1417 ms 344 KB Output is correct (P=0.104571, F=490.3, Q=639.3) -> 40.62 points
8 Correct 1730 ms 344 KB Output is correct (P=0.158765, F=639.1, Q=816.0) -> 42.71 points
9 Correct 2424 ms 344 KB Output is correct (P=0.2, F=731.4, Q=933.4) -> 42.76 points