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답안 #1074644

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
1074644 2024-08-25T11:38:11 Z GrindMachine COVID tests (CEOI24_covid) C++17
10 / 100
 7000 ms 1104 KB 
#include <bits/stdc++.h>
using namespace std;
 
typedef long long int ll;
typedef long double ld;
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

/*

refs:
edi

*/ 

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;
    std::vector<ld> dp(n+5,1e9);
    std::vector<ld> dp2(n+5,1e9);
    std::vector<int> par(n+5,-1);
    std::vector<int> par2(n+5,-1);
    dp[0] = dp[1] = 0;
    dp2[0] = 0, dp2[1] = 1;
    par2[1] = 1;
    for(int i = 2; i <= n; ++i){
        ld tot_neg = powl((ld)1-P, i);
        for(int j = 1; j < i; j++){
            ld all_neg2 = powl((ld)1-P,i-j);
            ld all_neg = powl((ld)1-P,j) * (1 - all_neg2) / (1 - tot_neg);
            ld val = 1+all_neg*dp[i-j];
            val += (1-all_neg)*(dp[j]+dp2[i-j]);
            if(val < dp[i]){
                dp[i] = val;
                par[i] = j;                
            }
        }
        for(int j = 1; j <= i; j++){
            ld all_neg = powl((ld)1-P,j);
            ld val = 1+(1-all_neg)*dp[j]+dp2[i-j];
            if(val < dp2[i]){
                dp2[i] = val;
                par2[i] = j;                
            }
        }
        // std::cout << "at N = " << i << " got ev " << dp[i] << " and par is " << par[i] << '\n';
        // std::cout << "at N = " << i << " got ev " << dp2[i] << " and par is " << par2[i] << '\n';
    }

    vector<bool> ans(n);

    auto go = [&](int l, int r, int t, auto &&go) -> void{
        // t = 0: positive not guaranteed (use dp2)
        // t = 1: at least 1 positive (use dp)
        if(l > r) return;

        int len = r-l+1;

        if(t){
            if(len == 1){
                ans[l] = 1;
                return;
            }

            int j = par[len];
            vector<bool> mask(n);
            for(int k = l; k < l+j; ++k){
                mask[k] = 1;
            }

            if(!test_students(mask)){
                // no positive on left
                // at least 1 positive on right
                go(l+j,r,1,go);
            }
            else{
                // at least 1 positive on left
                // not guaranteed on right
                go(l,l+j-1,1,go);
                go(l+j,r,0,go);
            }
        }
        else{
            if(len == 1){
                vector<bool> mask(n);
                mask[l] = 1;
                ans[l] = test_students(mask);
                return;
            }

            int j = par2[len];
            vector<bool> mask(n);
            for(int k = l; k < l+j; ++k){
                mask[k] = 1;
            }

            if(!test_students(mask)){
                // no positive on left
                // not guaranteed on right
                go(l+j,r,0,go);
            }
            else{
                // positive on left
                // not guaranteed on right
                go(l,l+j-1,1,go);
                go(l+j,r,0,go);
            }
        }
    };

    go(0,n-1,0,go);
    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:107:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  107 |     scanf(" %c", &answer);
      |     ~~~~~^~~~~~~~~~~~~~~~
Main.cpp: In function 'int main()':
Main.cpp:224:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  224 |     scanf("%d %lf %d", &N, &P, &T);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:240:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  240 |         scanf(" %c", &verdict);
      |         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #0
0.0 / 0.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 344 KB Output is correct

Subtask #1
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 737 ms 696 KB Output is correct
2 Correct 750 ms 696 KB Output is correct
3 Correct 725 ms 700 KB Output is correct
4 Correct 783 ms 696 KB Output is correct
5 Correct 736 ms 592 KB Output is correct
6 Correct 751 ms 592 KB Output is correct
7 Correct 733 ms 704 KB Output is correct
8 Correct 746 ms 712 KB Output is correct
9 Correct 739 ms 700 KB Output is correct
10 Correct 732 ms 444 KB Output is correct
11 Correct 746 ms 440 KB Output is correct
12 Correct 749 ms 696 KB Output is correct
13 Correct 711 ms 1104 KB Output is correct
14 Correct 747 ms 592 KB Output is correct
15 Correct 751 ms 592 KB Output is correct
16 Correct 62 ms 592 KB Output is correct
17 Correct 718 ms 344 KB Output is correct

Subtask #2
0.0 / 90.0

# 결과 실행 시간 메모리 Grader output
1 Execution timed out 7039 ms 452 KB Time limit exceeded
2 Halted 0 ms 0 KB -