結果

問題 No.75 回数の期待値の問題
ユーザー maimai
提出日時 2018-09-17 01:01:50
言語 C++17
(gcc 13.2.0 + boost 1.83.0)
結果
AC  
実行時間 2 ms / 5,000 ms
コード長 6,577 bytes
コンパイル時間 2,912 ms
コンパイル使用メモリ 212,708 KB
実行使用メモリ 4,380 KB
最終ジャッジ日時 2023-09-25 09:16:03
合計ジャッジ時間 3,583 ms
ジャッジサーバーID
(参考情報)
judge12 / judge14
このコードへのチャレンジ(β)

テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 1 ms
4,376 KB
testcase_01 AC 2 ms
4,376 KB
testcase_02 AC 2 ms
4,376 KB
testcase_03 AC 2 ms
4,376 KB
testcase_04 AC 1 ms
4,376 KB
testcase_05 AC 2 ms
4,376 KB
testcase_06 AC 1 ms
4,376 KB
testcase_07 AC 2 ms
4,376 KB
testcase_08 AC 2 ms
4,380 KB
testcase_09 AC 1 ms
4,380 KB
testcase_10 AC 2 ms
4,376 KB
testcase_11 AC 1 ms
4,380 KB
testcase_12 AC 1 ms
4,376 KB
testcase_13 AC 2 ms
4,376 KB
testcase_14 AC 2 ms
4,380 KB
testcase_15 AC 2 ms
4,380 KB
testcase_16 AC 2 ms
4,376 KB
testcase_17 AC 2 ms
4,380 KB
testcase_18 AC 2 ms
4,376 KB
testcase_19 AC 2 ms
4,376 KB
権限があれば一括ダウンロードができます

ソースコード

diff #

#pragma GCC optimize ("O3")
#include "bits/stdc++.h"

using namespace std;
using ll = long long int;

#define debugos cout
#define debug(v) {printf("L%d %s > ",__LINE__,#v);debugos<<(v)<<endl;}
#define debugv(v) {printf("L%d %s > ",__LINE__,#v);for(auto e:(v)){debugos<<e<<" ";}debugos<<endl;}
#define debuga(m,w) {printf("L%d %s > ",__LINE__,#m);for(int x=0;x<(w);x++){debugos<<(m)[x]<<" ";}debugos<<endl;}
#define debugaa(m,h,w) {printf("L%d %s >\n",__LINE__,#m);for(int y=0;y<(h);y++){for(int x=0;x<(w);x++){debugos<<(m)[y][x]<<" ";}debugos<<endl;}}
#define ALL(v) (v).begin(),(v).end()
#define repeat(cnt,l) for(remove_reference<remove_const<decltype(l)>::type>::type cnt=0;(cnt)<(l);++(cnt))
#define rrepeat(cnt,l) for(auto cnt=(l)-1;0<=(cnt);--(cnt))
#define iterate(cnt,b,e) for(auto cnt=(b);(cnt)!=(e);++(cnt))
#define diterate(cnt,b,e) for(auto cnt=(b);(cnt)!=(e);--(cnt))
const ll MD = 1000000007ll; const long double PI = 3.1415926535897932384626433832795L;
inline void assert_call(bool assertion, function<void()> f) { if (!assertion) { cerr << "assertion fault:" << endl; f(); abort(); } }
template<typename T1, typename T2> inline ostream& operator <<(ostream &o, const pair<T1, T2> p) { o << '(' << p.first << ':' << p.second << ')'; return o; }
template<typename Vec> inline ostream& _ostream_vecprint(ostream& os, const Vec& a) {
    os << '['; for (const auto& e : a) os << ' ' << e << ' '; os << ']'; return os;
}
template<typename T> inline ostream& operator<<(ostream& o, const vector<T>& v) { return _ostream_vecprint(o, v); }
template<typename T, size_t S> inline ostream& operator<<(ostream& o, const array<T, S>& v) { return _ostream_vecprint(o, v); }
template<typename T> inline T& maxset(T& to, const T& val) { return to = max(to, val); }
template<typename T> inline T& minset(T& to, const T& val) { return to = min(to, val); }
void bye(string s, int code = 0) { cout << s << endl; exit(code); }
mt19937_64 randdev(8901016);
template<typename T> inline T rand(T l, T h) { return uniform_int_distribution<T>(l, h)(randdev); }
template<> inline double rand<double>(double l, double h) { return uniform_real_distribution<double>(l, h)(randdev); }
template<> inline float rand<float>(float l, float h) { return uniform_real_distribution<float>(l, h)(randdev); }

#if defined(_WIN32) || defined(_WIN64)
#define getchar_unlocked _getchar_nolock
#define putchar_unlocked _putchar_nolock
#elif defined(__GNUC__)
#else
#define getchar_unlocked getchar
#define putchar_unlocked putchar
#endif
namespace {
#define isvisiblechar(c) (0x21<=(c)&&(c)<=0x7E)
    class MaiScanner {
    public:
        template<typename T> void input_integer(T& var) noexcept {
            var = 0; T sign = 1;
            int cc = getchar_unlocked();
            for (; cc < '0' || '9' < cc; cc = getchar_unlocked())
                if (cc == '-') sign = -1;
            for (; '0' <= cc && cc <= '9'; cc = getchar_unlocked())
                var = (var << 3) + (var << 1) + cc - '0';
            var = var * sign;
        }
        inline int c() noexcept { return getchar_unlocked(); }
        inline MaiScanner& operator>>(int& var) noexcept { input_integer<int>(var); return *this; }
        inline MaiScanner& operator>>(long long& var) noexcept { input_integer<long long>(var); return *this; }
        inline MaiScanner& operator>>(string& var) {
            int cc = getchar_unlocked();
            for (; !isvisiblechar(cc); cc = getchar_unlocked());
            for (; isvisiblechar(cc); cc = getchar_unlocked())
                var.push_back(cc);
            return *this;
        }
        template<typename IT> void in(IT begin, IT end) { for (auto it = begin; it != end; ++it) *this >> *it; }
    };
    class MaiPrinter {
    public:
        template<typename T>
        void output_integer(T var) noexcept {
            if (var == 0) { putchar_unlocked('0'); return; }
            if (var < 0)
                putchar_unlocked('-'),
                var = -var;
            char stack[32]; int stack_p = 0;
            while (var)
                stack[stack_p++] = '0' + (var % 10),
                var /= 10;
            while (stack_p)
                putchar_unlocked(stack[--stack_p]);
        }
        inline MaiPrinter& operator<<(char c) noexcept { putchar_unlocked(c); return *this; }
        inline MaiPrinter& operator<<(int var) noexcept { output_integer<int>(var); return *this; }
        inline MaiPrinter& operator<<(long long var) noexcept { output_integer<long long>(var); return *this; }
        inline MaiPrinter& operator<<(char* str_p) noexcept { while (*str_p) putchar_unlocked(*(str_p++)); return *this; }
        inline MaiPrinter& operator<<(const string& str) {
            const char* p = str.c_str();
            const char* l = p + str.size();
            while (p < l) putchar_unlocked(*p++);
            return *this;
        }
        template<typename IT> void join(IT begin, IT end, char sep = ' ') { for (bool b = 0; begin != end; ++begin, b = 1) b ? *this << sep << *begin : *this << *begin; }
    };
}
MaiScanner scanner;
MaiPrinter printer;


const double EPS = 1e-9;
double bin_search_real(double false_value, double true_value, function<bool(double)> func) {
    for (int i = 0; i < 99; ++i) {
        double mid = (true_value + false_value) / 2;
        (func(mid) ? true_value : false_value) = mid;
    }
    return true_value;
}


// bool test(double p0, int K){
//     vector<double> dp(K+10);
//     dp[0] = p0;
//     iterate(i, 1, K+1){
//         dp[i] += 1;
//         repeat(j, 6){
//             if (i-j-1 < 0) break;
//             dp[i] += dp[i-j-1]/6.0; 
//         }
//     }
//     double over = 0.0;
//     
//     iterate(j, 1, 7) {
//         iterate(k, j+1, 7)
//             over += K+j-k < 0 ? 0 : dp[K+j-k]/6;
//     }
//     //debugv(dp);
//     debug(over);
//     return p0 > over;
// }
bool test(double p0, int K){
    vector<double> dp(K+10);
    //dp[0] = p0;
    iterate(i, 1, K+1){
        dp[i] += 1;
        repeat(j, 6){
            if (i-j-1 < 0) dp[i] += p0/6.0;
            if (i-j-1 > 0) dp[i] += dp[i-j-1]/6.0; 
        }
    }
    return p0 > dp[K];
}


double solve(double p0, int K){
    vector<double> dp(K+10);
    //dp[0] = p0;
    iterate(i, 1, K+1){
        dp[i] += 1;
        repeat(j, 6){
            if (i-j-1 < 0) dp[i] += p0/6.0;
            if (i-j-1 > 0) dp[i] += dp[i-j-1]/6.0; 
        }
    }
    return dp[K];
}


int main() {
    int K;
    scanner >> K;
    
    printf("%.10f\n", bin_search_real(0.0, 1e9, [K](double p){ return test(p, K); }));
    
    return 0;
}
0