結果

問題 No.75 回数の期待値の問題
ユーザー haruki_Kharuki_K
提出日時 2020-07-09 19:36:46
言語 C++14
(gcc 10.2.0 + boost 1.73.0)
結果
AC  
実行時間 527 ms / 5,000 ms
コード長 7,893 Byte
コンパイル時間 1,773 ms
使用メモリ 8,944 KB
最終ジャッジ日時 2020-08-10 17:46:19
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
使用メモリ
testcase_00 AC 2 ms
8,900 KB
testcase_01 AC 2 ms
6,900 KB
testcase_02 AC 3 ms
8,896 KB
testcase_03 AC 3 ms
6,896 KB
testcase_04 AC 3 ms
6,892 KB
testcase_05 AC 2 ms
8,940 KB
testcase_06 AC 3 ms
8,940 KB
testcase_07 AC 2 ms
6,896 KB
testcase_08 AC 2 ms
6,892 KB
testcase_09 AC 2 ms
6,892 KB
testcase_10 AC 3 ms
6,900 KB
testcase_11 AC 3 ms
6,892 KB
testcase_12 AC 2 ms
6,896 KB
testcase_13 AC 3 ms
8,896 KB
testcase_14 AC 3 ms
8,944 KB
testcase_15 AC 4 ms
8,900 KB
testcase_16 AC 47 ms
6,896 KB
testcase_17 AC 247 ms
6,892 KB
testcase_18 AC 423 ms
6,896 KB
testcase_19 AC 527 ms
6,892 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 #

// >>> TEMPLATES
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using i32 = int32_t;
using i64 = int64_t;
using u32 = uint32_t;
using u64 = uint64_t;
#define int ll
#define double ld
#define rep(i,n) for (int i = 0; i < (int)(n); i++)
#define rep1(i,n) for (int i = 1; i <= (int)(n); i++)
#define repR(i,n) for (int i = (int)(n)-1; i >= 0; i--)
#define rep1R(i,n) for (int i = (int)(n); i >= 1; i--)
#define loop(i,a,B) for (int i = a; i B; i++)
#define loopR(i,a,B) for (int i = a; i B; i--)
#define all(x) (x).begin(), (x).end()
#define allR(x) (x).rbegin(), (x).rend()
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define fst first
#define snd second
template <class Int> auto constexpr inf = numeric_limits<Int>::max()/2-1;
auto constexpr INF32 = inf<int32_t>;
auto constexpr INF64 = inf<int64_t>;
auto constexpr INF   = inf<int>;
#ifdef LOCAL
#include "debug.hpp"
#else
#define dump(...) (void)(0)
#define say(x) (void)(0)
#define debug if (0)
#endif
template <class T> using pque_max = priority_queue<T>;
template <class T> using pque_min = priority_queue<T, vector<T>, greater<T> >;
template <class T, class = typename T::iterator, class = typename enable_if<!is_same<T, string>::value>::type>
ostream& operator<<(ostream& os, T const& v) { bool f = true; for (auto const& x : v) os << (f ? "" : " ") << x, f = false; return os; }
template <class T, class = typename T::iterator, class = typename enable_if<!is_same<T, string>::value>::type>
istream& operator>>(istream& is, T &v) { for (auto& x : v) is >> x; return is; }
template <class T, class S> ostream& operator<<(ostream& os, pair<T,S> const& p) { return os << "(" << p.first << ", " << p.second << ")"; }
template <class T, class S> istream& operator>>(istream& is, pair<T,S>& p) { return is >> p.first >> p.second; }
struct IOSetup { IOSetup() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(15); } } iosetup;
template <class F> struct FixPoint : private F {
    constexpr FixPoint(F&& f) : F(forward<F>(f)) {}
    template <class... T> constexpr auto operator()(T&&... x) const { return F::operator()(*this, forward<T>(x)...); }
};
struct MakeFixPoint {
    template <class F> constexpr auto operator|(F&& f) const { return FixPoint<F>(forward<F>(f)); }
};
#define MFP MakeFixPoint()|
#define def(name, ...) auto name = MFP [&](auto &&name, __VA_ARGS__)
template <class T, size_t d> struct vec_impl {
    using type = vector<typename vec_impl<T,d-1>::type>;
    template <class... U> static type make_v(size_t n, U&&... x) { return type(n, vec_impl<T,d-1>::make_v(forward<U>(x)...)); }
};
template <class T> struct vec_impl<T,0> { using type = T; static type make_v(T const& x = {}) { return x; } };
template <class T, size_t d = 1> using vec = typename vec_impl<T,d>::type;
template <class T, size_t d = 1, class... Args> auto make_v(Args&&... args) { return vec_impl<T,d>::make_v(forward<Args>(args)...); }
template <class T> void quit(T const& x) { cout << x << endl; exit(0); }
template <class T, class U> constexpr bool chmin(T& x, U const& y) { if (x > y) { x = y; return true; } return false; }
template <class T, class U> constexpr bool chmax(T& x, U const& y) { if (x < y) { x = y; return true; } return false; }
template <class It> constexpr auto sumof(It b, It e) { return accumulate(b,e,typename iterator_traits<It>::value_type{}); }
template <class T> int sz(T const& x) { return x.size(); }
template <class C, class T> int lbd(C const& v, T const& x) {
    return lower_bound(v.begin(), v.end(), x)-v.begin();
}
template <class C, class T> int ubd(C const& v, T const& x) {
    return upper_bound(v.begin(), v.end(), x)-v.begin();
}
template <class C, class F> int ppt(C const& v, F f) {
    return partition_point(v.begin(), v.end(), f)-v.begin();
}
template <class Int> struct Random {
    mt19937_64 mt{random_device{}()};
    //mt19937_64 mt{(unsigned)time(0)};
    Int a,b; // [a,b]
    Random(Int a, Int b) : a(a), b(b) {}
    Int operator()() { return uniform_int_distribution<Int>(a,b)(mt); }
};
template <class Int> Int rand(Int a, Int b) { // [a,b]
    static mt19937_64 mt{random_device{}()};
    return uniform_int_distribution<Int>(a,b)(mt);
}
// <<<
// >>> matrix
template <class T>
struct Matrix {
    int n,m;
    vector<vector<T> > a;
    Matrix() {}
    Matrix(int n, int m) : n(n), m(m), a(n) {
        assert(n > 0 && m > 0);
        rep (i,n) a[i].resize(m);
    }
    Matrix(initializer_list<initializer_list<T> > init) {
        for (auto ls : init) {
            a.emplace_back();
            for (auto x : ls) a.back().emplace_back(x);
        }
        n = a.size(); assert(n > 0);
        m = a[0].size(); assert(m > 0);
    }
    vector<T> const& operator[](int i) const {
        assert(0 <= i && i < n);
        return a[i];
    }
    vector<T> & operator[](int i) {
        assert(0 <= i && i < n);
        return a[i];
    }
    bool operator==(Matrix const& x) const {
        if (n != x.n || m != x.m) return false;
        rep (i,n) rep (j,m) if (a[i][j] != x[i][j]) return false;
        return true;
    }
    bool operator!=(Matrix const& x) const {
        return !(*this == x);
    }
    Matrix& operator+=(Matrix const& x) {
        assert(n == x.n && m == x.m);
        rep (i,n) rep (j,m) a[i][j] += x[i][j];
        return *this;
    }
    Matrix& operator-=(Matrix const& x) {
        assert(n == x.n && m == x.m);
        rep (i,n) rep (j,m) a[i][j] -= x[i][j];
        return *this;
    }
    Matrix operator+(Matrix const& x) const { return Matrix(*this) += x; }
    Matrix operator-(Matrix const& x) const { return Matrix(*this) -= x; }
    Matrix operator*(Matrix const& x) const {
        assert(m == x.n);
        Matrix ret(n,x.m);
        rep (i,n) rep (j,m) rep (k,x.m) ret[i][k] += a[i][j] * x[j][k];
        return ret;
    }
    Matrix& operator*=(Matrix const& x) {
        auto res = (*this)*x;
        swap(a, res.a);
        return *this;
    }
	Matrix operator+() const { return *this; }
	Matrix operator-() const {
		Matrix x = *this;
        rep (i,n) rep (j,m) x[i][j] = -x[i][j];
		return x;
	}
    Matrix& operator*=(T const& c) {
        rep (i,n) rep (j,m) a[i][j] *= c;
        return *this;
    }
    Matrix operator*(T const& c) const { return Matrix(*this) *= c; }
    friend Matrix operator*(T const& c, Matrix const& x) {
        Matrix ret = x;
        rep (i,x.n) rep (j,x.m) ret[i][j] = c*x[i][j];
        return ret;
    }
    Matrix& operator/=(T const& c) {
        rep (i,n) rep (j,m) a[i][j] /= c;
        return *this;
    }
    Matrix operator/(T const& c) const {
        return Matrix(*this) /= c;
    }
    static Matrix identity(int n) {
        Matrix ret(n,n);
        rep (i,n) ret[i][i] = 1;
        return ret;
    }
    Matrix pow(ll k) const {
        assert(n == m); assert(k >= 0);
        Matrix v = *this, r = Matrix::identity(n);
        for (; k > 0; k >>= 1, v *= v) if (k&1) r *= v;
        return r;
    }
    friend istream& operator>>(istream& is, Matrix& x) {
        rep (i,x.n) rep (j,x.m) is >> x[i][j];
        return is;
    }
#ifdef LOCAL
    friend string to_s(Matrix const& x) {
        string ret;
        rep (i,x.n) {
            ret += "\n(";
            rep (j,x.m) ret += " " + to_s(x[i][j]);
            ret += " )";
        }
        return ret += "\n";
    }
#endif
};
// <<<

int32_t main() {
    int k; cin >> k;

    Matrix<double> A(k,k),v(k,1);
    rep (i,k) rep1 (x,6) {
        int j = i+x;
        if (j == k) continue;
        if (j > k) j = 0;
        A[i][j] += 1.0/6.0;
    }

    const double eps = 1e-6;
    int cnt = 0;
    while (true) {
        auto u = A*v;
        rep (i,k) u[i][0] += 1;
        double d = 0;
        rep (i,k) chmax(d, abs(u[i][0]-v[i][0]));
        if (d < eps) break;
        v = u;
        ++cnt;
    }

    cout << v[0] << endl;
    dump(cnt);
}
0