結果

問題 No.1595 The Final Digit
コンテスト
ユーザー qLethon
提出日時 2021-07-09 22:07:10
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 3 ms / 2,000 ms
コード長 6,659 bytes
コンパイル時間 2,324 ms
コンパイル使用メモリ 203,412 KB
最終ジャッジ日時 2025-01-22 21:52:12
ジャッジサーバーID
（参考情報） 		judge2 / judge3
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ファイルパターン 結果
sample AC * 3
other AC * 17
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 # 

#include <bits/stdc++.h>

using namespace std;

template< class T >
struct Matrix {
  vector< vector< T > > A;

  Matrix() {}

  Matrix(size_t n, size_t m) : A(n, vector< T >(m, 0)) {}

  Matrix(size_t n) : A(n, vector< T >(n, 0)) {};

  size_t height() const {
    return (A.size());
  }

  size_t width() const {
    return (A[0].size());
  }

  inline const vector< T > &operator[](int k) const {
    return (A.at(k));
  }

  inline vector< T > &operator[](int k) {
    return (A.at(k));
  }

  static Matrix I(size_t n) {
    Matrix mat(n);
    for(int i = 0; i < n; i++) mat[i][i] = 1;
    return (mat);
  }

  Matrix &operator+=(const Matrix &B) {
    size_t n = height(), m = width();
    assert(n == B.height() && m == B.width());
    for(int i = 0; i < n; i++)
      for(int j = 0; j < m; j++)
        (*this)[i][j] += B[i][j];
    return (*this);
  }

  Matrix &operator-=(const Matrix &B) {
    size_t n = height(), m = width();
    assert(n == B.height() && m == B.width());
    for(int i = 0; i < n; i++)
      for(int j = 0; j < m; j++)
        (*this)[i][j] -= B[i][j];
    return (*this);
  }

  Matrix &operator*=(const Matrix &B) {
    size_t n = height(), m = B.width(), p = width();
    assert(p == B.height());
    vector< vector< T > > C(n, vector< T >(m, 0));
    for(int i = 0; i < n; i++)
      for(int j = 0; j < m; j++)
        for(int k = 0; k < p; k++)
          C[i][j] = (C[i][j] + (*this)[i][k] * B[k][j]);
    A.swap(C);
    return (*this);
  }

  Matrix &operator^=(long long k) {
    Matrix B = Matrix::I(height());
    while(k > 0) {
      if(k & 1) B *= *this;
      *this *= *this;
      k >>= 1LL;
    }
    A.swap(B.A);
    return (*this);
  }

  Matrix operator+(const Matrix &B) const {
    return (Matrix(*this) += B);
  }

  Matrix operator-(const Matrix &B) const {
    return (Matrix(*this) -= B);
  }

  Matrix operator*(const Matrix &B) const {
    return (Matrix(*this) *= B);
  }

  Matrix operator^(const long long k) const {
    return (Matrix(*this) ^= k);
  }

  friend ostream &operator<<(ostream &os, Matrix &p) {
    size_t n = p.height(), m = p.width();
    for(int i = 0; i < n; i++) {
      os << "[";
      for(int j = 0; j < m; j++) {
        os << p[i][j] << (j + 1 == m ? "]\n" : ",");
      }
    }
    return (os);
  }


  T determinant() {
    Matrix B(*this);
    assert(width() == height());
    T ret = 1;
    for(int i = 0; i < width(); i++) {
      int idx = -1;
      for(int j = i; j < width(); j++) {
        if(B[j][i] != 0) idx = j;
      }
      if(idx == -1) return (0);
      if(i != idx) {
        ret *= -1;
        swap(B[i], B[idx]);
      }
      ret *= B[i][i];
      T vv = B[i][i];
      for(int j = 0; j < width(); j++) {
        B[i][j] /= vv;
      }
      for(int j = i + 1; j < width(); j++) {
        T a = B[j][i];
        for(int k = 0; k < width(); k++) {
          B[j][k] -= B[i][k] * a;
        }
      }
    }
    return (ret);
  }
};

template <std::uint_fast64_t Modulus> class modint {
    using u64 = std::uint_fast64_t;
    u64 a;

    public:

    template <class INT>
    constexpr modint(const INT x = 0) noexcept : a(x >= 0 ? x % Modulus : x % int_fast64_t(Modulus) + Modulus) {}
    constexpr modint(const u64 x = 0) noexcept : a(x % Modulus) {}
    constexpr u64 &value() noexcept { return a; }
    constexpr const u64 &value() const noexcept { return a; }
    constexpr modint operator+(const modint rhs) const noexcept {
        return modint(*this) += rhs;
    }
    constexpr modint operator-(const modint rhs) const noexcept {
        return modint(*this) -= rhs;
    }
    constexpr modint operator*(const modint rhs) const noexcept {
        return modint(*this) *= rhs;
    }
    constexpr modint operator/(const modint rhs) const noexcept {
        return modint(*this) /= rhs;
    }
    constexpr modint &operator+=(const modint rhs) noexcept {
        a += rhs.a;
        if (a >= Modulus) {
            a -= Modulus;
        }
        return *this;
    }
    constexpr modint &operator-=(const modint rhs) noexcept {
        if (a < rhs.a) {
            a += Modulus;
        }
        a -= rhs.a;
        return *this;
    }
    constexpr modint &operator*=(const modint rhs) noexcept {
        a = a * rhs.a % Modulus;
        return *this;
    }
    constexpr modint &operator/=(modint rhs) noexcept {
        u64 exp = Modulus - 2;
        while (exp) {
            if (exp % 2) {
                *this *= rhs;
            }
        rhs *= rhs;
        exp /= 2;
        }
        return *this;
    }

    constexpr bool operator<(const modint& rhs) const noexcept {return this->a < rhs.a;}
    constexpr bool operator>(const modint& rhs) const noexcept {return rhs < *this;}
    constexpr bool operator<=(const modint& rhs) const noexcept {return !(*this > rhs);}
    constexpr bool operator>=(const modint& rhs) const noexcept {return !(*this < rhs);}
    constexpr bool operator==(const modint& rhs) const noexcept {return this->a == rhs.a;}
    constexpr bool operator!=(const modint& rhs) const noexcept {return !(*this == rhs);}

    constexpr modint& operator++() noexcept {
        *this += modint(1);
        return *this;
    }
    constexpr modint operator++(int) noexcept {
        modint tmp(*this);
        ++(*this);
        return tmp;
    }
    constexpr modint& operator--() noexcept {
        *this -= modint(1);
        return *this;
    }
    constexpr modint operator--(int) noexcept {
        modint tmp(*this);
        --(*this);
        return tmp;
    }
    constexpr modint operator-() const noexcept {
        return modint(0) - *this;
    }

    template <std::uint_fast64_t M>
    friend constexpr std::ostream& operator<<(std::ostream& os, const modint<M>& rhs) noexcept {
        os << rhs.a;
        return os;
    }
    template <std::uint_fast64_t M>
    friend constexpr std::istream& operator>>(std::istream& is, modint<M>& rhs) noexcept {
        int64_t tmp;
        is >> tmp;
        rhs = modint(tmp);
        return is;
    }

    constexpr modint pow(const u64 k) const noexcept {
        if (k == 0)
            return 1;
        if (k % 2 == 0){
            modint res = pow(k / 2);
            return res * res;
        }
        return pow(k - 1) * modint(*this);
    }

    template <typename T>
    operator const T (){return a;}

};

using mint = modint<10>;

int main(){
    int64_t p, q, r, k;
    cin >> p >> q >> r >> k;

    Matrix<mint> A(3);
    for (int i = 0; i < 3; i++)
        A[0][i] = 1;
    A[1][0] = 1;
    A[2][1] = 1;

    A ^= (k - 3);
    Matrix<mint> x(3, 1);
    x[0][0] = r; x[1][0] = q; x[2][0] = p;

    int ans = (A * x)[0][0];
    cout << ans << endl;
}
0