modint
勝手にmodしてくれるやつ。嬉しい。
じょえから拝借
code:modint01.cpp
template <typename T>
T pow(T a, long long n, T e = 1) {
T ret = e;
while (n) {
if (n & 1) ret *= a;
a *= a;
n >>= 1;
}
return ret;
}
template <int mod>
struct ModInt {
int x;
ModInt() : x(0) {}
ModInt(long long x_) {
if ((x = x_ % mod + mod) >= mod) x -= mod;
}
ModInt& operator+=(ModInt rhs) {
if ((x += rhs.x) >= mod) x -= mod;
return *this;
}
ModInt& operator-=(ModInt rhs) {
if ((x -= rhs.x) < 0) x += mod;
return *this;
}
ModInt& operator*=(ModInt rhs) {
x = (unsigned long long)x * rhs.x % mod;
return *this;
}
ModInt& operator/=(ModInt rhs) {
x = (unsigned long long)x * rhs.inv().x % mod;
return *this;
}
ModInt operator-() const { return -x < 0 ? mod - x : -x; }
ModInt operator+(ModInt rhs) const { return ModInt(*this) += rhs; }
ModInt operator-(ModInt rhs) const { return ModInt(*this) -= rhs; }
ModInt operator*(ModInt rhs) const { return ModInt(*this) *= rhs; }
ModInt operator/(ModInt rhs) const { return ModInt(*this) /= rhs; }
bool operator==(ModInt rhs) const { return x == rhs.x; }
bool operator!=(ModInt rhs) const { return x != rhs.x; }
ModInt inv() const { return pow(*this, mod - 2); }
friend ostream& operator<<(ostream& s, ModInt<mod> a) {
s << a.x;
return s;
}
friend istream& operator>>(istream& s, ModInt<mod>& a) {
s >> a.x;
return s;
}
};
using mint = ModInt<1000000007>;