1. Power modulo
int pow_mod(int x, int n, int m = INF)
Returns $x^n$ mod $m$
Constraints
- $0\leq n$
- $1\leq m$
Complexity
- $O(\log n)$
constexpr long long safe_mod(long long x, long long m) {
x %= m;
if (x < 0) x += m;
return x;
}
struct barrett {
unsigned long long _m;
unsigned long long im;
explicit barrett(unsigned long long m) : _m(m), im((unsigned long long)(-1) / m + 1) {}
unsigned long long umod() const { return _m; }
unsigned long long mul(unsigned int a, unsigned int b) const {
unsigned long long z = a;
z *= b;
unsigned long long x = (unsigned long long)(((unsigned __int128)(z)*im) >> 64);
unsigned long long y = x * _m;
return (unsigned long long)(z - y + (z < y ? _m : 0));
}
};
long long pow_mod(long long x, long long n, long long m = INTINF) {
assert(0 <= n && 1 <= m);
if (m == 1) return 0;
barrett bt((unsigned long long)(m));
unsigned long long r = 1, y = (unsigned long long)(safe_mod(x, m));
while (n) {
if (n & 1) r = bt.mul(r, y);
y = bt.mul(y, y);
n >>= 1;
}
return r;
}
2. Modular multiplicative inverse
int inv_mod(int x, int y)
Returns an integer $y$ such that $0\leq y<m$ and $xy\equiv 1(\text{mod }m)$
Constraints
- $\text{gcd}(x,m)=1$
- $1\leq m$
Complexity
- $O(\log m)$
constexpr long long safe_mod(long long x, long long m) {
x %= m;
if (x < 0) x += m;
return x;
}
constexpr std::pair<long long, long long> inv_gcd(long long a, long long b) {
a = safe_mod(a, b);
if (a == 0) return {b, 0};
long long s = b, t = a;
long long m0 = 0, m1 = 1;
while (t) {
long long u = s / t;
s -= t * u;
m0 -= m1 * u;
auto tmp = s;
s = t;
t = tmp;
tmp = m0;
m0 = m1;
m1 = tmp;
}
if (m0 < 0) m0 += b / s;
return {s, m0};
}
long long inv_mod(long long x, long long m) {
assert(1 <= m);
auto z = inv_gcd(x, m);
assert(z.first == 1);
return z.second;
}
3. Sieve of prime
vector<bool> prime_sieve(int n)
Returns a vector ranging from $0$ to $n$, indicating whether each integer is a prime.
Complexity
- $O(n)$
vector<bool> prime_sieve(long long N) {
vector<long long> p_(N+1, 0);
vector<bool> is_prime_(N+1, 1);
for (int i = 2, t = 0; i < N; ++i) {
if (is_prime_[i]) p_[t++] = i;
for (int j = 0; j < t && i*p_[j] < MAXN; ++j) {
is_prime_[i*p_[j]] = 0;
if (!(i % p_[j])) break;
}
}
return is_prime_;
}
4. Is prime
bool is_prime(int n)
Return a boolean indicate where $n$ is prime.
Complexity
- $O(\sqrt{n})$
bool is_prime(long long n) {
if (n <= 2) return 1;
for (int i = 2; i <= sqrt(n); ++i) {
if (!(n % i)) return 0;
}
return 1;
}
5. Integer factorization
vector<pair<int, int>> factorization(long long n)
Return a vector of pairs, $\{p_i,c_i\}$ represents $p_i^{c_i}$ is a factor of $n$
Complexity
- $O(\sqrt{n})$
std::vector<pair<int, int>> factors(int m) {
std::vector<pair<int, int>> result;
for (int i = 2; (long long)(i)*i <= m; i++) {
if (m % i == 0) {
int cnt = 0;
while (m % i == 0) {
m /= i;
++cnt;
}
result.push_back(make_pair(i, cnt));
}
}
if (m > 1) result.push_back(make_pair(m, 1));
return result;
}
6. Mod int
using mint = atcoder::static_modint<998244353>;
using mint = atcoder::modint;
mint::set_mod(998244353);
namespace atcoder{namespace internal{template<class T>using is_integral=typename std::is_integral<T>;template<class T>using is_signed_int=typename std::conditional<is_integral<T>::value&&std::is_signed<T>::value,std::true_type,std::false_type>::type;template<class T>using is_unsigned_int=typename std::conditional<is_integral<T>::value&&std::is_unsigned<T>::value,std::true_type,std::false_type>::type;template<class T>using to_unsigned=typename std::conditional<is_signed_int<T>::value,std::make_unsigned<T>,std::common_type<T>>::type;template<class T>using is_signed_int_t=std::enable_if_t<is_signed_int<T>::value>;template<class T>using is_unsigned_int_t=std::enable_if_t<is_unsigned_int<T>::value>;template <class T>using to_unsigned_t=typename to_unsigned<T>::type;constexpr int safe_mod(int x,int m){x%=m;if(x<0)x+=m;return x;}struct barrett{unsigned int _m;unsigned int im;explicit barrett(unsigned int m):_m(m),im((unsigned int)(-1)/m+1){}unsigned int umod()const{return _m;}unsigned int mul(unsigned int a,unsigned int b)const{unsigned int z=a;z*=b;unsigned int x=(unsigned int)(((unsigned __int128)(z)*im)>>64);unsigned int y=x*_m;return(unsigned int)(z-y+(z<y?_m:0));}};constexpr std::pair<int,int> inv_gcd(int a,int b){a=safe_mod(a,b);if(a==0){return{b,0};}int s=b,t=a;int m0=0,m1=1;while(t){int u=s/t;s-=t*u;m0-=m1*u;auto tmp=s;s=t;t=tmp;tmp=m0;m0=m1;m1=tmp;}if(m0<0)m0+=b/s;return{s,m0};}constexpr int pow_mod_constexpr(int x,int n,int m){if(m==1)return 0;unsigned int _m=(unsigned int)(m);unsigned int r=1;unsigned int y=safe_mod(x,m);while(n){if(n&1)r=(r*y)% _m;y=(y*y)% _m;n>>=1;}return r;}constexpr bool is_prime_constexpr(int n){if(n<=1)return false;if(n==2||n==7||n==61)return true;if(n%2==0){return false;}int d=n-1;while(d%2==0)d/=2;constexpr int bases[3]={2,7,61};for(int a:bases){int t=d;int y=pow_mod_constexpr(a,t,n);while(t!=n-1&&y!=1&&y!=n-1){y=y*y%n;t<<=1;}if(y!=n-1&&t%2==0){return false;}}return true;}template <int n>constexpr bool is_prime=is_prime_constexpr(n);struct modint_base{};struct static_modint_base:modint_base{};template <class T>using is_modint=std::is_base_of<modint_base,T>;template <class T>using is_modint_t=std::enable_if_t<is_modint<T>::value>;}template <int m,std::enable_if_t<(1<=m)>* =nullptr>struct static_modint:internal::static_modint_base{using mint=static_modint;public:static constexpr int mod(){return m;}static mint raw(int v){mint x;x._v=v;return x;}static_modint():_v(0){}template<class T,internal::is_signed_int_t<T>* =nullptr>static_modint(T v){int x=(int)(v %(int)(umod()));if(x<0)x+=umod();_v=(unsigned int)(x);}template <class T,internal::is_unsigned_int_t<T>* =nullptr>static_modint(T v){_v=(unsigned int)(v%umod());}unsigned int val()const{return _v;}mint&operator++(){_v++;if(_v==umod())_v=0;return *this;}mint&operator--(){if(_v==0)_v=umod();_v--;return *this;}mint operator++(int32_t){mint result=*this;++*this;return result;}mint operator--(int32_t){mint result=*this;--*this;return result;}mint&operator+=(const mint&rhs){_v+=rhs._v;if(_v>=umod())_v-=umod();return *this;}mint&operator-=(const mint&rhs){_v-=rhs._v;if(_v>=umod())_v+=umod();return *this;}mint&operator*=(const mint&rhs){unsigned int z=_v;z*=rhs._v;_v=(unsigned int)(z%umod());return *this;}mint&operator/=(const mint&rhs){return *this=*this*rhs.inv();}
mint operator+()const{return *this;}mint operator-()const{return mint()-*this;}mint pow(int n)const{assert(0<=n);mint x=*this,r=1;while(n){if(n&1)r*=x;x*=x;n>>=1;}return r;}mint inv()const{if(prime){assert(_v);return pow(umod()-2);}else{auto eg=internal::inv_gcd(_v,m);assert(eg.first==1);return eg.second;}}friend mint operator+(const mint&lhs,const mint&rhs){return mint(lhs)+=rhs;}friend mint operator-(const mint&lhs,const mint&rhs){return mint(lhs)-=rhs;}friend mint operator*(const mint&lhs,const mint&rhs){return mint(lhs)*=rhs;}friend mint operator/(const mint&lhs,const mint&rhs){return mint(lhs)/=rhs;}friend bool operator==(const mint&lhs,const mint&rhs){return lhs._v==rhs._v;}friend bool operator!=(const mint&lhs,const mint&rhs){return lhs._v!=rhs._v;}private:unsigned int _v;static constexpr unsigned int umod(){return m;}static constexpr bool prime=internal::is_prime<m>;};template<int id>struct dynamic_modint:internal::modint_base{using mint=dynamic_modint;public:static int mod(){ return(int)(bt.umod()); }static void set_mod(int m){assert(1<=m);bt=internal::barrett(m);}static mint raw(int v){mint x;x._v=v;return x;}dynamic_modint():_v(0){}template<class T,internal::is_signed_int_t<T>* =nullptr>dynamic_modint(T v){int x=(int)(v %(int)(mod()));if(x<0)x+=mod();_v=(unsigned int)(x);}template<class T,internal::is_unsigned_int_t<T>* =nullptr>dynamic_modint(T v){_v=(unsigned int)(v%mod());}unsigned int val()const{return _v;}mint&operator++(){_v++;if(_v==umod())_v=0;return *this;}mint&operator--(){if(_v==0)_v=umod();_v--;return *this;}mint operator++(int32_t){mint result=*this;++*this;return result;}mint operator--(int32_t){mint result=*this;--*this;return result;}mint&operator+=(const mint&rhs){_v+=rhs._v;if(_v>=umod()){_v-=umod();}return *this;}mint&operator-=(const mint&rhs){_v+=mod()-rhs._v;if(_v>=umod())_v-=umod();return *this;}mint&operator*=(const mint&rhs){_v=bt.mul(_v,rhs._v);return *this;}mint&operator/=(const mint&rhs){return *this=*this*rhs.inv();}mint operator+()const{return *this;}mint operator-()const{return mint()- *this;}mint pow(int n)const{assert(0<=n);mint x=*this,r=1;while(n){if(n&1)r*=x;x*=x;n>>=1;}return r;}mint inv()const{auto eg=internal::inv_gcd(_v,mod());assert(eg.first==1);return eg.second;}friend mint operator+(const mint&lhs,const mint&rhs){return mint(lhs)+=rhs;}friend mint operator-(const mint&lhs,const mint&rhs){return mint(lhs)-=rhs;}friend mint operator*(const mint&lhs,const mint&rhs){return mint(lhs)*=rhs;}friend mint operator/(const mint&lhs,const mint&rhs){return mint(lhs)/=rhs;}friend bool operator==(const mint&lhs,const mint&rhs){return lhs._v==rhs._v;}friend bool operator!=(const mint&lhs,const mint&rhs){return lhs._v!=rhs._v;}private:unsigned int _v;static internal::barrett bt;static unsigned int umod(){ return bt.umod(); }};template<int id>internal::barrett dynamic_modint<id>::bt(998244353);using modint998244353=static_modint<998244353>;using modint1000000007=static_modint<1000000007>;using modint=dynamic_modint<-1>;namespace internal{template<class T>using is_static_modint=std::is_base_of<internal::static_modint_base,T>;template<class T>using is_static_modint_t=std::enable_if_t<is_static_modint<T>::value>;template<class> struct is_dynamic_modint:public std::false_type{};template<int id>struct is_dynamic_modint<dynamic_modint<id>>:public std::true_type{};template<class T>using is_dynamic_modint_t=std::enable_if_t<is_dynamic_modint<T>::value>;}}
Full code (too long)
namespace atcoder {
namespace internal {
#ifndef _MSC_VER
template <class T>
using is_signed_int128 =
typename std::conditional<std::is_same<T, __int128_t>::value ||
std::is_same<T, __int128>::value,
std::true_type,
std::false_type>::type;
template <class T>
using is_unsigned_int128 =
typename std::conditional<std::is_same<T, __uint128_t>::value ||
std::is_same<T, unsigned __int128>::value,
std::true_type,
std::false_type>::type;
template <class T>
using make_unsigned_int128 =
typename std::conditional<std::is_same<T, __int128_t>::value,
__uint128_t,
unsigned __int128>;
template <class T>
using is_integral = typename std::conditional<std::is_integral<T>::value ||
is_signed_int128<T>::value ||
is_unsigned_int128<T>::value,
std::true_type,
std::false_type>::type;
template <class T>
using is_signed_int = typename std::conditional<(is_integral<T>::value &&
std::is_signed<T>::value) ||
is_signed_int128<T>::value,
std::true_type,
std::false_type>::type;
template <class T>
using is_unsigned_int =
typename std::conditional<(is_integral<T>::value &&
std::is_unsigned<T>::value) ||
is_unsigned_int128<T>::value,
std::true_type,
std::false_type>::type;
template <class T>
using to_unsigned = typename std::conditional<
is_signed_int128<T>::value,
make_unsigned_int128<T>,
typename std::conditional<std::is_signed<T>::value,
std::make_unsigned<T>,
std::common_type<T>>::type>::type;
#else
template <class T> using is_integral = typename std::is_integral<T>;
template <class T>
using is_signed_int =
typename std::conditional<is_integral<T>::value && std::is_signed<T>::value,
std::true_type,
std::false_type>::type;
template <class T>
using is_unsigned_int =
typename std::conditional<is_integral<T>::value &&
std::is_unsigned<T>::value,
std::true_type,
std::false_type>::type;
template <class T>
using to_unsigned = typename std::conditional<is_signed_int<T>::value,
std::make_unsigned<T>,
std::common_type<T>>::type;
#endif
template <class T>
using is_signed_int_t = std::enable_if_t<is_signed_int<T>::value>;
template <class T>
using is_unsigned_int_t = std::enable_if_t<is_unsigned_int<T>::value>;
template <class T> using to_unsigned_t = typename to_unsigned<T>::type;
constexpr long long safe_mod(long long x, long long m) {
x %= m;
if (x < 0) x += m;
return x;
}
struct barrett {
unsigned int _m;
unsigned long long im;
// @param m `1 <= m`
explicit barrett(unsigned int m) : _m(m), im((unsigned long long)(-1) / m + 1) {}
// @return m
unsigned int umod() const { return _m; }
// @param a `0 <= a < m`
// @param b `0 <= b < m`
// @return `a * b % m`
unsigned int mul(unsigned int a, unsigned int b) const {
// [1] m = 1
// a = b = im = 0, so okay
// [2] m >= 2
// im = ceil(2^64 / m)
// -> im * m = 2^64 + r (0 <= r < m)
// let z = a*b = c*m + d (0 <= c, d < m)
// a*b * im = (c*m + d) * im = c*(im*m) + d*im = c*2^64 + c*r + d*im
// c*r + d*im < m * m + m * im < m * m + 2^64 + m <= 2^64 + m * (m + 1) < 2^64 * 2
// ((ab * im) >> 64) == c or c + 1
unsigned long long z = a;
z *= b;
#ifdef _MSC_VER
unsigned long long x;
_umul128(z, im, &x);
#else
unsigned long long x =
(unsigned long long)(((unsigned __int128)(z)*im) >> 64);
#endif
unsigned long long y = x * _m;
return (unsigned int)(z - y + (z < y ? _m : 0));
}
};
constexpr std::pair<long long, long long> inv_gcd(long long a, long long b) {
a = safe_mod(a, b);
if (a == 0) return {b, 0};
// Contracts:
// [1] s - m0 * a = 0 (mod b)
// [2] t - m1 * a = 0 (mod b)
// [3] s * |m1| + t * |m0| <= b
long long s = b, t = a;
long long m0 = 0, m1 = 1;
while (t) {
long long u = s / t;
s -= t * u;
m0 -= m1 * u; // |m1 * u| <= |m1| * s <= b
// [3]:
// (s - t * u) * |m1| + t * |m0 - m1 * u|
// <= s * |m1| - t * u * |m1| + t * (|m0| + |m1| * u)
// = s * |m1| + t * |m0| <= b
auto tmp = s;
s = t;
t = tmp;
tmp = m0;
m0 = m1;
m1 = tmp;
}
// by [3]: |m0| <= b/g
// by g != b: |m0| < b/g
if (m0 < 0) m0 += b / s;
return {s, m0};
}
constexpr long long pow_mod_constexpr(long long x, long long n, int m) {
if (m == 1) return 0;
unsigned int _m = (unsigned int)(m);
unsigned long long r = 1;
unsigned long long y = safe_mod(x, m);
while (n) {
if (n & 1) r = (r * y) % _m;
y = (y * y) % _m;
n >>= 1;
}
return r;
}
constexpr bool is_prime_constexpr(int n) {
if (n <= 1) return false;
if (n == 2 || n == 7 || n == 61) return true;
if (n % 2 == 0) return false;
long long d = n - 1;
while (d % 2 == 0) d /= 2;
constexpr long long bases[3] = {2, 7, 61};
for (long long a : bases) {
long long t = d;
long long y = pow_mod_constexpr(a, t, n);
while (t != n - 1 && y != 1 && y != n - 1) {
y = y * y % n;
t <<= 1;
}
if (y != n - 1 && t % 2 == 0) {
return false;
}
}
return true;
}
template <int n> constexpr bool is_prime = is_prime_constexpr(n);
struct modint_base {};
struct static_modint_base : modint_base {};
template <class T> using is_modint = std::is_base_of<modint_base, T>;
template <class T> using is_modint_t = std::enable_if_t<is_modint<T>::value>;
} // namespace internal
template <int m, std::enable_if_t<(1 <= m)>* = nullptr>
struct static_modint : internal::static_modint_base {
using mint = static_modint;
public:
static constexpr int mod() { return m; }
static mint raw(int v) {
mint x;
x._v = v;
return x;
}
static_modint() : _v(0) {}
template <class T, internal::is_signed_int_t<T>* = nullptr>
static_modint(T v) {
long long x = (long long)(v % (long long)(umod()));
if (x < 0) x += umod();
_v = (unsigned int)(x);
}
template <class T, internal::is_unsigned_int_t<T>* = nullptr>
static_modint(T v) {
_v = (unsigned int)(v % umod());
}
unsigned int val() const { return _v; }
mint& operator++() {
_v++;
if (_v == umod()) _v = 0;
return *this;
}
mint& operator--() {
if (_v == 0) _v = umod();
_v--;
return *this;
}
mint operator++(int32_t) {
mint result = *this;
++*this;
return result;
}
mint operator--(int32_t) {
mint result = *this;
--*this;
return result;
}
mint& operator+=(const mint& rhs) {
_v += rhs._v;
if (_v >= umod()) _v -= umod();
return *this;
}
mint& operator-=(const mint& rhs) {
_v -= rhs._v;
if (_v >= umod()) _v += umod();
return *this;
}
mint& operator*=(const mint& rhs) {
unsigned long long z = _v;
z *= rhs._v;
_v = (unsigned int)(z % umod());
return *this;
}
mint& operator/=(const mint& rhs) { return *this = *this * rhs.inv(); }
mint operator+() const { return *this; }
mint operator-() const { return mint() - *this; }
mint pow(long long n) const {
assert(0 <= n);
mint x = *this, r = 1;
while (n) {
if (n & 1) r *= x;
x *= x;
n >>= 1;
}
return r;
}
mint inv() const {
if (prime) {
assert(_v);
return pow(umod() - 2);
} else {
auto eg = internal::inv_gcd(_v, m);
assert(eg.first == 1);
return eg.second;
}
}
friend mint operator+(const mint& lhs, const mint& rhs) {
return mint(lhs) += rhs;
}
friend mint operator-(const mint& lhs, const mint& rhs) {
return mint(lhs) -= rhs;
}
friend mint operator*(const mint& lhs, const mint& rhs) {
return mint(lhs) *= rhs;
}
friend mint operator/(const mint& lhs, const mint& rhs) {
return mint(lhs) /= rhs;
}
friend bool operator==(const mint& lhs, const mint& rhs) {
return lhs._v == rhs._v;
}
friend bool operator!=(const mint& lhs, const mint& rhs) {
return lhs._v != rhs._v;
}
private:
unsigned int _v;
static constexpr unsigned int umod() { return m; }
static constexpr bool prime = internal::is_prime<m>;
};
template <int id> struct dynamic_modint : internal::modint_base {
using mint = dynamic_modint;
public:
static int mod() { return (int)(bt.umod()); }
static void set_mod(int m) {
assert(1 <= m);
bt = internal::barrett(m);
}
static mint raw(int v) {
mint x;
x._v = v;
return x;
}
dynamic_modint() : _v(0) {}
template <class T, internal::is_signed_int_t<T>* = nullptr>
dynamic_modint(T v) {
long long x = (long long)(v % (long long)(mod()));
if (x < 0) x += mod();
_v = (unsigned int)(x);
}
template <class T, internal::is_unsigned_int_t<T>* = nullptr>
dynamic_modint(T v) {
_v = (unsigned int)(v % mod());
}
unsigned int val() const { return _v; }
mint& operator++() {
_v++;
if (_v == umod()) _v = 0;
return *this;
}
mint& operator--() {
if (_v == 0) _v = umod();
_v--;
return *this;
}
mint operator++(int32_t) {
mint result = *this;
++*this;
return result;
}
mint operator--(int32_t) {
mint result = *this;
--*this;
return result;
}
mint& operator+=(const mint& rhs) {
_v += rhs._v;
if (_v >= umod()) _v -= umod();
return *this;
}
mint& operator-=(const mint& rhs) {
_v += mod() - rhs._v;
if (_v >= umod()) _v -= umod();
return *this;
}
mint& operator*=(const mint& rhs) {
_v = bt.mul(_v, rhs._v);
return *this;
}
mint& operator/=(const mint& rhs) { return *this = *this * rhs.inv(); }
mint operator+() const { return *this; }
mint operator-() const { return mint() - *this; }
mint pow(long long n) const {
assert(0 <= n);
mint x = *this, r = 1;
while (n) {
if (n & 1) r *= x;
x *= x;
n >>= 1;
}
return r;
}
mint inv() const {
auto eg = internal::inv_gcd(_v, mod());
assert(eg.first == 1);
return eg.second;
}
friend mint operator+(const mint& lhs, const mint& rhs) {
return mint(lhs) += rhs;
}
friend mint operator-(const mint& lhs, const mint& rhs) {
return mint(lhs) -= rhs;
}
friend mint operator*(const mint& lhs, const mint& rhs) {
return mint(lhs) *= rhs;
}
friend mint operator/(const mint& lhs, const mint& rhs) {
return mint(lhs) /= rhs;
}
friend bool operator==(const mint& lhs, const mint& rhs) {
return lhs._v == rhs._v;
}
friend bool operator!=(const mint& lhs, const mint& rhs) {
return lhs._v != rhs._v;
}
private:
unsigned int _v;
static internal::barrett bt;
static unsigned int umod() { return bt.umod(); }
};
template <int id> internal::barrett dynamic_modint<id>::bt(998244353);
using modint998244353 = static_modint<998244353>;
using modint1000000007 = static_modint<1000000007>;
using modint = dynamic_modint<-1>;
namespace internal {
template <class T>
using is_static_modint = std::is_base_of<internal::static_modint_base, T>;
template <class T>
using is_static_modint_t = std::enable_if_t<is_static_modint<T>::value>;
template <class> struct is_dynamic_modint : public std::false_type {};
template <int id>
struct is_dynamic_modint<dynamic_modint<id>> : public std::true_type {};
template <class T>
using is_dynamic_modint_t = std::enable_if_t<is_dynamic_modint<T>::value>;
} // namespace internal
} // namespace atcoder