alg/monoid/rollinghash.hpp

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Last update: 2023-12-22 20:53:57+09:00
Include: #include "alg/monoid/rollinghash.hpp"

Depends on

Verified with

test/library_checker/string/zalgorithm_by_rollinghash2.test.cpp

Code

#pragma once

#include "random/base.hpp"

#include "mod/modint61.hpp"


// pow of base, val

struct Monoid_Rolling_Hash {
  using value_type = pair<modint61, modint61>;
  using X = value_type;

  static u64 &get_param() {
    static u64 base = 0;
    return base;
  }
  static void set_param(u64 base) { get_param() = base; }

  static X from_element(u64 x) {
    while (get_param() == 0) set_param(RNG_64());
    return {get_param(), x};
  }
  static X op(X x, X y) { return {x.fi * y.fi, x.se * y.fi + y.se}; }
  static constexpr X unit() { return {1, 0}; }
  static constexpr bool commute = false;
};

#line 2 "alg/monoid/rollinghash.hpp"

#line 2 "random/base.hpp"

u64 RNG_64() {
  static uint64_t x_
      = uint64_t(chrono::duration_cast<chrono::nanoseconds>(
                     chrono::high_resolution_clock::now().time_since_epoch())
                     .count())
        * 10150724397891781847ULL;
  x_ ^= x_ << 7;
  return x_ ^= x_ >> 9;
}

u64 RNG(u64 lim) { return RNG_64() % lim; }

ll RNG(ll l, ll r) { return l + RNG_64() % (r - l); }
#line 2 "mod/modint61.hpp"

struct modint61 {
  static constexpr u64 mod = (1ULL << 61) - 1;
  u64 val;
  constexpr modint61() : val(0ULL) {}
  constexpr modint61(u32 x) : val(x) {}
  constexpr modint61(u64 x) : val(x % mod) {}
  constexpr modint61(int x) : val((x < 0) ? (x + static_cast<ll>(mod)) : x) {}
  constexpr modint61(ll x)
      : val(((x %= static_cast<ll>(mod)) < 0) ? (x + static_cast<ll>(mod))
                                              : x) {}
  static constexpr u64 get_mod() { return mod; }
  modint61 &operator+=(const modint61 &a) {
    val = ((val += a.val) >= mod) ? (val - mod) : val;
    return *this;
  }
  modint61 &operator-=(const modint61 &a) {
    val = ((val -= a.val) >= mod) ? (val + mod) : val;
    return *this;
  }
  modint61 &operator*=(const modint61 &a) {
    const unsigned __int128 y = static_cast<unsigned __int128>(val) * a.val;
    val = (y >> 61) + (y & mod);
    val = (val >= mod) ? (val - mod) : val;
    return *this;
  }
  modint61 operator-() const { return modint61(val ? mod - val : u64(0)); }
  modint61 &operator/=(const modint61 &a) { return (*this *= a.inverse()); }
  modint61 operator+(const modint61 &p) const { return modint61(*this) += p; }
  modint61 operator-(const modint61 &p) const { return modint61(*this) -= p; }
  modint61 operator*(const modint61 &p) const { return modint61(*this) *= p; }
  modint61 operator/(const modint61 &p) const { return modint61(*this) /= p; }
  bool operator==(const modint61 &p) const { return val == p.val; }
  bool operator!=(const modint61 &p) const { return val != p.val; }
  modint61 inverse() const {
    ll a = val, b = mod, u = 1, v = 0, t;
    while (b > 0) {
      t = a / b;
      swap(a -= t * b, b), swap(u -= t * v, v);
    }
    return modint61(u);
  }
  modint61 pow(ll n) const {
    assert(n >= 0);
    modint61 ret(1), mul(val);
    while (n > 0) {
      if (n & 1) ret *= mul;
      mul *= mul, n >>= 1;
    }
    return ret;
  }
};

#ifdef FASTIO
void rd(modint61 &x) {
  fastio::rd(x.val);
  assert(0 <= x.val && x.val < modint61::mod);
}

void wt(modint61 x) { fastio::wt(x.val); }
#endif
#line 5 "alg/monoid/rollinghash.hpp"

// pow of base, val

struct Monoid_Rolling_Hash {
  using value_type = pair<modint61, modint61>;
  using X = value_type;

  static u64 &get_param() {
    static u64 base = 0;
    return base;
  }
  static void set_param(u64 base) { get_param() = base; }

  static X from_element(u64 x) {
    while (get_param() == 0) set_param(RNG_64());
    return {get_param(), x};
  }
  static X op(X x, X y) { return {x.fi * y.fi, x.se * y.fi + y.se}; }
  static constexpr X unit() { return {1, 0}; }
  static constexpr bool commute = false;
};