Language: C++

//#define NDEBUG
#include <cstddef>
#include <cstdint>
#include <iostream>
#include <vector>

namespace n91 {

using i8 = std::int_fast8_t;
using i32 = std::int_fast32_t;
using i64 = std::int_fast64_t;
using u8 = std::uint_fast8_t;
using u32 = std::uint_fast32_t;
using u64 = std::uint_fast64_t;
using isize = std::ptrdiff_t;
using usize = std::size_t;

constexpr usize operator"" _z(unsigned long long x) noexcept {
  return static_cast<usize>(x);
}

class rep {
  const usize f, l;

public:
  class itr {
    friend rep;
    usize i;
    constexpr itr(const usize x) noexcept : i(x) {}

  public:
    void operator++() noexcept { ++i; }
    constexpr usize operator*() const noexcept { return i; }
    constexpr bool operator!=(const itr x) const noexcept { return i != x.i; }
  };
  constexpr rep(const usize first, const usize last) noexcept
      : f(first), l(last) {}
  constexpr itr begin() const noexcept { return itr(f); }
  constexpr itr end() const noexcept { return itr(l); }
};
class revrep {
  const usize f, l;

public:
  class itr {
    friend revrep;
    usize i;
    constexpr itr(usize x) noexcept : i(x) {}

  public:
    void operator++() noexcept { --i; }
    constexpr usize operator*() const noexcept { return i; }
    constexpr bool operator!=(const itr x) const noexcept { return i != x.i; }
  };
  constexpr revrep(usize first, usize last) noexcept : f(--first), l(--last) {}
  constexpr itr begin() const noexcept { return itr(l); }
  constexpr itr end() const noexcept { return itr(f); }
};
template <class T> using vec_alias = std::vector<T>;
template <class T> auto md_vec(const usize n, const T &value) {
  return std::vector<T>(n, value);
}
template <class... Args> auto md_vec(const usize n, Args... args) {
  return std::vector<decltype(md_vec(args...))>(n, md_vec(args...));
}
template <class T> constexpr T difference(const T &a, const T &b) {
  return a < b ? b - a : a - b;
}
template <class T> T scan() {
  T ret;
  std::cin >> ret;
  return ret;
}

} // namespace n91

#include <cstdint>
#include <vector>

namespace n91 {

template <class Base> struct m2e61m1_rolling_hash {
  using u64 = std::uint_fast64_t;
  using value_type = u64;
  using container_type = std::vector<value_type>;
  using size_type = typename container_type::size_type;

  static constexpr u64 mask2(const int exp) noexcept {
    return (static_cast<u64>(1) << exp) - static_cast<u64>(1);
  }

  static constexpr u64 Mod = pow2(61) - static_cast<u64>(1);

  static constexpr u64 cyclic(const u64 v) noexcept {
    return ((v & mask2(30)) << 31) + (v >> 30);
  }
  static constexpr u64 calc(u64 v) noexcept {
    if (v > Mod) {
      v = (v & mask2(61)) + (v >> 61);
    }
    if (v > Mod) {
      return v -= Mod;
    }
    return Mod;
  }
  static constexpr u64 multiplies(const u64 l, const u64 r) noexcept {
    /*
    using t = __int128;
    return t(l) * t(r) % t(Mod);
    /*/
    const u64 lu = l >> 31, ld = l & mask2(31), ru = r >> 31,
              rd = r & mask2(31);

    return calc((lu * ru << 1) + ld * rd + cyclic(lu * rd + ru * ld));
    //*/
  }
  static constexpr u64 multiplies_plus(const u64 l, const u64 r,
                                       const u64 c) noexcept {
    /*
    using t = __int128;
    return (t(l) * t(r) + t(c)) % t(Mod);
    /*/
    const u64 lu = l >> 31, ld = l & mask2(31), ru = r >> 31,
              rd = r & mask2(31);

    return calc((lu * ru << 1) + ld * rd + cyclic(lu * rd + ru * ld) + c);
    //*/
  }

  container_type prefix, power;

public:
  template <class InputIterator>
  explicit m2e61m1_rolling_hash(InputIterator first,
                                const InputIterator last) noexcept
      : prefix(), power() {
    const size_type n = static_cast<size_type>(std::distance(first, last));
    prefix.reserve(n + static_cast<size_type>(1));
    prefix.push_back(static_cast<value_type>(0));
    for (; first != last; ++first) {
      prefix.push_back(multiplies_plus(prefix.back(), Base::value, *first));
    }
    power.reserve(n + static_cast<size_type>(1));
    power.push_back(static_cast<value_type>(1));
    for (size_type i = static_cast<size_type>(0); i != n; ++i) {
      power.push_back(multiplies(power.back(), Base::value));
    }
  }

  value_type operator()(const size_type first, const size_type last) const
      noexcept {
    return multiplies_plus(prefix[first], power[last - first],
                           Mod - prefix[last]);
  }
};

} // namespace n91

#include <algorithm>
#include <array>
#include <iostream>
#include <string>
#include <utility>

namespace n91 {

void main_() {
  using hash = m2e61m1_rolling_hash<std::integral_constant<u64, 62479294>>;
  auto s = scan<std::string>();
  const auto t = scan<std::string>();
  const usize m = t.size();
  while (s.size() < m) {
    s = s + s;
  }
  const usize n = s.size();
  s = s + s;
  const hash sh(s.cbegin(), s.cend());
  const u64 th = hash(t.cbegin(), t.cend())(0_z, m);
  std::vector<usize> next(n, n), prev(n, n);
  for (const auto i : rep(0_z, n)) {
    if (sh(i, i + m) == th) {
      next[i] = (i + m) % n;
      prev[next[i]] = i;
    }
  }
  usize r_cnt = 0_z;
  usize ans = 0_z;
  for (const auto i : rep(0_z, n)) {
    if (prev[i] == n) {
      ++r_cnt;
      usize count = 0_z;
      usize v = next[i];
      while (v != n) {
        ++r_cnt;
        v = next[v];
        ++count;
      }
      ans = std::max(ans, count);
    }
  }
  if (r_cnt == n) {
    std::cout << ans << std::endl;
  } else {
    std::cout << "-1" << std::endl;
  }
}

} // namespace n91

int main() {
  n91::main_();
  return 0;
}


Compiler output:
a.cc:92:30: error: there are no arguments to 'pow2' that depend on a template parameter, so a declaration of 'pow2' must be available [-fpermissive]
   92 |   static constexpr u64 Mod = pow2(61) - static_cast<u64>(1);
      |                              ^~~~
a.cc:92:30: note: (if you use '-fpermissive', G++ will accept your code, but allowing the use of an undeclared name is deprecated)
a.cc: In instantiation of 'constexpr const n91::m2e61m1_rolling_hash<std::integral_constant<long unsigned int, 62479294> >::u64 n91::m2e61m1_rolling_hash<std::integral_constant<long unsigned int, 62479294> >::Mod':
a.cc:153:28:   required from 'n91::m2e61m1_rolling_hash<Base>::value_type n91::m2e61m1_rolling_hash<Base>::operator()(size_type, size_type) const [with Base = std::integral_constant<long unsigned int, 62479294>; value_type = long unsigned int; size_type = long unsigned int]'
  153 |                            Mod - prefix[last]);
      |                            ^~~
a.cc:178:44:   required from here
  178 |   const u64 th = hash(t.cbegin(), t.cend())(0_z, m);
      |                  ~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~
a.cc:92:34: error: 'pow2' was not declared in this scope
   92 |   static constexpr u64 Mod = pow2(61) - static_cast<u64>(1);
      |                              ~~~~^~~~