cp-library-cpp
This documentation is automatically generated by online-judge-tools/verification-helper
test/string/rolling_hash/2.test.cpp
- View this file on GitHub
- Last update: 2021-08-15 20:56:58+09:00
- Problem: https://atcoder.jp/contests/abc141/tasks/abc141_e
Depends on
Code
#define PROBLEM "https://atcoder.jp/contests/abc141/tasks/abc141_e"
#include <algorithm>
#include <iostream>
#include <string>
#define CP_LIBRARY_ROLLING_HASH_MAX_LENGTH 5000
#include "../../../include/string/rolling_hash.hpp"
int main() {
int N, res = 0;
std::string S;
std::cin >> N >> S;
const auto S_hash = lib::get_rolling_hash(S);
for (int i = 0; i < N; ++i) {
for (int j = i + 1; j < N; ++j) {
int tmp = res;
while (true) {
if (i + tmp >= j || j + tmp >= N)
break;
if (S_hash.substring(i, tmp + 1) != S_hash.substring(j, tmp + 1))
break;
++tmp;
}
res = std::max(res, tmp);
}
}
std::cout << res << '\n';
}#line 1 "test/string/rolling_hash/2.test.cpp"
#define PROBLEM "https://atcoder.jp/contests/abc141/tasks/abc141_e"
#include <algorithm>
#include <iostream>
#include <string>
#define CP_LIBRARY_ROLLING_HASH_MAX_LENGTH 5000
#line 1 "include/string/rolling_hash.hpp"
//! @file rolling_hash.hpp
//! @note The implementation is based on this article https://qiita.com/keymoon/items/11fac5627672a6d6a9f6
#ifndef CP_LIBRARY_ROLLING_HASH_HPP
#define CP_LIBRARY_ROLLING_HASH_HPP
#ifndef CP_LIBRARY_ROLLING_HASH_MAX_LENGTH
# warning Please define CP_LIBRARY_ROLLING_HASH_MAX_LENGTH (default: 200000).
# define CP_LIBRARY_ROLLING_HASH_MAX_LENGTH 200000
# define CP_LIBRARY_ROLLING_HASH_MAX_LENGTH_NOT_DEFINED
#endif
#line 15 "include/string/rolling_hash.hpp"
#include <array>
#include <cassert>
#include <cstdint>
#line 19 "include/string/rolling_hash.hpp"
#include <limits>
#line 21 "include/string/rolling_hash.hpp"
#include <tuple>
#include <vector>
#ifndef CP_LIBRARY_ASSERT
//! @brief Assert macro
# define CP_LIBRARY_ASSERT(...) assert(__VA_ARGS__)
# define CP_LIBRARY_ASSERT_NOT_DEFINED
#endif
#ifndef CP_LIBRARY_ERROR
# if (CP_LIBRARY_DEBUG_LEVEL >= 2)
//! @brief Print error message and exit
# define CP_LIBRARY_ERROR(...) \
do { \
__VA_ARGS__ \
CP_LIBRARY_ASSERT(false); \
} while (false)
# else
//! @brief Abort the program
# define CP_LIBRARY_ERROR(...) CP_LIBRARY_ASSERT(false)
# endif
# define CP_LIBRARY_ERROR_NOT_DEFINED
#endif
namespace lib {
namespace internal::rolling_hash_hpp {
using u64 = std::uint_least64_t;
template <unsigned index>
constexpr u64 mask = (u64(1) << index) - 1;
template <unsigned index>
constexpr u64 pad = mask<index>* mask<std::numeric_limits<u64>::digits - index>;
[[gnu::const]] [[nodiscard]] constexpr u64 mod_mersenne_61(const u64 x) noexcept {
if (const u64 res = (x >> 61) + (x & mask<61>); res >= mask<61>)
return res - mask<61>;
else
return res;
}
[[gnu::const]] [[nodiscard]] constexpr u64 mult(const u64 x, const u64 y) noexcept {
const u64 x_upper = (x >> 31);
const u64 x_lower = (x & mask<31>);
const u64 y_upper = (y >> 31);
const u64 y_lower = (y & mask<31>);
const u64 z = x_upper * y_lower + x_lower * y_upper;
return ((x_upper * y_upper) << 1) + (z >> 30) + ((z & mask<30>) << 31) + (x_lower * y_lower);
}
template <u64 base>
[[nodiscard]] u64 pow_mod_mersenne_61(unsigned index) {
static bool first = true;
static std::array<u64, CP_LIBRARY_ROLLING_HASH_MAX_LENGTH + 1> res;
if (__builtin_expect(first, 0)) {
first = false;
res[0] = 1;
for (unsigned i = 1; i <= CP_LIBRARY_ROLLING_HASH_MAX_LENGTH; ++i)
res[i] = mod_mersenne_61(mult(res[i - 1], base));
}
return res[index];
}
template <class TupleType, std::size_t... Is>
void print_tuple(const TupleType& arg, std::ostream& os, std::index_sequence<Is...>) {
static_cast<void>(((os << (Is == 0 ? "" : ", "), (os << std::get<Is>(arg))), ...));
}
// Using the following type alias unables GCC to compile the code. (no problem with Clang/MSVC. maybe a bug.)
// template <std::uint32_t... Bases>
// using hash_t = decltype(std::tuple {(static_cast<u64>(Bases))...});
// See: https://wandbox.org/permlink/xpqiYobUkI1EGpgo (on GCC 12.0.0)
// https://wandbox.org/permlink/26ZTzuIfTivSz2lR (on Clang 13.0.0)
// ToDo: Replace decltype(std::tuple {(static_cast<u64>(Bases))...}) with hash_t<Bases...>
// and replace decltype(std::tuple {(static_cast<internal::rolling_hash_hpp::u64>(Bases))...}) with internal::rolling_hash_hpp::hash_t<Bases...>
// when we figure out the workaround or this bug(?) is fixed.
template <std::uint32_t... Bases, typename Container, std::size_t... Is>
void build_hash_sequence_impl(const Container& src,
std::vector<decltype(std::tuple {(static_cast<u64>(Bases))...})>& dest,
std::index_sequence<Is...>) {
constexpr std::tuple bases_tuple = std::tuple {Bases...};
const std::size_t size = std::size(src);
auto iter = std::cbegin(src);
for (std::size_t i = 0; i < size; ++iter, ++i)
static_cast<void>(((std::get<Is>(dest[i + 1]) = mod_mersenne_61(mult(std::get<Is>(dest[i]), std::get<Is>(bases_tuple)) + static_cast<u64>(*iter))), ...));
}
template <std::uint32_t... Bases, typename Container>
[[nodiscard]] std::vector<decltype(std::tuple {(static_cast<u64>(Bases))...})> build_hash_sequence(const Container& src) {
std::vector<decltype(std::tuple {(static_cast<u64>(Bases))...})> res(std::size(src) + 1);
build_hash_sequence_impl<Bases...>(src, res, std::make_index_sequence<sizeof...(Bases)> {});
return res;
}
template <std::uint32_t... Bases, std::size_t... Is>
[[nodiscard]] constexpr decltype(std::tuple {(static_cast<u64>(Bases))...}) substr_hash_impl(const std::vector<decltype(std::tuple {(static_cast<u64>(Bases))...})>& hashes, const int starts, const int length, std::index_sequence<Is...>) {
constexpr std::tuple bases_tuple = std::tuple {Bases...};
decltype(std::tuple {(static_cast<u64>(Bases))...}) res;
static_cast<void>(((std::get<Is>(res) = mod_mersenne_61(std::get<Is>(hashes[starts + length]) + pad<61> - mod_mersenne_61(mult(std::get<Is>(hashes[starts]), pow_mod_mersenne_61<std::get<Is>(bases_tuple)>(length))))), ...));
return res;
}
template <std::uint32_t... Bases>
[[nodiscard]] constexpr decltype(std::tuple {(static_cast<u64>(Bases))...}) substr_hash(const std::vector<decltype(std::tuple {(static_cast<u64>(Bases))...})>& hashes, const int starts, const int length) {
return substr_hash_impl<Bases...>(hashes, starts, length, std::make_index_sequence<sizeof...(Bases)> {});
}
} // namespace internal::rolling_hash_hpp
#if (CP_LIBRARY_DEBUG_LEVEL >= 2)
template <typename Elem, std::uint32_t... Bases>
class rolling_hash {
private:
static constexpr std::tuple bases_tuple {Bases...};
std::vector<Elem> src;
std::vector<decltype(std::tuple {(static_cast<internal::rolling_hash_hpp::u64>(Bases))...})> hashes;
struct single_hash {
private:
std::vector<Elem> src;
decltype(std::tuple {(static_cast<internal::rolling_hash_hpp::u64>(Bases))...}) val;
int length;
template <std::size_t... Is>
[[nodiscard]] auto concat_impl(const single_hash& rhs, std::index_sequence<Is...>) const {
single_hash res;
res.src = src;
res.src.insert(std::end(res.src), std::cbegin(rhs.src), std::cend(rhs.src));
res.length = length + rhs.length;
static_cast<void>(((std::get<Is>(res.val) = internal::rolling_hash_hpp::mod_mersenne_61(internal::rolling_hash_hpp::mod_mersenne_61(internal::rolling_hash_hpp::mult(std::get<Is>(val), internal::rolling_hash_hpp::pow_mod_mersenne_61<std::get<Is>(bases_tuple)>(rhs.length))) + std::get<Is>(rhs.val))), ...));
return res;
}
template <std::size_t... Is>
void concat_self_impl(const single_hash& rhs, std::index_sequence<Is...>) {
src.insert(std::end(src), std::cbegin(rhs.src), std::cend(rhs.src));
length += rhs.length;
static_cast<void>(((std::get<Is>(val) = internal::rolling_hash_hpp::mod_mersenne_61(internal::rolling_hash_hpp::mod_mersenne_61(internal::rolling_hash_hpp::mult(std::get<Is>(val), internal::rolling_hash_hpp::pow_mod_mersenne_61<std::get<Is>(bases_tuple)>(rhs.length))) + std::get<Is>(rhs.val))), ...));
}
public:
//! @brief Construct empty single_hash object.
//! @note Time complexity: O(number of bases), which can be regarded as constant time
constexpr single_hash() noexcept
: val(), length() {}
//! @brief Construct singli_hash object from hash value and size.
//! @note Time complexity: O(number of bases), which can be regarded as constant time
single_hash(const std::vector<Elem>& source, const decltype(std::tuple {(static_cast<internal::rolling_hash_hpp::u64>(Bases))...})& hash, const int size)
: src(source), val(hash), length(size) {}
//! @brief Construct singli_hash object from hash value and size.
//! @note Time complexity: O(number of bases), which can be regarded as constant time
single_hash(std::vector<Elem>&& source, decltype(std::tuple {(static_cast<internal::rolling_hash_hpp::u64>(Bases))...})&& hash, const int size)
: src(std::move(source)), val(std::move(hash)), length(size) {}
//! @return The length of the sequence
//! @note Time complexity: O(1)
[[nodiscard]] int size() const noexcept {
return length;
}
//! @return Whether both sides are the same sequence
//! @param rhs another sequence
//! @note Time complexity: O(size) since you are in debugging mode
[[nodiscard]] bool operator==(const single_hash& rhs) const {
const bool res = (val == rhs.val);
const bool precise_res = (src == rhs.src);
if (__builtin_expect(res != precise_res, 0)) {
CP_LIBRARY_ERROR(
const std::ios_base::fmtflags prev_state = std::cerr.flags();
std::cerr << "*** Hash collision detected ***\n"
<< "Hash value: (" << std::hex;
internal::rolling_hash_hpp::print_tuple(val, std::cerr, std::make_index_sequence<std::tuple_size_v<decltype(val)>> {});
std::cerr << ")\n\n";
std::cerr.flags(prev_state);
if constexpr (std::is_same_v<char, Elem>) {
std::cerr << "String 1: \"";
std::for_each(std::cbegin(src), std::cend(src), [](const char c) { std::cerr << c; });
std::cerr << "\"\n";
std::cerr << "String 2: \"";
std::for_each(std::cbegin(rhs.src), std::cend(rhs.src), [](const char c) { std::cerr << c; });
std::cerr << "\"\n\n";
} else {
std::cerr << "Sequence 1: [ ";
std::for_each(std::cbegin(src), std::cend(src), [](const Elem& e) { std::cerr << e << ' '; });
std::cerr << "]\n";
std::cerr << "Sequence 2: [ ";
std::for_each(std::cbegin(rhs.src), std::cend(rhs.src), [](const Elem& e) { std::cerr << e << ' '; });
std::cerr << "]\n\n";
});
}
return res;
}
//! @return Whether both sides are NOT the same sequence
//! @param rhs another sequence
//! @note Time complexity: O(number of bases), which can be regarded as constant time
[[nodiscard]] bool operator!=(const single_hash& rhs) const {
return !(*this == rhs);
}
//! @brief Concatenate two sequences.
//! @param rhs another sequence
//! @return Concatenated sequence
//! @note Time complexity: O(length of the resulting sequence) since you are in debugging mode
[[nodiscard]] single_hash operator+(const single_hash& rhs) const {
return concat_impl(rhs, std::make_index_sequence<std::tuple_size_v<decltype(bases_tuple)>> {});
}
//! @brief Append a sequence at the end.
//! @param rhs another sequence
//! @note Time complexity: O(length of rhs) since you are in debugging mode
single_hash& operator+=(const single_hash& rhs) {
concat_self_impl(rhs, std::make_index_sequence<std::tuple_size_v<decltype(bases_tuple)>> {});
return *this;
}
//! @return Hash value
//! @note The return value is not just an integer, but a tuple that contains multiple integers.
//! @note Time complexity: O(number of bases), which can be regarded as constant time
[[nodiscard]] auto hash_value() const noexcept {
return val;
}
//! @brief Print information for debugging if CP_LIBRARY_DEBUG_LEVEL >= 1 (which is satisfied)
void debug_print(const std::string& name = "", std::ostream& os = std::cerr) const {
if (!name.empty())
os << name << ": ";
if constexpr (std::is_same_v<char, Elem>) {
os << " String = \"";
std::for_each(std::cbegin(src), std::cend(src), [&](const char c) { os << c; });
os << "\"\n";
} else {
os << " Sequence = [ ";
std::for_each(std::cbegin(src), std::cend(src), [&](const Elem& e) { os << e << ' '; });
os << "]\n";
}
const std::ios_base::fmtflags prev_state = os.flags();
os << (name.empty() ? std::string() : std::string(std::size(name) + 2, ' '))
<< "Hash value = " << std::hex << '(';
internal::rolling_hash_hpp::print_tuple(val, os, std::make_index_sequence<std::tuple_size_v<decltype(val)>> {});
os << ")\n\n";
os.flags(prev_state);
}
};
public:
//! @brief Construct a rolling_hash object from source container.
//! @note Time complexity: O(length)
template <typename Container>
rolling_hash(const Container& source)
: src(std::cbegin(source), std::cend(source)), hashes(internal::rolling_hash_hpp::build_hash_sequence<Bases...>(src)) {}
//! @return The length of the sequence
[[nodiscard]] int size() const noexcept(noexcept(std::size(src))) {
return static_cast<int>(std::size(src));
}
//! @return An object that represents the hash value of the entire sequence
//! @note Time complexity: O(length) since you are in debugging mode
[[nodiscard]] single_hash whole_string() const {
return single_hash(src, hashes.back(), size());
}
//! @param starts The index where the substring starts (0-indexed)
//! @param length The length of the substring
//! @return An object that represents the hash value of the substring
//! @note Time complexity: O(length) since you are in debugging mode
[[nodiscard]] single_hash substring(const int starts, int length = std::numeric_limits<int>::max()) const {
length = std::min(static_cast<int>(std::size(src)) - starts, length);
return single_hash(std::vector<Elem>(std::cbegin(src) + starts, std::cbegin(src) + starts + length), internal::rolling_hash_hpp::substr_hash<Bases...>(hashes, starts, length), length);
}
};
#else
//! @brief Object that can quickly compute the hash value of a substring as well as the entire string.
//! @tparam Elem element type (e.g. char for std::string)
//! @tparam Bases base (radix) integers
template <typename Elem, std::uint32_t... Bases>
class rolling_hash {
private:
static constexpr std::tuple bases_tuple {Bases...};
std::vector<decltype(std::tuple {(static_cast<internal::rolling_hash_hpp::u64>(Bases))...})> hashes;
//! @brief Object that represents string hash.
struct single_hash {
private:
decltype(std::tuple {(static_cast<internal::rolling_hash_hpp::u64>(Bases))...}) val;
int length;
template <std::size_t... Is>
[[nodiscard]] auto concat_impl(const single_hash& rhs, std::index_sequence<Is...>) const {
single_hash res;
res.length = length + rhs.length;
static_cast<void>(((std::get<Is>(res.val) = internal::rolling_hash_hpp::mod_mersenne_61(internal::rolling_hash_hpp::mod_mersenne_61(internal::rolling_hash_hpp::mult(std::get<Is>(val), internal::rolling_hash_hpp::pow_mod_mersenne_61<std::get<Is>(bases_tuple)>(rhs.length))) + std::get<Is>(rhs.val))), ...));
return res;
}
template <std::size_t... Is>
void concat_self_impl(const single_hash& rhs, std::index_sequence<Is...>) {
length += rhs.length;
static_cast<void>(((std::get<Is>(val) = internal::rolling_hash_hpp::mod_mersenne_61(internal::rolling_hash_hpp::mod_mersenne_61(internal::rolling_hash_hpp::mult(std::get<Is>(val), internal::rolling_hash_hpp::pow_mod_mersenne_61<std::get<Is>(bases_tuple)>(rhs.length))) + std::get<Is>(rhs.val))), ...));
}
public:
//! @brief Construct empty single_hash object.
//! @note Time complexity: O(number of bases), which can be regarded as constant time
constexpr single_hash() noexcept
: val(), length() {}
//! @brief Construct singli_hash object from hash value and size.
//! @note Time complexity: O(number of bases), which can be regarded as constant time
single_hash(const decltype(std::tuple {(static_cast<internal::rolling_hash_hpp::u64>(Bases))...})& hash, const int size)
: val(hash), length(size) {}
//! @brief Construct singli_hash object from hash value and size.
//! @note Time complexity: O(number of bases), which can be regarded as constant time
single_hash(decltype(std::tuple {(static_cast<internal::rolling_hash_hpp::u64>(Bases))...})&& hash, const int size)
: val(std::move(hash)), length(size) {}
//! @return The length of the sequence
//! @note Time complexity: O(1)
[[nodiscard]] int size() const noexcept {
return length;
}
//! @param rhs another sequence
//! @return Whether both sides are the same sequence
//! @note Time complexity: O(number of bases), which can be regarded as constant time
[[nodiscard]] bool operator==(const single_hash& rhs) const noexcept {
return (length == rhs.length) && (val == rhs.val);
}
//! @param rhs another sequence
//! @return Whether both sides are NOT the same sequence
//! @note Time complexity: O(number of bases), which can be regarded as constant time
[[nodiscard]] bool operator!=(const single_hash& rhs) const noexcept {
return !(*this == rhs);
}
//! @brief Concatenate two sequences.
//! @param rhs another sequence
//! @return Concatenated sequence
//! @note Time complexity: O(number of bases), which can be regarded as constant time
[[nodiscard]] single_hash operator+(const single_hash& rhs) const {
return concat_impl(rhs, std::make_index_sequence<std::tuple_size_v<decltype(bases_tuple)>> {});
}
//! @brief Append a sequence at the end.
//! @param rhs another sequence
//! @note Time complexity: O(number of bases), which can be regarded as constant time
single_hash& operator+=(const single_hash& rhs) {
concat_self_impl(rhs, std::make_index_sequence<std::tuple_size_v<decltype(bases_tuple)>> {});
return *this;
}
//! @return Hash value
//! @note The return value is not just an integer, but a tuple that contains multiple integers.
//! @note Time complexity: O(number of bases), which can be regarded as constant time
[[nodiscard]] auto hash_value() const noexcept {
return val;
}
//! @brief Print information for debugging if CP_LIBRARY_DEBUG_LEVEL >= 1
void debug_print([[maybe_unused]] const std::string& name = "", [[maybe_unused]] std::ostream& os = std::cerr) const {
# if (CP_LIBRARY_DEBUG_LEVEL >= 1)
if (!name.empty())
os << name << ": ";
const std::ios_base::fmtflags prev_state = os.flags();
os << "Hash value = " << std::hex << '(';
internal::rolling_hash_hpp::print_tuple(val, os, std::make_index_sequence<std::tuple_size_v<decltype(val)>> {});
os << ")\n";
os.flags(prev_state);
# endif
}
};
public:
//! @brief Construct a rolling_hash object from source container.
//! @note Time complexity: O(length)
template <typename Container>
rolling_hash(const Container& source)
: hashes(internal::rolling_hash_hpp::build_hash_sequence<Bases...>(source)) {}
//! @return The length of the sequence
[[nodiscard]] int size() const noexcept(noexcept(std::size(hashes))) {
return static_cast<int>(std::size(hashes)) - 1;
}
//! @return An object that represents the hash value of the entire sequence
//! @note Time complexity: O(number of bases), which can be regarded as constant time
[[nodiscard]] single_hash whole_string() const {
return single_hash(hashes.back(), size());
}
//! @param starts The index where the substring starts (0-indexed)
//! @param length The length of the substring
//! @return An object that represents the hash value of the substring
//! @note Time complexity: O(number of bases), which can be regarded as constant time
[[nodiscard]] single_hash substring(const int starts, int length = std::numeric_limits<int>::max()) const {
length = std::min(static_cast<int>(std::size(hashes)) - starts - 1, length);
return single_hash(internal::rolling_hash_hpp::substr_hash<Bases...>(hashes, starts, length), length);
}
};
#endif
//! @brief Returns an object that can quickly compute the hash value of a substring as well as the entire string.
//! @tparam Container source container type (deduced from parameter)
//! @param src source (std::string, std::vector, std::array, ...)
//! @return An object of type rolling_hash_t<Container>.
//! @note Time complexity: O(size(src))
template <typename Container>
[[nodiscard]] auto get_rolling_hash(const Container& src) {
return rolling_hash<std::decay_t<decltype(*std::cbegin(std::declval<Container>()))>, 436523069, 681531337, 843203861>(src);
}
//! @brief Returns an object that represents the hash value of the entire string.
//! @tparam Container source container type (deduced from parameter)
//! @param src source (std::string, std::vector, std::array, ...)
//! @return An object of type single_hash_t<Container>.
//! @note Time complexity: O(size(src))
template <typename Container>
[[nodiscard]] auto get_single_hash(const Container& src) {
return get_rolling_hash(src).whole_string();
}
//! @brief return type of get_rolling_hash function
template <typename Container>
using rolling_hash_t = decltype(get_rolling_hash(std::declval<Container>()));
//! @brief return type of get_single_hash function
template <typename Container>
using single_hash_t = decltype(get_single_hash(std::declval<Container>()));
} // namespace lib
#ifdef CP_LIBRARY_ERROR_NOT_DEFINED
# undef CP_LIBRARY_ERROR
# undef CP_LIBRARY_ERROR_NOT_DEFINED
#endif
#ifdef CP_LIBRARY_ASSERT_NOT_DEFINED
# undef CP_LIBRARY_ASSERT
# undef CP_LIBRARY_ASSERT_NOT_DEFINED
#endif
#ifdef CP_LIBRARY_ROLLING_HASH_MAX_LENGTH_NOT_DEFINED
# undef CP_LIBRARY_ROLLING_HASH_MAX_LENGTH
# undef CP_LIBRARY_ROLLING_HASH_MAX_LENGTH_NOT_DEFINED
#endif
#endif // CP_LIBRARY_ROLLING_HASH_HPP
#line 8 "test/string/rolling_hash/2.test.cpp"
int main() {
int N, res = 0;
std::string S;
std::cin >> N >> S;
const auto S_hash = lib::get_rolling_hash(S);
for (int i = 0; i < N; ++i) {
for (int j = i + 1; j < N; ++j) {
int tmp = res;
while (true) {
if (i + tmp >= j || j + tmp >= N)
break;
if (S_hash.substring(i, tmp + 1) != S_hash.substring(j, tmp + 1))
break;
++tmp;
}
res = std::max(res, tmp);
}
}
std::cout << res << '\n';
}