other/dp_cache.hpp

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• Last update: 2025-09-18 22:02:23+07:00
• Include: #include "other/dp_cache.hpp"
• Link: http://xorshift.di.unimi.it/splitmix64.c
• Link: https://www.boost.org/doc/libs/1_55_0/doc/html/hash/combine.html

Code

#pragma once

// clang-format off
namespace hashing {
    using i64 = std::int64_t;
    using u64 = std::uint64_t;
    static const u64 FIXED_RANDOM = std::chrono::steady_clock::now().time_since_epoch().count();

#if USE_AES
    std::mt19937 rd(FIXED_RANDOM);
    const __m128i KEY1{(i64)rd(), (i64)rd()};
    const __m128i KEY2{(i64)rd(), (i64)rd()};
#endif

    template <class T, class D = void>
    struct custom_hash {};

    // https://www.boost.org/doc/libs/1_55_0/doc/html/hash/combine.html
    template <class T>
    inline void hash_combine(u64& seed, const T& v) {
        custom_hash<T> hasher;
        seed ^= hasher(v) + 0x9e3779b97f4a7c15 + (seed << 12) + (seed >> 4);
    };

    // http://xorshift.di.unimi.it/splitmix64.c
    template <class T>
    struct custom_hash<T, typename std::enable_if<std::is_integral<T>::value>::type> {
        u64 operator()(T _x) const {
            u64 x = _x;
#if USE_AES
            // implementation defined till C++17, defined from C++20
            __m128i m{i64(u64(x) * 0xbf58476d1ce4e5b9u64), (i64)FIXED_RANDOM};
            __m128i y = _mm_aesenc_si128(m, KEY1);
            __m128i z = _mm_aesenc_si128(y, KEY2);
            return z[0];
#else
            x += 0x9e3779b97f4a7c15 + FIXED_RANDOM;
            x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
            x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
            return x ^ (x >> 31);
#endif
        }
    };

    template <class T>
    struct custom_hash<T, std::void_t<decltype(std::begin(std::declval<T>()))>> {
        u64 operator()(const T& a) const {
            u64 value = FIXED_RANDOM;
            for (auto& x : a) hash_combine(value, x);
            return value;
        }
    };

    template <class... T>
    struct custom_hash<std::tuple<T...>> {
        u64 operator()(const std::tuple<T...>& a) const {
            u64 value = FIXED_RANDOM;
            std::apply([&value](T const&... args) { (hash_combine(value, args), ...); }, a);
            return value;
        }
    };

    template <class T, class U>
    struct custom_hash<std::pair<T, U>> {
        u64 operator()(const std::pair<T, U>& a) const {
            u64 value = FIXED_RANDOM;
            hash_combine(value, a.first);
            hash_combine(value, a.second);
            return value;
        }
    };

    template<class T>
    struct custom_hash<std::reference_wrapper<T>> {
        u64 operator()(std::reference_wrapper<T> a) const {
            return custom_hash<T>(a.get());
        }
    };
};  // namespace hashing

#include "ext/pb_ds/assoc_container.hpp"

namespace pbds {
    using namespace __gnu_pbds;
#ifdef PB_DS_ASSOC_CNTNR_HPP
    template <class Key, class Value, class Hash>
    using unordered_map = gp_hash_table<Key, Value, Hash, std::equal_to<Key>, direct_mask_range_hashing<>, linear_probe_fn<>,
                                        hash_standard_resize_policy<hash_exponential_size_policy<>, hash_load_check_resize_trigger<>, true>>;
#endif
}  // namespace pbds

template <typename Signature, typename Lambda>
struct Cache;

template <typename ReturnType, typename... Args, typename Lambda>
struct Cache<ReturnType(Args...), Lambda> {
    template <typename... DummyArgs>
    ReturnType operator()(DummyArgs&&... args) {
        auto tied_args = std::tie(args...);
        auto it = memo.find(tied_args);
        if (it == memo.end()) {
            auto&& ans = f(*this, std::forward<DummyArgs>(args)...);
            memo[tied_args] = ans;
            return ans;
        } else {
            return it->second;
        }
    }

    template <class _Lambda>
    Cache(std::tuple<>, _Lambda&& _f) : f(std::forward<_Lambda>(_f)) {}

    Lambda f;
    using TiedArgs = std::tuple<std::decay_t<Args>...>;
    pbds::unordered_map<TiedArgs, ReturnType, hashing::custom_hash<TiedArgs>> memo;
};

template <class Signature, class Lambda>
auto use_cache(Lambda&& f) {
    return Cache<Signature, Lambda>(std::tuple{}, std::forward<Lambda>(f));
}
// clang-format on

Traceback (most recent call last):
  File "/home/runner/.local/lib/python3.12/site-packages/competitive_verifier/oj_resolve/resolver.py", line 181, in resolve
    bundled_code = language.bundle(path, basedir=basedir)
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/runner/.local/lib/python3.12/site-packages/competitive_verifier/oj/verify/languages/cplusplus.py", line 252, in bundle
    bundler.update(path)
  File "/home/runner/.local/lib/python3.12/site-packages/competitive_verifier/oj/verify/languages/cplusplus_bundle.py", line 483, in update
    self._resolve(pathlib.Path(included), included_from=path)
  File "/home/runner/.local/lib/python3.12/site-packages/competitive_verifier/oj/verify/languages/cplusplus_bundle.py", line 291, in _resolve
    raise BundleErrorAt(path, -1, "no such header")
competitive_verifier.oj.verify.languages.cplusplus_bundle.BundleErrorAt: ext/pb_ds/assoc_container.hpp: line -1: no such header

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