QOJ.ac

QOJ

IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#239730#7688. Alea Iacta Estucup-team197#Compile Error//C++1418.7kb2023-11-04 22:48:152023-11-04 22:48:15

Judging History

你现在查看的是最新测评结果

  • [2023-11-04 22:48:15]
  • 评测
  • [2023-11-04 22:48:15]
  • 提交

answer

#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi2")
// <io.hpp>
#include <array>
#include <limits>
// <local_assertion.hpp>
#include <iostream>
#ifdef ENABLE_DEBUG
#define LOCAL_ASSERT(condition, message)                                       \
    do {                                                                       \
        if (!(condition)) {                                                    \
            std::cerr << "Assertion (" << #condition << ") failed\non line "   \
                      << __LINE__ << " in " << __FILE__ << '#' << __FUNCTION__ \
                      << "()\n";                                               \
            std::cerr << message << '\n';                                      \
            abort();                                                           \
        }                                                                      \
    } while (0)
#else
#define LOCAL_ASSERT(...) \
    do {                  \
    } while (0)
#endif
#define LOCAL_ASSERT_IN_RANGE(variable, low, high)                       \
    LOCAL_ASSERT(low <= variable && variable <= high,                    \
                 #variable << '=' << variable << " is out of the range " \
                           << '[' << low << ", " << high << ']')
// </local_assertion.hpp>
#include <variant>
// <io/BufferedInput.hpp>
#ifdef _WIN32
#include <windows.h>
#else
#include <fcntl.h>
#include <unistd.h>
#endif
#include <cstdio>
#include <cstring>
#include <memory>
// <ints.hpp>
#include <cstddef>
#include <cstdint>
using i8 = std::int8_t;
using u8 = std::uint8_t;
using i16 = std::int16_t;
using u16 = std::uint16_t;
using i32 = std::int32_t;
using u32 = std::uint32_t;
using i64 = std::int64_t;
using u64 = std::uint64_t;
#ifdef __SIZEOF_INT128__
using i128 = __int128_t;
using u128 = __uint128_t;
#endif
using isize = std::ptrdiff_t;
using usize = std::size_t;
// </ints.hpp>
template <usize buffer_size>
struct BufferedInput {
    std::unique_ptr<char[]> buffer;
    const char *cursor;
    usize len;
    BufferedInput() : buffer(std::make_unique<char[]>(buffer_size)), cursor(buffer.get()), len(0) {
#ifdef _WIN32
        HANDLE stdin_handle = GetStdHandle(STD_INPUT_HANDLE);
        DWORD mode;
        if (GetConsoleMode(stdin_handle, &mode)) {
            if (!SetConsoleMode(stdin_handle, mode & ~ENABLE_LINE_INPUT & ~ENABLE_ECHO_INPUT)) {
                std::cerr << "failed setting console mode: " << GetLastError() << '\n';
            }
        } else {
            std::cerr << "failed getting current console mode: " << GetLastError() << '\n';
        }
#else
        int flags = fcntl(STDIN_FILENO, F_GETFL, 0);
        fcntl(STDIN_FILENO, F_SETFL, flags | O_NONBLOCK);
#endif
        refill();
    }
    BufferedInput(const BufferedInput &) = delete;
    BufferedInput(BufferedInput &&other) : buffer(std::move(other.buffer)), cursor(other.cursor), len(other.len) {
        other.cursor = nullptr;
        other.len = 0;
    }
    auto operator=(const BufferedInput &) -> BufferedInput & = delete;
    auto operator=(BufferedInput &&other) -> BufferedInput & = delete;
    ~BufferedInput() {
        if (buffer) {
#ifdef ENABLE_DEBUG
            refill();
#endif
            LOCAL_ASSERT(cursor == buffer.get() + len || (cursor + 1 == buffer.get() + len && *cursor == '\n'),
                         "Input buffer not fully consumed");
        }
    }
    enum class RefillState { OK, WAITING, AT_EOF };
    RefillState refill() {
        std::memmove(buffer.get(), cursor, buffer.get() + len - cursor);
        len -= cursor - buffer.get();
        cursor = buffer.get();
        std::size_t amt = std::fread(buffer.get() + len, 1, buffer_size - len, stdin);
        if (amt) {
            len += amt;
            return RefillState::OK;
        } else if (std::feof(stdin)) {
            return RefillState::AT_EOF;
        } else {
            return RefillState::WAITING;
        }
    }
    auto get_buffer(usize n) -> std::pair<const char *, usize> {
        if (cursor + n > buffer.get() + len) {
            RefillState state;
            do {
                state = refill();
            } while (cursor == buffer.get() + len && state == RefillState::WAITING);
            LOCAL_ASSERT(cursor != buffer.get() + len, "requested input beyond EOF");
        }
        auto remain_len = buffer.get() + len - cursor;
        return {cursor, remain_len};
    }
    auto consume(usize n) -> void {
        LOCAL_ASSERT(cursor + n <= buffer.get() + len, "Input buffer overflow");
        cursor += n;
    }
};
// </io/BufferedInput.hpp>
// <io/BufferedOutput.hpp>
#include <cstdio>
#include <cstring>
template <usize buffer_size>
struct BufferedOutput {
    char buffer[buffer_size];
    char *cursor;
    BufferedOutput() : cursor(buffer) {}
    ~BufferedOutput() { flush(); }
    BufferedOutput(const BufferedOutput &) = delete;
    BufferedOutput(BufferedOutput &&other) {
        setvbuf(stdout, NULL, _IONBF, 0);
        std::memcpy(buffer, other.buffer, other.cursor - other.buffer);
        cursor = buffer + (other.cursor - other.buffer);
    }
    BufferedOutput &operator=(const BufferedOutput &) = delete;
    BufferedOutput &operator=(BufferedOutput &&other) = delete;
    void flush() {
        LOCAL_ASSERT_IN_RANGE(cursor - buffer, 0, buffer_size);
        std::fwrite(buffer, 1, cursor - buffer, stdout);
        cursor = buffer;
    }
    void write(const char *s, usize len) {
        if (cursor + len > buffer + buffer_size) {
            flush();
            if (len > buffer_size) {
                std::fwrite(s, 1, len, stdout);
                return;
            }
        }
        std::memcpy(cursor, s, len);
        cursor += len;
    }
    void write(char c) {
        if (cursor == buffer + buffer_size) flush();
        *cursor++ = c;
    }
};
// </io/BufferedOutput.hpp>
// <io/MemoryMappedInput.hpp>
#include <cerrno>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <optional>
#include <utility>
#ifdef _WIN32
#include <Windows.h>
#else
#include <sys/mman.h>
#include <sys/stat.h>
#include <unistd.h>
#endif
struct MemoryMappedInput {
    const char *stdin_buffer;
    const char *cursor;
    usize len;
#ifdef _WIN32
    HANDLE stdin_mapping;
#endif
    static auto create() -> std::optional<MemoryMappedInput> {
        auto fail = [](auto... args) -> std::optional<MemoryMappedInput> {
            std::fprintf(stderr, args...);
            std::fflush(stderr);
            return std::nullopt;
        };
#ifdef _WIN32
        HANDLE stdin_handle = GetStdHandle(STD_INPUT_HANDLE);
        if (stdin_handle == INVALID_HANDLE_VALUE) {
            return fail("Error: GetStdHandle failed: %d\n", GetLastError());
        }
        DWORD dwFileSizeHigh = 0;
        DWORD dwFileSizeLow = GetFileSize(stdin_handle, &dwFileSizeHigh);
        if (dwFileSizeLow == INVALID_FILE_SIZE) {
            return fail("Error: GetFileSize failed: %d\n", GetLastError());
        }
        usize len = usize(dwFileSizeLow + (u64(dwFileSizeHigh) << 32));
        HANDLE stdin_mapping =
            CreateFileMapping(stdin_handle, nullptr, PAGE_READONLY,
                              dwFileSizeHigh, dwFileSizeLow, nullptr);
        if (stdin_mapping == nullptr) {
            return fail("Error: CreateFileMapping failed: %d\n",
                        GetLastError());
        }
        const char *stdin_buffer = static_cast<const char *>(
            MapViewOfFile(stdin_mapping, FILE_MAP_READ, 0, 0, len));
        if (stdin_buffer == nullptr) {
            auto err = GetLastError();
            CloseHandle(stdin_mapping);
            return fail("Error: MapViewOfFile failed: %d\n", err);
        }
#else
        u32 stat_err;
        struct stat stat;
        stat_err = fstat(STDIN_FILENO, &stat);
        if (stat_err != 0) {
            return fail("Error: fstat failed: %d\n", stat_err);
        }
        usize len = usize(stat.st_size);
        const char *stdin_buffer = static_cast<const char *>(
            mmap(nullptr, len, PROT_READ, MAP_PRIVATE, 0, 0));
        if (stdin_buffer == MAP_FAILED) {
            return fail("Error: mmap failed: %d\n", errno);
        }
#endif
        return MemoryMappedInput{stdin_buffer, len};
    }
    MemoryMappedInput(const char *stdin_buffer, usize len)
        : stdin_buffer(stdin_buffer), cursor(stdin_buffer), len(len) {}
    MemoryMappedInput(const MemoryMappedInput &) = delete;
    MemoryMappedInput(MemoryMappedInput &&other)
        : stdin_buffer(other.stdin_buffer),
          cursor(other.cursor),
          len(other.len) {
        other.stdin_buffer = nullptr;
        other.cursor = nullptr;
        other.len = 0;
#ifdef _WIN32
        other.stdin_mapping = nullptr;
#endif
    }
    auto operator=(const MemoryMappedInput &) -> MemoryMappedInput & = delete;
    auto operator=(MemoryMappedInput &&other) -> MemoryMappedInput & = delete;
    ~MemoryMappedInput() {
        if (stdin_buffer != nullptr) {
            /*
            LOCAL_ASSERT(cursor == stdin_buffer + len ||
                             (cursor + 1 == stdin_buffer + len && *cursor ==
            '\n'), "Input not fully consumed");
            */
#ifdef _WIN32
            UnmapViewOfFile(stdin_buffer);
            CloseHandle(stdin_mapping);
#else
            munmap(const_cast<char *>(stdin_buffer), len);
#endif
        }
    }
    auto get_buffer([[maybe_unused]] usize n) const
        -> std::pair<const char *, usize> {
        auto remain_len = static_cast<usize>(stdin_buffer + len - cursor);
        LOCAL_ASSERT(remain_len != 0, "Input buffer empty");
        return {cursor, remain_len};
    }
    auto consume(usize n) -> void {
        LOCAL_ASSERT(cursor + n <= stdin_buffer + len, "Input buffer overflow");
        cursor += n;
    }
};
// </io/MemoryMappedInput.hpp>
template <class T>
static constexpr auto base10_max_len() {
    static_assert(std::is_integral_v<T>);
    return usize(sizeof(T) * 8 * .302 + 2);
}
template <class Reader, class T, class = void>
struct InputImpl {};
template <class Writer, class T, class = void>
struct OutputImpl {};
struct IO {
    static constexpr usize buffer_size = 1 << 17;
    using Input = std::variant<MemoryMappedInput, BufferedInput<buffer_size>>;
    using Output = std::variant<BufferedOutput<buffer_size>>;
    Input input;
    Output output;
    static auto init_input() -> Input {
        auto out = MemoryMappedInput::create();
        if (out) return std::move(*out);
        return BufferedInput<buffer_size>();
    }
    static auto init_output() -> Output { return BufferedOutput<buffer_size>(); }
    IO() : input(init_input()), output(init_output()) {}
    template <class T>
    auto operator>>(T &rhs) -> IO & {
        std::visit([&](auto &input) { InputImpl<decltype(input), T>{}.read(input, rhs); }, input);
        return *this;
    }
    template <class T>
    auto operator<<(const T &rhs) -> IO & {
        std::visit([&](auto &output) { OutputImpl<decltype(output), T>{}.write(output, rhs); }, output);
        return *this;
    }
    template <class InputType, class OutputType>
    struct TypedIO {
        InputType &input;
        OutputType &output;
        TypedIO(InputType &input_, OutputType &output_) : input(input_), output(output_) {}
        template <class T>
        auto operator>>(T &rhs) -> TypedIO & {
            InputImpl<decltype(input), T>{}.read(input, rhs);
            return *this;
        }
        template <class T>
        auto operator<<(const T &rhs) -> TypedIO & {
            OutputImpl<decltype(output), T>{}.write(output, rhs);
            return *this;
        }
        auto flush() { return output.flush(); }
    };
    template <class F>
    void run(F f) {
        std::visit([&](auto &input, auto &output) { f(TypedIO(input, output)); }, input, output);
    }
};
template <class Reader>
auto skip_whitespace(Reader &reader, usize n) -> std::tuple<const char *, usize, usize> {
    auto [buf, buf_len] = reader.get_buffer(n);
    usize buf_idx = 0;
    while (1) {
        while (buf_idx != buf_len) {
            if (buf[buf_idx] > ' ') return {buf, buf_len, buf_idx};
            ++buf_idx;
        }
        reader.consume(buf_idx);
        buf_idx = 0;
        std::tie(buf, buf_len) = reader.get_buffer(n);
    }
}
template <class Reader, class T>
struct InputImpl<Reader, T, std::enable_if_t<std::is_integral_v<T>>> {
    void read(Reader &reader, T &rhs) {
        constexpr auto max_len = base10_max_len<T>();
        auto [buf, buf_len, buf_idx] = skip_whitespace(reader, max_len);
        auto inner = [&]() {
            rhs = 0;
            while (1) {
                while (buf_idx != buf_len) {
                    if (buf[buf_idx] <= ' ') {
                        reader.consume(buf_idx);
                        return;
                    }
                    rhs = rhs * 10 + buf[buf_idx] - '0';
                    ++buf_idx;
                }
                reader.consume(buf_idx);
                buf_idx = 0;
                std::tie(buf, buf_len) = reader.get_buffer(max_len);
            }
        };
        if constexpr (std::is_signed_v<T>) {
            if (buf[buf_idx] == '-') {
                ++buf_idx;
                inner();
                rhs = -rhs;
            } else {
                inner();
            }
        } else {
            inner();
        }
    }
};
template <class Reader>
struct InputImpl<Reader, char> {
    void read(Reader &reader, char &rhs) {
        auto [buf, buf_len, buf_idx] = skip_whitespace(reader, 1);
        rhs = buf[buf_idx++];
        reader.consume(buf_idx);
    }
};
template <class Reader>
struct InputImpl<Reader, std::string> {
    void read(Reader &reader, std::string &rhs) {
        rhs.clear();
        auto [buf, buf_len, buf_idx] = skip_whitespace(reader, 1);
        while (1) {
            u32 p = buf_idx;
            while (p != buf_len) {
                if (buf[p] <= ' ') break;
                ++p;
            }
            rhs += std::string_view(buf + buf_idx, buf + p);
            reader.consume(p);
            if (p != buf_len) return;
            buf_idx = 0;
            std::tie(buf, buf_len) = reader.get_buffer(1);
        }
    }
};
static constexpr auto digits_10k = []() {
    auto res = std::array<char, 10'000 * 4>{};
    for (u32 i = 0; i != 10'000; ++i) {
        u32 p = 4 * (i + 1);
        u32 rem = i;
        for (int rep = 0; rep != 4; ++rep) {
            res[--p] = char('0' + rem % 10);
            rem /= 10;
        }
    }
    return res;
}();
template <class Writer, class T>
struct OutputImpl<Writer, T, std::enable_if_t<std::is_integral_v<T>>> {
    void write(Writer &writer, T rhs) {
        if (rhs == 0) {
            writer.write('0');
            return;
        }
        constexpr auto max_len = base10_max_len<T>();
        char buf[max_len];
        usize buf_idx = max_len;
        if constexpr (std::is_signed_v<T>) {
            if (rhs < 0) {
                writer.write('-');
                if (rhs == std::numeric_limits<T>::min()) {
                    buf[--buf_idx] = char('0' - std::numeric_limits<T>::min() % 10);
                    rhs = std::numeric_limits<T>::min() / 10;
                }
                rhs = -rhs;
            }
        }
        while (rhs >= 1000) {
            buf_idx -= 4;
            std::memcpy(buf + buf_idx, digits_10k.data() + rhs % 10'000 * 4, 4);
            rhs /= 10'000;
        }
        if (rhs <= 9) {
            if (rhs != 0) {
                buf[--buf_idx] = char('0' + rhs);
            }
        } else if (rhs <= 99) {
            u32 hi = (u32(rhs) * 205) >> 11;
            u32 lo = u32(rhs) - 10 * hi;
            buf[--buf_idx] = char('0' + lo);
            buf[--buf_idx] = char('0' + hi);
        } else {
            buf_idx -= 3;
            std::memcpy(buf + buf_idx, digits_10k.data() + rhs * 4 + 1, 3);
        }
        writer.write(buf + buf_idx, max_len - buf_idx);
    }
};
template <class Writer>
struct OutputImpl<Writer, char> {
    void write(Writer &writer, char rhs) { writer.write(rhs); }
};
template <class Writer, usize n>
struct OutputImpl<Writer, char[n]> {
    void write(Writer &writer, const char *rhs) { writer.write(rhs, std::strlen(rhs)); }
};
// </io.hpp>





#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define fi first
#define se second
const int N=3e6+5;
const int iu=1e6;
vector<int>pf[N];
ll n,m;
int sz=0;
ll v[N];
void gen(vector<pair<ll,ll> >&g,int id,ll cur){
	if(id==g.size()){
		v[++sz]=cur;
		return;
	}
	for(int i=0; i<g[id].fi ;i++){
		ll dx=i*g[id].se;
		gen(g,id+1,cur+dx);
	}
}
ll gcd(ll x,ll y){
	if(y==0) return x;
	return gcd(y,x%y);
}
void solve(){
	io >> n >> m;
	if(n>m) swap(n,m);
	if(n==1 && pf[m].size()<=1){
		io << "0\n0\n";
		return;
	}
	ll xs=n;
	for(ll s=n+1; s<=m ;s++){
		if(s*s>n*m) break;
		if(n*m%s==0) xs=s;
	}
	ll g=gcd(n,m);
	if(n==m && pf[n].size()==1) g=1;
	vector<pair<ll,ll> >gl,gr;
	if(xs==n && g!=1){
		ll p=pf[g][0];
		for(int i=0; i<pf[n].size() ;i++){
			if(pf[n][i]==p){
				swap(pf[n][0],pf[n][i]);
				break;
			}
		}
		{
			ll step=1;
			for(auto c:pf[n]){
				gl.push_back({c,step});
				step*=c;
			}
		}
		for(int i=0; i<pf[m].size() ;i++){
			if(pf[m][i]==p){
				swap(pf[m][0],pf[m][i]);
				break;
			}
		}
		swap(pf[m][0],pf[m].back());
		{
			ll step=1;
			for(auto c:pf[m]){
				gr.push_back({c,step});
				step*=c;
			}
		}
		swap(gl[0],gr.back());
	}
	else{
		if(xs==n){
			xs--;
			while(n*m%xs!=0) --xs;
		}
		vector<pair<ll,ll> >gn;
		{
			ll step=1;
			for(auto c:pf[n]){
				gn.push_back({c,step});
				step*=c;
			}
		}
		{
			ll step=1;
			for(auto c:pf[m]){
				gn.push_back({c,step});
				step*=c;
			}
		}
		for(auto c:gn){
			if(xs%c.fi==0){
				xs/=c.fi;
				gl.push_back(c);
			}
			else gr.push_back(c);
		}
	}
	
	sz=0;
	gen(gl,0,0);
	io << sz << ' ';
	for(int i=1; i<=sz ;i++) io << v[i]+1 << ' ';
	io << '\n';
	sz=0;
	gen(gr,0,0);
	io << sz << ' ';
	for(int i=1; i<=sz ;i++) io << v[i]+1 << ' ';
	io << '\n';
}

auto io_main = [](auto &&io) -> void {
	
	for(int i=2; i<=iu ;i++){
		if(!pf[i].empty()) continue;
		for(int j=i; j<=iu ;j+=i){
			int z=j;
			while(z%i==0){
				z/=i;
				pf[j].push_back(i);
			}
		}
	}
	int t;io >> t;
	while(t--) solve();
    /*u32 n;
    io >> n;
    i64 s = 0;
    while (n--) {
        i64 x;
        io >> x;
        s ^= x;
        io << s << ' ';
    }
    io << '\n';*/
};

auto main() -> int {
    auto io = IO();
    io.run(io_main);
}

Details

answer.code:188:34: error: ‘optional’ in namespace ‘std’ does not name a template type
  188 |     static auto create() -> std::optional<MemoryMappedInput> {
      |                                  ^~~~~~~~
answer.code:188:29: note: ‘std::optional’ is only available from C++17 onwards
  188 |     static auto create() -> std::optional<MemoryMappedInput> {
      |                             ^~~
answer.code:188:34: error: expected ‘;’ at end of member declaration
  188 |     static auto create() -> std::optional<MemoryMappedInput> {
      |                                  ^~~~~~~~
      |                                          ;
answer.code:188:42: error: expected unqualified-id before ‘<’ token
  188 |     static auto create() -> std::optional<MemoryMappedInput> {
      |                                          ^
answer.code: In function ‘constexpr auto base10_max_len()’:
answer.code:280:24: error: ‘is_integral_v’ is not a member of ‘std’; did you mean ‘is_integral’?
  280 |     static_assert(std::is_integral_v<T>);
      |                        ^~~~~~~~~~~~~
      |                        is_integral
answer.code:280:39: error: expected primary-expression before ‘>’ token
  280 |     static_assert(std::is_integral_v<T>);
      |                                       ^
answer.code:280:40: error: expected primary-expression before ‘)’ token
  280 |     static_assert(std::is_integral_v<T>);
      |                                        ^
answer.code: At global scope:
answer.code:289:24: error: ‘variant’ in namespace ‘std’ does not name a template type
  289 |     using Input = std::variant<MemoryMappedInput, BufferedInput<buffer_size>>;
      |                        ^~~~~~~
answer.code:289:19: note: ‘std::variant’ is only available from C++17 onwards
  289 |     using Input = std::variant<MemoryMappedInput, BufferedInput<buffer_size>>;
      |                   ^~~
answer.code:290:25: error: ‘variant’ in namespace ‘std’ does not name a template type
  290 |     using Output = std::variant<BufferedOutput<buffer_size>>;
      |                         ^~~~~~~
answer.code:290:20: note: ‘std::variant’ is only available from C++17 onwards
  290 |     using Output = std::variant<BufferedOutput<buffer_size>>;
      |                    ^~~
answer.code:291:5: error: ‘Input’ does not name a type
  291 |     Input input;
      |     ^~~~~
answer.code:292:5: error: ‘Output’ does not name a type
  292 |     Output output;
      |     ^~~~~~
answer.code:293:33: error: ‘Input’ does not name a type
  293 |     static auto init_input() -> Input {
      |                                 ^~~~~
answer.code:298:34: error: ‘Output’ does not name a type
  298 |     static auto init_output() -> Output { return BufferedOutput<buffer_size>(); }
      |                                  ^~~~~~
answer.code: In constructor ‘IO::IO()’:
answer.code:299:12: error: class ‘IO’ does not have any field named ‘input’
  299 |     IO() : input(init_input()), output(init_output()) {}
      |            ^~~~~
answer.code:299:18: error: ‘init_input’ was not declared in this scope
  299 |     IO() : input(init_input()), output(init_output()) {}
      |                  ^~~~~~~~~~
answer.code:299:33: error: class ‘IO’ does not have any field named ‘output’
  299 |     IO() : input(init_input()), output(init_output()) {}
      |                                 ^~~~~~
answer.code:299:40: error: ‘init_output’ was not declared in this scope
  299 |     IO() : input(init_input()), output(init_output()) {}
      |                                        ^~~~~~~~~~~
answer.code: In member function ‘IO& IO::operator>>(T&)’:
answer.code:302:14: error: ‘visit’ is not a member of ‘std’
  302 |         std::visit([&](auto &input) { InputImpl<decltype(input), T>{}.read(input, rhs); }, input);
      |              ^~~~~
answer.code:302:14: note: ‘std::visit’ is only available from C++17 onwards
answer.code:302:92: error: ‘input’ was not declared in this scope; did you mean ‘int’?
  302 |         std::visit([&](auto &input) { InputImpl<decltype(input), T>{}.read(input, rhs); }, input);
      |                                                                                            ^~~~~
      |                                                                                            int
answer.code: In member function ‘IO& IO::operator<<(const T&)’:
answer.code:307:14: error: ‘visit’ is not a member of ‘std’
  307 |         std::visit([&](auto &output) { OutputImpl<decltype(output), T>{}.write(output, rhs); }, output);
      |              ^~~~~
answer.code:307:14: note: ‘std::visit’ is only available from C++17 onwards
answer.code:307:97: error: ‘output’ was not declared in this scope
  307 |         std::visit([&](auto &output) { OutputImpl<decltype(output), T>{}.write(output, rhs); }, output);
      |                                                                                                 ^~~~~~
answer.code: In member function ‘void IO::run(F)’:
ans...