結果
問題 | No.2519 Coins in Array |
ユーザー |
|
提出日時 | 2023-10-27 22:12:38 |
言語 | C++17 (gcc 13.3.0 + boost 1.87.0) |
結果 |
AC
|
実行時間 | 81 ms / 2,000 ms |
コード長 | 25,764 bytes |
コンパイル時間 | 3,365 ms |
コンパイル使用メモリ | 215,064 KB |
最終ジャッジ日時 | 2025-02-17 15:09:48 |
ジャッジサーバーID (参考情報) |
judge1 / judge4 |
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ファイルパターン | 結果 |
---|---|
sample | AC * 4 |
other | AC * 37 |
ソースコード
#include <bits/stdc++.h>namespace suisen {template <class T> bool chmin(T& x, const T& y) { return y >= x ? false : (x = y, true); }template <class T> bool chmax(T& x, const T& y) { return y <= x ? false : (x = y, true); }template <class T> constexpr int pow_m1(T n) { return -(n & 1) | 1; }template <class T> constexpr T fld(const T x, const T y) { T q = x / y, r = x % y; return q - ((x ^ y) < 0 and (r != 0)); }template <class T> constexpr T cld(const T x, const T y) { T q = x / y, r = x % y; return q + ((x ^ y) > 0 and (r != 0)); }}namespace suisen::macro {#define IMPL_REPITER(cond) auto& begin() { return *this; } auto end() { return nullptr; } auto& operator*() { return _val; } auto& operator++() {return _val += _step, *this; } bool operator!=(std::nullptr_t) { return cond; }template <class Int, class IntL = Int, class IntStep = Int, std::enable_if_t<(std::is_signed_v<Int> == std::is_signed_v<IntL>), std::nullptr_t> =nullptr> struct rep_impl {Int _val; const Int _end, _step;rep_impl(Int n) : rep_impl(0, n) {}rep_impl(IntL l, Int r, IntStep step = 1) : _val(l), _end(r), _step(step) {}IMPL_REPITER((_val < _end))};template <class Int, class IntL = Int, class IntStep = Int, std::enable_if_t<(std::is_signed_v<Int> == std::is_signed_v<IntL>), std::nullptr_t> =nullptr> struct rrep_impl {Int _val; const Int _end, _step;rrep_impl(Int n) : rrep_impl(0, n) {}rrep_impl(IntL l, Int r) : _val(r - 1), _end(l), _step(-1) {}rrep_impl(IntL l, Int r, IntStep step) : _val(l + fld<Int>(r - l - 1, step) * step), _end(l), _step(-step) {}IMPL_REPITER((_val >= _end))};template <class Int, class IntStep = Int> struct repinf_impl {Int _val; const Int _step;repinf_impl(Int l, IntStep step = 1) : _val(l), _step(step) {}IMPL_REPITER((true))};#undef IMPL_REPITER}#include <iostream>#include <limits>#include <type_traits>namespace suisen {template <typename ...Constraints> using constraints_t = std::enable_if_t<std::conjunction_v<Constraints...>, std::nullptr_t>;template <typename T, typename = std::nullptr_t> struct bitnum { static constexpr int value = 0; };template <typename T> struct bitnum<T, constraints_t<std::is_integral<T>>> { static constexpr int value = std::numeric_limits<std::make_unsigned_t<T>>::digits; };template <typename T> static constexpr int bitnum_v = bitnum<T>::value;template <typename T, size_t n> struct is_nbit { static constexpr bool value = bitnum_v<T> == n; };template <typename T, size_t n> static constexpr bool is_nbit_v = is_nbit<T, n>::value;template <typename T, typename = std::nullptr_t> struct safely_multipliable { using type = T; };template <typename T> struct safely_multipliable<T, constraints_t<std::is_signed<T>, is_nbit<T, 32>>> { using type = long long; };template <typename T> struct safely_multipliable<T, constraints_t<std::is_signed<T>, is_nbit<T, 64>>> { using type = __int128_t; };template <typename T> struct safely_multipliable<T, constraints_t<std::is_unsigned<T>, is_nbit<T, 32>>> { using type = unsigned long long; };template <typename T> struct safely_multipliable<T, constraints_t<std::is_unsigned<T>, is_nbit<T, 64>>> { using type = __uint128_t; };template <typename T> using safely_multipliable_t = typename safely_multipliable<T>::type;template <typename T, typename = void> struct rec_value_type { using type = T; };template <typename T> struct rec_value_type<T, std::void_t<typename T::value_type>> {using type = typename rec_value_type<typename T::value_type>::type;};template <typename T> using rec_value_type_t = typename rec_value_type<T>::type;template <typename T> class is_iterable {template <typename T_> static auto test(T_ e) -> decltype(e.begin(), e.end(), std::true_type{});static std::false_type test(...);public:static constexpr bool value = decltype(test(std::declval<T>()))::value;};template <typename T> static constexpr bool is_iterable_v = is_iterable<T>::value;template <typename T> class is_writable {template <typename T_> static auto test(T_ e) -> decltype(std::declval<std::ostream&>() << e, std::true_type{});static std::false_type test(...);public:static constexpr bool value = decltype(test(std::declval<T>()))::value;};template <typename T> static constexpr bool is_writable_v = is_writable<T>::value;template <typename T> class is_readable {template <typename T_> static auto test(T_ e) -> decltype(std::declval<std::istream&>() >> e, std::true_type{});static std::false_type test(...);public:static constexpr bool value = decltype(test(std::declval<T>()))::value;};template <typename T> static constexpr bool is_readable_v = is_readable<T>::value;} // namespace suisennamespace suisen::io {template <typename IStream, std::enable_if_t<std::conjunction_v<std::is_base_of<std::istream, std::remove_reference_t<IStream>>, std::negation<std::is_const<std::remove_reference_t<IStream>>>>, std::nullptr_t> = nullptr>struct InputStream {private:using istream_type = std::remove_reference_t<IStream>;IStream is;struct { InputStream* is; template <typename T> operator T() { T e; *is >> e; return e; } } _reader{ this };public:template <typename IStream_> InputStream(IStream_ &&is) : is(std::move(is)) {}template <typename IStream_> InputStream(IStream_ &is) : is(is) {}template <typename T> InputStream& operator>>(T& e) {if constexpr (suisen::is_readable_v<T>) is >> e; else _read(e);return *this;}auto read() { return _reader; }template <typename Head, typename... Tail>void read(Head& head, Tail &...tails) { ((*this >> head) >> ... >> tails); }istream_type& get_stream() { return is; }private:static __uint128_t _stou128(const std::string& s) {__uint128_t ret = 0;for (char c : s) if ('0' <= c and c <= '9') ret = 10 * ret + c - '0';return ret;}static __int128_t _stoi128(const std::string& s) { return (s[0] == '-' ? -1 : +1) * _stou128(s); }void _read(__uint128_t& v) { v = _stou128(std::string(_reader)); }void _read(__int128_t& v) { v = _stoi128(std::string(_reader)); }template <typename T, typename U>void _read(std::pair<T, U>& a) { *this >> a.first >> a.second; }template <size_t N = 0, typename ...Args>void _read(std::tuple<Args...>& a) { if constexpr (N < sizeof...(Args)) *this >> std::get<N>(a), _read<N + 1>(a); }template <typename Iterable, std::enable_if_t<suisen::is_iterable_v<Iterable>, std::nullptr_t> = nullptr>void _read(Iterable& a) { for (auto& e : a) *this >> e; }};template <typename IStream>InputStream(IStream &&) -> InputStream<IStream>;template <typename IStream>InputStream(IStream &) -> InputStream<IStream&>;InputStream cin{ std::cin };auto read() { return cin.read(); }template <typename Head, typename... Tail>void read(Head& head, Tail &...tails) { cin.read(head, tails...); }} // namespace suisen::ionamespace suisen { using io::read; } // namespace suisennamespace suisen::io {template <typename OStream, std::enable_if_t<std::conjunction_v<std::is_base_of<std::ostream, std::remove_reference_t<OStream>>, std::negation<std::is_const<std::remove_reference_t<OStream>>>>, std::nullptr_t> = nullptr>struct OutputStream {private:using ostream_type = std::remove_reference_t<OStream>;OStream os;public:template <typename OStream_> OutputStream(OStream_ &&os) : os(std::move(os)) {}template <typename OStream_> OutputStream(OStream_ &os) : os(os) {}template <typename T> OutputStream& operator<<(const T& e) {if constexpr (suisen::is_writable_v<T>) os << e; else _print(e);return *this;}void print() { *this << '\n'; }template <typename Head, typename... Tail>void print(const Head& head, const Tail &...tails) { *this << head, ((*this << ' ' << tails), ...), *this << '\n'; }template <typename Iterable, std::enable_if_t<suisen::is_iterable_v<Iterable>, std::nullptr_t> = nullptr>void print_all(const Iterable& v, std::string sep = " ", std::string end = "\n") {for (auto it = v.begin(); it != v.end();) if (*this << *it; ++it != v.end()) *this << sep;*this << end;}ostream_type& get_stream() { return os; }private:void _print(__uint128_t value) {char buffer[41], *d = std::end(buffer);do *--d = '0' + (value % 10), value /= 10; while (value);os.rdbuf()->sputn(d, std::end(buffer) - d);}void _print(__int128_t value) {if (value < 0) *this << '-';_print(__uint128_t(value < 0 ? -value : value));}template <typename T, typename U>void _print(const std::pair<T, U>& a) { *this << a.first << ' ' << a.second; }template <size_t N = 0, typename ...Args>void _print(const std::tuple<Args...>& a) {if constexpr (N < std::tuple_size_v<std::tuple<Args...>>) {if constexpr (N) *this << ' ';*this << std::get<N>(a), _print<N + 1>(a);}}template <typename Iterable, std::enable_if_t<suisen::is_iterable_v<Iterable>, std::nullptr_t> = nullptr>void _print(const Iterable& a) { print_all(a, " ", ""); }};template <typename OStream_>OutputStream(OStream_ &&) -> OutputStream<OStream_>;template <typename OStream_>OutputStream(OStream_ &) -> OutputStream<OStream_&>;OutputStream cout{ std::cout }, cerr{ std::cerr };template <typename... Args>void print(const Args &... args) { cout.print(args...); }template <typename Iterable, std::enable_if_t<suisen::is_iterable_v<Iterable>, std::nullptr_t> = nullptr>void print_all(const Iterable& v, const std::string& sep = " ", const std::string& end = "\n") { cout.print_all(v, sep, end); }} // namespace suisen::ionamespace suisen { using io::print, io::print_all; } // namespace suisennamespace suisen {template <class T, class ToKey, class CompKey = std::less<>, std::enable_if_t<std::conjunction_v<std::is_invocable<ToKey, T>, std::is_invocable_r<bool, CompKey, std::invoke_result_t<ToKey, T>, std::invoke_result_t<ToKey, T>>>, std::nullptr_t> = nullptr>auto comparator(const ToKey& to_key, const CompKey& comp_key = std::less<>()) {return [=](const T& x, const T& y) { return comp_key(to_key(x), to_key(y)); };}template <class Compare, std::enable_if_t<std::is_invocable_r_v<bool, Compare, int, int>, std::nullptr_t> = nullptr>std::vector<int> sorted_indices(int n, const Compare& compare) {std::vector<int> p(n);return std::iota(p.begin(), p.end(), 0), std::sort(p.begin(), p.end(), compare), p;}template <class ToKey, std::enable_if_t<std::is_invocable_v<ToKey, int>, std::nullptr_t> = nullptr>std::vector<int> sorted_indices(int n, const ToKey& to_key) { return sorted_indices(n, comparator<int>(to_key)); }template <class T, class Comparator>auto priority_queue_with_comparator(const Comparator& comparator) { return std::priority_queue<T, std::vector<T>, Comparator>{ comparator }; }template <class Iterable, std::enable_if_t<suisen::is_iterable_v<Iterable>, std::nullptr_t> = nullptr>void sort_unique_erase(Iterable& a) { std::sort(a.begin(), a.end()), a.erase(std::unique(a.begin(), a.end()), a.end()); }template <size_t D> struct Dim : std::array<int, D> {template <typename ...Ints> Dim(const Ints& ...ns) : std::array<int, D>::array{ static_cast<int>(ns)... } {}};template <typename ...Ints> Dim(const Ints& ...) -> Dim<sizeof...(Ints)>;template <class T, size_t D, size_t I = 0>auto ndvec(const Dim<D> &ns, const T& value = {}) {if constexpr (I + 1 < D) {return std::vector(ns[I], ndvec<T, D, I + 1>(ns, value));} else {return std::vector<T>(ns[I], value);}}}namespace suisen {using int128 = __int128_t;using uint128 = __uint128_t;template <class T> using min_priority_queue = std::priority_queue<T, std::vector<T>, std::greater<T>>;template <class T> using max_priority_queue = std::priority_queue<T, std::vector<T>, std::less<T>>;}namespace suisen { const std::string Yes = "Yes", No = "No", YES = "YES", NO = "NO"; }#ifdef LOCAL# define debug(...) debug_impl(#__VA_ARGS__, __VA_ARGS__)template <class H, class... Ts> void debug_impl(const char* s, const H& h, const Ts&... t) {suisen::io::cerr << "[\033[32mDEBUG\033[m] " << s << ": " << h, ((suisen::io::cerr << ", " << t), ..., (suisen::io::cerr << "\n"));}#else# define debug(...) void(0)#endif#define FOR(e, v) for (auto &&e : v)#define CFOR(e, v) for (const auto &e : v)#define REP(i, ...) CFOR(i, suisen::macro::rep_impl(__VA_ARGS__))#define RREP(i, ...) CFOR(i, suisen::macro::rrep_impl(__VA_ARGS__))#define REPINF(i, ...) CFOR(i, suisen::macro::repinf_impl(__VA_ARGS__))#define LOOP(n) for ([[maybe_unused]] const auto& _ : suisen::macro::rep_impl(n))#define ALL(iterable) std::begin(iterable), std::end(iterable)using namespace suisen;using namespace std;struct io_setup {io_setup(int precision = 20) {std::ios::sync_with_stdio(false), std::cin.tie(nullptr);std::cout << std::fixed << std::setprecision(precision);}} io_setup_{};constexpr int iinf = std::numeric_limits<int>::max() / 2;constexpr long long linf = std::numeric_limits<long long>::max() / 2;#include <cassert>#include <cmath>#include <vector>#include <cstdint>namespace suisen::internal::sieve {constexpr std::uint8_t K = 8;constexpr std::uint8_t PROD = 2 * 3 * 5;constexpr std::uint8_t RM[K] = { 1, 7, 11, 13, 17, 19, 23, 29 };constexpr std::uint8_t DR[K] = { 6, 4, 2, 4, 2, 4, 6, 2 };constexpr std::uint8_t DF[K][K] = {{ 0, 0, 0, 0, 0, 0, 0, 1 }, { 1, 1, 1, 0, 1, 1, 1, 1 },{ 2, 2, 0, 2, 0, 2, 2, 1 }, { 3, 1, 1, 2, 1, 1, 3, 1 },{ 3, 3, 1, 2, 1, 3, 3, 1 }, { 4, 2, 2, 2, 2, 2, 4, 1 },{ 5, 3, 1, 4, 1, 3, 5, 1 }, { 6, 4, 2, 4, 2, 4, 6, 1 },};constexpr std::uint8_t DRP[K] = { 48, 32, 16, 32, 16, 32, 48, 16 };constexpr std::uint8_t DFP[K][K] = {{ 0, 0, 0, 0, 0, 0, 0, 8 }, { 8, 8, 8, 0, 8, 8, 8, 8 },{ 16, 16, 0, 16, 0, 16, 16, 8 }, { 24, 8, 8, 16, 8, 8, 24, 8 },{ 24, 24, 8, 16, 8, 24, 24, 8 }, { 32, 16, 16, 16, 16, 16, 32, 8 },{ 40, 24, 8, 32, 8, 24, 40, 8 }, { 48, 32, 16, 32, 16, 32, 48, 8 },};constexpr std::uint8_t MASK[K][K] = {{ 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80 }, { 0x02, 0x20, 0x10, 0x01, 0x80, 0x08, 0x04, 0x40 },{ 0x04, 0x10, 0x01, 0x40, 0x02, 0x80, 0x08, 0x20 }, { 0x08, 0x01, 0x40, 0x20, 0x04, 0x02, 0x80, 0x10 },{ 0x10, 0x80, 0x02, 0x04, 0x20, 0x40, 0x01, 0x08 }, { 0x20, 0x08, 0x80, 0x02, 0x40, 0x01, 0x10, 0x04 },{ 0x40, 0x04, 0x08, 0x80, 0x01, 0x10, 0x20, 0x02 }, { 0x80, 0x40, 0x20, 0x10, 0x08, 0x04, 0x02, 0x01 },};constexpr std::uint8_t OFFSET[K][K] = {{ 0, 1, 2, 3, 4, 5, 6, 7, },{ 1, 5, 4, 0, 7, 3, 2, 6, },{ 2, 4, 0, 6, 1, 7, 3, 5, },{ 3, 0, 6, 5, 2, 1, 7, 4, },{ 4, 7, 1, 2, 5, 6, 0, 3, },{ 5, 3, 7, 1, 6, 0, 4, 2, },{ 6, 2, 3, 7, 0, 4, 5, 1, },{ 7, 6, 5, 4, 3, 2, 1, 0, },};constexpr std::uint8_t mask_to_index(const std::uint8_t bits) {switch (bits) {case 1 << 0: return 0;case 1 << 1: return 1;case 1 << 2: return 2;case 1 << 3: return 3;case 1 << 4: return 4;case 1 << 5: return 5;case 1 << 6: return 6;case 1 << 7: return 7;default: assert(false);}}} // namespace suisen::internal::sievenamespace suisen {template <unsigned int N>class SimpleSieve {private:static constexpr unsigned int siz = N / internal::sieve::PROD + 1;static std::uint8_t flag[siz];public:SimpleSieve() {using namespace internal::sieve;flag[0] |= 1;unsigned int k_max = (unsigned int) std::sqrt(N + 2) / PROD;for (unsigned int kp = 0; kp <= k_max; ++kp) {for (std::uint8_t bits = ~flag[kp]; bits; bits &= bits - 1) {const std::uint8_t mp = mask_to_index(bits & -bits), m = RM[mp];unsigned int kr = kp * (PROD * kp + 2 * m) + m * m / PROD;for (std::uint8_t mq = mp; kr < siz; kr += kp * DR[mq] + DF[mp][mq], ++mq &= 7) {flag[kr] |= MASK[mp][mq];}}}}std::vector<int> prime_list(unsigned int max_val = N) const {using namespace internal::sieve;std::vector<int> res { 2, 3, 5 };res.reserve(max_val / 25);for (unsigned int i = 0, offset = 0; i < siz and offset < max_val; ++i, offset += PROD) {for (uint8_t f = ~flag[i]; f;) {uint8_t g = f & -f;res.push_back(offset + RM[mask_to_index(g)]);f ^= g;}}while (res.size() and (unsigned int) res.back() > max_val) res.pop_back();return res;}bool is_prime(const unsigned int p) const {using namespace internal::sieve;switch (p) {case 2: case 3: case 5: return true;default:switch (p % PROD) {case RM[0]: return ((flag[p / PROD] >> 0) & 1) == 0;case RM[1]: return ((flag[p / PROD] >> 1) & 1) == 0;case RM[2]: return ((flag[p / PROD] >> 2) & 1) == 0;case RM[3]: return ((flag[p / PROD] >> 3) & 1) == 0;case RM[4]: return ((flag[p / PROD] >> 4) & 1) == 0;case RM[5]: return ((flag[p / PROD] >> 5) & 1) == 0;case RM[6]: return ((flag[p / PROD] >> 6) & 1) == 0;case RM[7]: return ((flag[p / PROD] >> 7) & 1) == 0;default: return false;}}}};template <unsigned int N>std::uint8_t SimpleSieve<N>::flag[SimpleSieve<N>::siz];template <unsigned int N>class Sieve {private:static constexpr unsigned int base_max = (N + 1) * internal::sieve::K / internal::sieve::PROD;static unsigned int pf[base_max + internal::sieve::K];public:Sieve() {using namespace internal::sieve;pf[0] = 1;unsigned int k_max = ((unsigned int) std::sqrt(N + 1) - 1) / PROD;for (unsigned int kp = 0; kp <= k_max; ++kp) {const int base_i = kp * K, base_act_i = kp * PROD;for (int mp = 0; mp < K; ++mp) {const int m = RM[mp], i = base_i + mp;if (pf[i] == 0) {unsigned int act_i = base_act_i + m;unsigned int base_k = (kp * (PROD * kp + 2 * m) + m * m / PROD) * K;for (std::uint8_t mq = mp; base_k <= base_max; base_k += kp * DRP[mq] + DFP[mp][mq], ++mq &= 7) {pf[base_k + OFFSET[mp][mq]] = act_i;}}}}}bool is_prime(const unsigned int p) const {using namespace internal::sieve;switch (p) {case 2: case 3: case 5: return true;default:switch (p % PROD) {case RM[0]: return pf[p / PROD * K + 0] == 0;case RM[1]: return pf[p / PROD * K + 1] == 0;case RM[2]: return pf[p / PROD * K + 2] == 0;case RM[3]: return pf[p / PROD * K + 3] == 0;case RM[4]: return pf[p / PROD * K + 4] == 0;case RM[5]: return pf[p / PROD * K + 5] == 0;case RM[6]: return pf[p / PROD * K + 6] == 0;case RM[7]: return pf[p / PROD * K + 7] == 0;default: return false;}}}int prime_factor(const unsigned int p) const {using namespace internal::sieve;switch (p % PROD) {case 0: case 2: case 4: case 6: case 8:case 10: case 12: case 14: case 16: case 18:case 20: case 22: case 24: case 26: case 28: return 2;case 3: case 9: case 15: case 21: case 27: return 3;case 5: case 25: return 5;case RM[0]: return pf[p / PROD * K + 0] ? pf[p / PROD * K + 0] : p;case RM[1]: return pf[p / PROD * K + 1] ? pf[p / PROD * K + 1] : p;case RM[2]: return pf[p / PROD * K + 2] ? pf[p / PROD * K + 2] : p;case RM[3]: return pf[p / PROD * K + 3] ? pf[p / PROD * K + 3] : p;case RM[4]: return pf[p / PROD * K + 4] ? pf[p / PROD * K + 4] : p;case RM[5]: return pf[p / PROD * K + 5] ? pf[p / PROD * K + 5] : p;case RM[6]: return pf[p / PROD * K + 6] ? pf[p / PROD * K + 6] : p;case RM[7]: return pf[p / PROD * K + 7] ? pf[p / PROD * K + 7] : p;default: assert(false);}}/*** Returns a vector of `{ prime, index }`.*/std::vector<std::pair<int, int>> factorize(unsigned int n) const {assert(0 < n and n <= N);std::vector<std::pair<int, int>> prime_powers;while (n > 1) {int p = prime_factor(n), c = 0;do { n /= p, ++c; } while (n % p == 0);prime_powers.emplace_back(p, c);}return prime_powers;}/*** Returns the divisors of `n`.* It is NOT guaranteed that the returned vector is sorted.*/std::vector<int> divisors(unsigned int n) const {assert(0 < n and n <= N);std::vector<int> divs { 1 };for (auto [prime, index] : factorize(n)) {int sz = divs.size();for (int i = 0; i < sz; ++i) {int d = divs[i];for (int j = 0; j < index; ++j) {divs.push_back(d *= prime);}}}return divs;}};template <unsigned int N>unsigned int Sieve<N>::pf[Sieve<N>::base_max + internal::sieve::K];} // namespace suisenSieve<200010> sieve;long long f(long long x, long long y) {if (gcd(x, y) != 1) return 0;return (x - 1) * (y - 1);}void solve() {int n;read(n);vector<long long> a(n);read(a);vector<vector<int>> mul(200010);REP(i, n) {if (a[i] == 0) {print(0);if (i == 0) {print(i + 1, 2);} else {print(i + 1, 1);}int cur = n - 2;LOOP(n - 2) {print(1, cur + 1);--cur;}return;}for (auto [p, q] : sieve.factorize(a[i])) {mul[p].push_back(i);}}REP(p, 200010) {if (mul[p].size() >= 2) {int a = mul[p][0], b = mul[p][1];print(0);print(a + 1, b + 1);int cur = n - 2;LOOP(n - 2) {print(1, cur + 1);--cur;}return;}}if (n == 2) {print(f(a[0], a[1]));print(1, 2);return;}int evn = -1;REP(i, n) {if (a[i] % 2 == 0) evn = i;}if (evn != -1) {int i = 0, j = 1;if (i == evn) i = 2;if (j == evn) j = 2;print(0);evn -= (i < evn) + (j < evn);print(i + 1, j + 1);print(evn + 1, n - 1);int cur = n - 3;LOOP(n - 3) {print(1, cur + 1);--cur;}return;}if (n == 3) {long long m = linf;vector<pair<int, int>> ans;auto dfs = [&](auto dfs, vector<long long> a, vector<pair<int, int>> op) {const int n = a.size();if (n == 1) {if (chmin(m, a[0])) {ans = op;}return;}REP(i, n) REP(j, i) {vector<long long> na;REP(k, n) if (k != i and k != j) na.push_back(a[k]);na.push_back(f(a[i], a[j]));op.emplace_back(i, j);dfs(dfs, na, op);op.pop_back();}};dfs(dfs, a, {});print(m);for (auto [i, j] : ans) print(i + 1, j + 1);return;}print(0);print(1, 2);print(1, 2);print(n - 3, n - 2);int cur = n - 4;LOOP(n - 4) {print(1, cur + 1);--cur;}}int main() {int test_case_num = 1;// read(test_case_num);LOOP(test_case_num) solve();return 0;}