結果
| 問題 |
No.2337 Equidistant
|
| コンテスト | |
| ユーザー |
 shiomusubi496
|
| 提出日時 | 2023-06-02 22:32:30 |
| 言語 | C++17 (gcc 13.3.0 + boost 1.87.0) |
| 結果 |
AC
|
| 実行時間 | 1,009 ms / 4,000 ms |
| コード長 | 49,272 bytes |
| コンパイル時間 | 2,928 ms |
| コンパイル使用メモリ | 226,560 KB |
| 最終ジャッジ日時 | 2025-02-13 19:23:00 |
|
ジャッジサーバーID （参考情報） |
judge3 / judge1 |
（要ログイン）
| ファイルパターン | 結果 |
|---|---|
| sample | AC * 1 |
| other | AC * 28 |
ソースコード
#line 2 "library/other/template.hpp"
#include <bits/stdc++.h>
#line 2 "library/template/macros.hpp"
#line 4 "library/template/macros.hpp"
#ifndef __COUNTER__
#define __COUNTER__ __LINE__
#endif
#define REP_SELECTER(a, b, c, d, e, ...) e
#define REP1_0(b, c) REP1_1(b, c)
#define REP1_1(b, c) \
for (ll REP_COUNTER_##c = 0; REP_COUNTER_##c < (ll)(b); ++REP_COUNTER_##c)
#define REP1(b) REP1_0(b, __COUNTER__)
#define REP2(i, b) for (ll i = 0; i < (ll)(b); ++i)
#define REP3(i, a, b) for (ll i = (ll)(a); i < (ll)(b); ++i)
#define REP4(i, a, b, c) for (ll i = (ll)(a); i < (ll)(b); i += (ll)(c))
#define rep(...) REP_SELECTER(__VA_ARGS__, REP4, REP3, REP2, REP1)(__VA_ARGS__)
#define RREP2(i, a) for (ll i = (ll)(a)-1; i >= 0; --i)
#define RREP3(i, a, b) for (ll i = (ll)(a)-1; i >= (ll)(b); --i)
#define RREP4(i, a, b, c) for (ll i = (ll)(a)-1; i >= (ll)(b); i -= (ll)(c))
#define rrep(...) REP_SELECTER(__VA_ARGS__, RREP4, RREP3, RREP2)(__VA_ARGS__)
#define REPS2(i, b) for (ll i = 1; i <= (ll)(b); ++i)
#define REPS3(i, a, b) for (ll i = (ll)(a) + 1; i <= (ll)(b); ++i)
#define REPS4(i, a, b, c) for (ll i = (ll)(a) + 1; i <= (ll)(b); i += (ll)(c))
#define reps(...) REP_SELECTER(__VA_ARGS__, REPS4, REPS3, REPS2)(__VA_ARGS__)
#define RREPS2(i, a) for (ll i = (ll)(a); i > 0; --i)
#define RREPS3(i, a, b) for (ll i = (ll)(a); i > (ll)(b); --i)
#define RREPS4(i, a, b, c) for (ll i = (ll)(a); i > (ll)(b); i -= (ll)(c))
#define rreps(...) \
REP_SELECTER(__VA_ARGS__, RREPS4, RREPS3, RREPS2)(__VA_ARGS__)
#define each_for(...) for (auto&& __VA_ARGS__)
#define each_const(...) for (const auto& __VA_ARGS__)
#define all(v) std::begin(v), std::end(v)
#if __cplusplus >= 201402L
#define rall(v) std::rbegin(v), std::rend(v)
#else
#define rall(v) v.rbegin(), v.rend()
#endif
#if __cpp_constexpr >= 201304L
#define CONSTEXPR constexpr
#else
#define CONSTEXPR
#endif
#if __cpp_if_constexpr >= 201606L
#define IF_CONSTEXPR constexpr
#else
#define IF_CONSTEXPR
#endif
#define IO_BUFFER_SIZE 2048
#line 2 "library/template/alias.hpp"
#line 4 "library/template/alias.hpp"
using ll = long long;
using ull = unsigned long long;
using ld = long double;
using PLL = std::pair<ll, ll>;
template<class T>
using prique = std::priority_queue<T, std::vector<T>, std::greater<T>>;
template<class T> class infinity {
public:
static constexpr T value = std::numeric_limits<T>::max() / 2;
static constexpr T mvalue = std::numeric_limits<T>::min() / 2;
static constexpr T max = std::numeric_limits<T>::max();
static constexpr T min = std::numeric_limits<T>::min();
};
#if __cplusplus <= 201402L
template<class T> constexpr T infinity<T>::value;
template<class T> constexpr T infinity<T>::mvalue;
template<class T> constexpr T infinity<T>::max;
template<class T> constexpr T infinity<T>::min;
#endif
#if __cpp_variable_templates >= 201304L
template<class T> constexpr T INF = infinity<T>::value;
#endif
constexpr ll inf = infinity<ll>::value;
constexpr ld EPS = 1e-8;
constexpr ld PI = 3.1415926535897932384626;
#line 2 "library/template/type_traits.hpp"
#line 5 "library/template/type_traits.hpp"
template<class T, class... Args> struct function_traits_impl {
using result_type = T;
template<std::size_t idx>
using argument_type =
typename std::tuple_element<idx, std::tuple<Args...>>::type;
using argument_tuple = std::tuple<Args...>;
static constexpr std::size_t arg_size() { return sizeof...(Args); }
};
template<class> struct function_traits_helper;
template<class Res, class Tp, class... Args>
struct function_traits_helper<Res (Tp::*)(Args...)> {
using type = function_traits_impl<Res, Args...>;
};
template<class Res, class Tp, class... Args>
struct function_traits_helper<Res (Tp::*)(Args...)&> {
using type = function_traits_impl<Res, Args...>;
};
template<class Res, class Tp, class... Args>
struct function_traits_helper<Res (Tp::*)(Args...) const> {
using type = function_traits_impl<Res, Args...>;
};
template<class Res, class Tp, class... Args>
struct function_traits_helper<Res (Tp::*)(Args...) const&> {
using type = function_traits_impl<Res, Args...>;
};
#if __cpp_noexcept_function_type >= 201510L
template<class Res, class Tp, class... Args>
struct function_traits_helper<Res (Tp::*)(Args...) noexcept> {
using type = function_traits_impl<Res, Args...>;
};
template<class Res, class Tp, class... Args>
struct function_traits_helper<Res (Tp::*)(Args...)& noexcept> {
using type = function_traits_impl<Res, Args...>;
};
template<class Res, class Tp, class... Args>
struct function_traits_helper<Res (Tp::*)(Args...) const noexcept> {
using type = function_traits_impl<Res, Args...>;
};
template<class Res, class Tp, class... Args>
struct function_traits_helper<Res (Tp::*)(Args...) const& noexcept> {
using type = function_traits_impl<Res, Args...>;
};
#endif
template<class F>
using function_traits =
typename function_traits_helper<decltype(&F::operator())>::type;
template<class T>
using is_signed_int =
std::disjunction<std::conjunction<std::is_integral<T>, std::is_signed<T>>,
std::is_same<T, __int128_t>>;
template<class T>
using is_unsigned_int =
std::disjunction<std::conjunction<std::is_integral<T>, std::is_unsigned<T>>,
std::is_same<T, __uint128_t>>;
template<class T>
using is_int = std::disjunction<is_signed_int<T>, is_unsigned_int<T>>;
template<class T>
using make_signed_int = typename std::conditional<
std::is_same<T, __int128_t>::value || std::is_same<T, __uint128_t>::value,
std::common_type<__int128_t>, std::make_signed<T>>::type;
template<class T>
using make_unsigned_int = typename std::conditional<
std::is_same<T, __int128_t>::value || std::is_same<T, __uint128_t>::value,
std::common_type<__uint128_t>, std::make_unsigned<T>>::type;
template<class T, class = void> struct is_range : std::false_type {};
template<class T>
struct is_range<
T,
decltype(all(std::declval<typename std::add_lvalue_reference<T>::type>()),
(void)0)> : std::true_type {};
template<class T, bool = is_range<T>::value>
struct range_rank : std::integral_constant<std::size_t, 0> {};
template<class T>
struct range_rank<T, true>
: std::integral_constant<std::size_t,
range_rank<typename T::value_type>::value + 1> {};
template<std::size_t size> struct int_least {
static_assert(size <= 128, "size must be less than or equal to 128");
using type = typename std::conditional<
size <= 8, std::int_least8_t,
typename std::conditional<
size <= 16, std::int_least16_t,
typename std::conditional<
size <= 32, std::int_least32_t,
typename std::conditional<size <= 64, std::int_least64_t,
__int128_t>::type>::type>::type>::
type;
};
template<std::size_t size> using int_least_t = typename int_least<size>::type;
template<std::size_t size> struct uint_least {
static_assert(size <= 128, "size must be less than or equal to 128");
using type = typename std::conditional<
size <= 8, std::uint_least8_t,
typename std::conditional<
size <= 16, std::uint_least16_t,
typename std::conditional<
size <= 32, std::uint_least32_t,
typename std::conditional<size <= 64, std::uint_least64_t,
__uint128_t>::type>::type>::type>::
type;
};
template<std::size_t size> using uint_least_t = typename uint_least<size>::type;
template<class T>
using double_size_int = int_least<std::numeric_limits<T>::digits * 2 + 1>;
template<class T> using double_size_int_t = typename double_size_int<T>::type;
template<class T>
using double_size_uint = uint_least<std::numeric_limits<T>::digits * 2>;
template<class T> using double_size_uint_t = typename double_size_uint<T>::type;
template<class T>
using double_size =
typename std::conditional<is_signed_int<T>::value, double_size_int<T>,
double_size_uint<T>>::type;
template<class T> using double_size_t = typename double_size<T>::type;
#line 2 "library/template/in.hpp"
#line 4 "library/template/in.hpp"
#include <unistd.h>
#line 8 "library/template/in.hpp"
template<std::size_t buf_size = IO_BUFFER_SIZE> class Reader {
private:
int fd, idx, sz;
bool state;
std::array<char, buf_size> buffer;
inline void read_buf() {
sz = read(fd, buffer.begin(), buf_size);
idx = 0;
if (sz < 0) throw std::runtime_error("input failed");
}
public:
static constexpr int get_buf_size() { return buf_size; }
Reader() noexcept : fd(0), idx(0), sz(0), state(true) {}
Reader(int fd) noexcept : fd(fd), idx(0), sz(0), state(true) {}
Reader(FILE* fp) noexcept : fd(fileno(fp)), idx(0), sz(0), state(true) {}
class iterator {
private:
Reader* reader;
public:
using difference_type = void;
using value_type = void;
using pointer = void;
using reference = void;
using iterator_category = std::input_iterator_tag;
iterator() : reader(nullptr) {}
explicit iterator(Reader& reader) : reader(&reader) {}
explicit iterator(Reader* reader) : reader(reader) {}
iterator& operator++() {
if (reader->idx == reader->sz) reader->read_buf();
++reader->idx;
return *this;
}
iterator operator++(int) {
iterator res = *this;
++(*this);
return res;
}
char operator*() const {
if (reader->idx == reader->sz) reader->read_buf();
if (reader->idx < reader->sz) return reader->buffer[reader->idx];
reader->state = false;
return '\0';
}
bool rdstate() const { return reader->state; }
};
iterator begin() noexcept { return iterator(this); }
};
Reader<> reader(0);
template<class Iterator, std::size_t decimal_precision = 16> class Scanner {
public:
using iterator_type = Iterator;
private:
template<class, class = void> struct has_scan : std::false_type {};
template<class T>
struct has_scan<
T, decltype(std::declval<T>().scan(std::declval<Scanner&>()), (void)0)>
: std::true_type {};
Iterator itr;
public:
Scanner() = default;
Scanner(const Iterator& itr) : itr(itr) {}
char scan_char() {
char c = *itr;
++itr;
return c;
}
Scanner ignore(int n = 1) {
rep (n) ++itr;
return *this;
}
inline void discard_space() {
while (('\t' <= *itr && *itr <= '\r') || *itr == ' ') ++itr;
}
void scan(char& a) {
discard_space();
a = *itr;
++itr;
}
void scan(bool& a) {
discard_space();
a = *itr != '0';
++itr;
}
void scan(std::string& a) {
discard_space();
a.clear();
while ((*itr < '\t' || '\r' < *itr) && *itr != ' ' && *itr != '\0') {
a += *itr;
++itr;
}
}
template<std::size_t len> void scan(std::bitset<len>& a) {
discard_space();
rrep (i, len) {
a[i] = *itr != '0';
++itr;
}
}
template<class T,
typename std::enable_if<is_signed_int<T>::value &&
!has_scan<T>::value>::type* = nullptr>
void scan(T& a) {
discard_space();
if (*itr == '-') {
++itr;
a = 0;
while ('0' <= *itr && *itr <= '9') {
a = a * 10 - (*itr - '0');
++itr;
}
}
else {
a = 0;
while ('0' <= *itr && *itr <= '9') {
a = a * 10 + (*itr - '0');
++itr;
}
}
}
template<class T,
typename std::enable_if<is_unsigned_int<T>::value &&
!has_scan<T>::value>::type* = nullptr>
void scan(T& a) {
discard_space();
a = 0;
while ('0' <= *itr && *itr <= '9') {
a = a * 10 + *itr - '0';
++itr;
}
}
template<class T,
typename std::enable_if<std::is_floating_point<T>::value &&
!has_scan<T>::value>::type* = nullptr>
void scan(T& a) {
discard_space();
bool sgn = false;
if (*itr == '-') {
sgn = true;
++itr;
}
a = 0;
while ('0' <= *itr && *itr <= '9') {
a = a * 10 + *itr - '0';
++itr;
}
if (*itr == '.') {
++itr;
T n = 0, d = 1;
for (int i = 0;
'0' <= *itr && *itr <= '9' && i < (int)decimal_precision;
++i) {
n = n * 10 + *itr - '0';
d *= 10;
++itr;
}
while ('0' <= *itr && *itr <= '9') ++itr;
a += n / d;
}
if (sgn) a = -a;
}
private:
template<std::size_t i, class... Args> void scan(std::tuple<Args...>& a) {
if IF_CONSTEXPR (i < sizeof...(Args)) {
scan(std::get<i>(a));
scan<i + 1, Args...>(a);
}
}
public:
template<class... Args> void scan(std::tuple<Args...>& a) {
scan<0, Args...>(a);
}
template<class T, class U> void scan(std::pair<T, U>& a) {
scan(a.first);
scan(a.second);
}
template<class T,
typename std::enable_if<is_range<T>::value &&
!has_scan<T>::value>::type* = nullptr>
void scan(T& a) {
each_for (i : a) scan(i);
}
template<class T,
typename std::enable_if<has_scan<T>::value>::type* = nullptr>
void scan(T& a) {
a.scan(*this);
}
void operator()() {}
template<class Head, class... Args>
void operator()(Head& head, Args&... args) {
scan(head);
operator()(args...);
}
template<class T> Scanner& operator>>(T& a) {
scan(a);
return *this;
}
explicit operator bool() const { return itr.rdstate(); }
};
Scanner<Reader<>::iterator> scan(reader.begin());
template<class Iterator, std::size_t decimal_precision>
Scanner<Iterator, decimal_precision>&
getline(Scanner<Iterator, decimal_precision>& scan, std::string& a) {
a.clear();
char c;
while ((c = scan.scan_char()) != '\n') {
a += c;
}
return scan;
}
#line 2 "library/template/out.hpp"
#line 8 "library/template/out.hpp"
template<std::size_t buf_size = IO_BUFFER_SIZE> class Writer {
private:
int fd, idx;
std::array<char, buf_size> buffer;
inline void write_buf() {
int num = write(fd, buffer.begin(), idx);
idx = 0;
if (num < 0) throw std::runtime_error("output failed");
}
public:
Writer() noexcept : fd(1), idx(0) {}
Writer(int fd) noexcept : fd(fd), idx(0) {}
Writer(FILE* fp) noexcept : fd(fileno(fp)), idx(0) {}
~Writer() { write_buf(); }
class iterator {
private:
Writer* writer;
public:
using difference_type = void;
using value_type = void;
using pointer = void;
using reference = void;
using iterator_category = std::output_iterator_tag;
iterator() noexcept : writer(nullptr) {}
explicit iterator(Writer& writer) noexcept : writer(&writer) {}
explicit iterator(Writer* writer) noexcept : writer(writer) {}
iterator& operator++() {
++writer->idx;
if (writer->idx == buf_size) writer->write_buf();
return *this;
}
iterator operator++(int) {
iterator res = *this;
++(*this);
return res;
}
char& operator*() const { return writer->buffer[writer->idx]; }
void flush() const { writer->write_buf(); }
};
iterator begin() noexcept { return iterator(this); }
};
Writer<> writer(1), ewriter(2);
template<class Iterator, bool debug = false> class Printer {
public:
using iterator_type = Iterator;
private:
template<class, bool = debug, class = void>
struct has_print : std::false_type {};
template<class T>
struct has_print<T, false,
decltype(std::declval<T>().print(std::declval<Printer&>()),
(void)0)> : std::true_type {};
template<class T>
struct has_print<T, true,
decltype(std::declval<T>().debug(std::declval<Printer&>()),
(void)0)> : std::true_type {};
Iterator itr;
std::size_t decimal_precision;
public:
void print_char(char c) {
*itr = c;
++itr;
}
void flush() { itr.flush(); }
Printer() noexcept = default;
explicit Printer(const Iterator& itr) noexcept
: itr(itr), decimal_precision(16) {}
void set_decimal_precision(std::size_t decimal_precision) {
this->decimal_precision = decimal_precision;
}
void print(char c) {
if IF_CONSTEXPR (debug) print_char('\'');
print_char(c);
if IF_CONSTEXPR (debug) print_char('\'');
}
void print(bool b) { print_char((char)(b + '0')); }
void print(const char* a) {
if IF_CONSTEXPR (debug) print_char('"');
for (; *a != '\0'; ++a) print_char(*a);
if IF_CONSTEXPR (debug) print_char('"');
}
template<std::size_t len> void print(const char (&a)[len]) {
if IF_CONSTEXPR (debug) print_char('"');
for (auto i : a) print_char(i);
if IF_CONSTEXPR (debug) print_char('"');
}
void print(const std::string& a) {
if IF_CONSTEXPR (debug) print_char('"');
for (auto i : a) print_char(i);
if IF_CONSTEXPR (debug) print_char('"');
}
template<std::size_t len> void print(const std::bitset<len>& a) {
rrep (i, len) print_char((char)(a[i] + '0'));
}
template<class T,
typename std::enable_if<is_int<T>::value &&
!has_print<T>::value>::type* = nullptr>
void print(T a) {
if (!a) {
print_char('0');
return;
}
if IF_CONSTEXPR (is_signed_int<T>::value) {
if (a < 0) {
print_char('-');
using U = typename make_unsigned_int<T>::type;
print(static_cast<U>(-static_cast<U>(a)));
return;
}
}
std::string s;
while (a) {
s += (char)(a % 10 + '0');
a /= 10;
}
for (auto i = s.rbegin(); i != s.rend(); ++i) print_char(*i);
}
template<class T,
typename std::enable_if<std::is_floating_point<T>::value &&
!has_print<T>::value>::type* = nullptr>
void print(T a) {
if (a == std::numeric_limits<T>::infinity()) {
print("inf");
return;
}
if (a == -std::numeric_limits<T>::infinity()) {
print("-inf");
return;
}
if (std::isnan(a)) {
print("nan");
return;
}
if (a < 0) {
print_char('-');
a = -a;
}
T b = a;
if (b < 1) {
print_char('0');
}
else {
std::string s;
while (b >= 1) {
s += (char)('0' + (int)std::fmod(b, 10.0));
b /= 10;
}
for (auto i = s.rbegin(); i != s.rend(); ++i) print_char(*i);
}
print_char('.');
rep (decimal_precision) {
a *= 10;
print_char((char)('0' + (int)std::fmod(a, 10.0)));
}
}
private:
template<std::size_t i, class... Args>
void print(const std::tuple<Args...>& a) {
if IF_CONSTEXPR (i < sizeof...(Args)) {
if IF_CONSTEXPR (debug) print_char(',');
print_char(' ');
print(std::get<i>(a));
print<i + 1, Args...>(a);
}
}
public:
template<class... Args> void print(const std::tuple<Args...>& a) {
if IF_CONSTEXPR (debug) print_char('(');
if IF_CONSTEXPR (sizeof...(Args) != 0) print(std::get<0>(a));
print<1, Args...>(a);
if IF_CONSTEXPR (debug) print_char(')');
}
template<class T, class U> void print(const std::pair<T, U>& a) {
if IF_CONSTEXPR (debug) print_char('(');
print(a.first);
if IF_CONSTEXPR (debug) print_char(',');
print_char(' ');
print(a.second);
if IF_CONSTEXPR (debug) print_char(')');
}
template<class T,
typename std::enable_if<is_range<T>::value &&
!has_print<T>::value>::type* = nullptr>
void print(const T& a) {
if IF_CONSTEXPR (debug) print_char('{');
for (auto i = std::begin(a); i != std::end(a); ++i) {
if (i != std::begin(a)) {
if IF_CONSTEXPR (debug) print_char(',');
print_char(' ');
}
print(*i);
}
if IF_CONSTEXPR (debug) print_char('}');
}
template<class T, typename std::enable_if<has_print<T>::value &&
!debug>::type* = nullptr>
void print(const T& a) {
a.print(*this);
}
template<class T, typename std::enable_if<has_print<T>::value &&
debug>::type* = nullptr>
void print(const T& a) {
a.debug(*this);
}
void operator()() {}
template<class Head, class... Args>
void operator()(const Head& head, const Args&... args) {
print(head);
operator()(args...);
}
template<class T> Printer& operator<<(const T& a) {
print(a);
return *this;
}
Printer& operator<<(Printer& (*pf)(Printer&)) { return pf(*this); }
};
template<class Iterator, bool debug>
Printer<Iterator, debug>& endl(Printer<Iterator, debug>& pr) {
pr.print_char('\n');
pr.flush();
return pr;
}
template<class Iterator, bool debug>
Printer<Iterator, debug>& flush(Printer<Iterator, debug>& pr) {
pr.flush();
return pr;
}
struct SetPrec {
int n;
template<class Pr> void print(Pr& pr) const { pr.set_decimal_precision(n); }
template<class Pr> void debug(Pr& pr) const { pr.set_decimal_precision(n); }
};
SetPrec setprec(int n) { return SetPrec{n}; };
Printer<Writer<>::iterator> print(writer.begin()), eprint(ewriter.begin());
template<class T> auto prints(const T& v) -> decltype(print << v, (void)0) {
print << v;
print.print_char('\n');
}
template<class Head, class... Tail>
auto prints(const Head& head, const Tail&... tail)
-> decltype(print << head, (void)0) {
print << head;
print.print_char(' ');
prints(tail...);
}
#ifdef SHIO_LOCAL
Printer<Writer<>::iterator, true> debug(writer.begin()),
edebug(ewriter.begin());
#else
char debug_iterator_character;
class DebugIterator {
public:
DebugIterator() noexcept = default;
DebugIterator& operator++() { return *this; }
DebugIterator& operator++(int) { return *this; }
char& operator*() const { return debug_iterator_character; }
void flush() const {}
};
Printer<DebugIterator> debug, edebug;
#endif
template<class T> auto debugs(const T& v) -> decltype(debug << v, (void)0) {
debug << v;
debug.print_char('\n');
}
template<class Head, class... Tail>
auto debugs(const Head& head, const Tail&... tail)
-> decltype(debug << head, (void)0) {
debug << head;
debug.print_char(' ');
debugs(tail...);
}
#line 2 "library/template/bitop.hpp"
#line 6 "library/template/bitop.hpp"
namespace bitop {
#define KTH_BIT(b, k) (((b) >> (k)) & 1)
#define POW2(k) (1ull << (k))
inline ull next_combination(int n, ull x) {
if (n == 0) return 1;
ull a = x & -x;
ull b = x + a;
return (x & ~b) / a >> 1 | b;
}
#define rep_comb(i, n, k) \
for (ull i = (1ull << (k)) - 1; i < (1ull << (n)); \
i = bitop::next_combination((n), i))
inline CONSTEXPR int msb(ull x) {
int res = x ? 0 : -1;
if (x & 0xFFFFFFFF00000000) x &= 0xFFFFFFFF00000000, res += 32;
if (x & 0xFFFF0000FFFF0000) x &= 0xFFFF0000FFFF0000, res += 16;
if (x & 0xFF00FF00FF00FF00) x &= 0xFF00FF00FF00FF00, res += 8;
if (x & 0xF0F0F0F0F0F0F0F0) x &= 0xF0F0F0F0F0F0F0F0, res += 4;
if (x & 0xCCCCCCCCCCCCCCCC) x &= 0xCCCCCCCCCCCCCCCC, res += 2;
return res + ((x & 0xAAAAAAAAAAAAAAAA) ? 1 : 0);
}
inline CONSTEXPR int ceil_log2(ull x) { return x ? msb(x - 1) + 1 : 0; }
inline CONSTEXPR ull reverse(ull x) {
x = ((x & 0xAAAAAAAAAAAAAAAA) >> 1) | ((x & 0x5555555555555555) << 1);
x = ((x & 0xCCCCCCCCCCCCCCCC) >> 2) | ((x & 0x3333333333333333) << 2);
x = ((x & 0xF0F0F0F0F0F0F0F0) >> 4) | ((x & 0x0F0F0F0F0F0F0F0F) << 4);
x = ((x & 0xFF00FF00FF00FF00) >> 8) | ((x & 0x00FF00FF00FF00FF) << 8);
x = ((x & 0xFFFF0000FFFF0000) >> 16) | ((x & 0x0000FFFF0000FFFF) << 16);
return (x >> 32) | (x << 32);
}
inline CONSTEXPR ull reverse(ull x, int n) { return reverse(x) >> (64 - n); }
} // namespace bitop
inline CONSTEXPR int popcnt(ull x) noexcept {
#if __cplusplus >= 202002L
return std::popcount(x);
#endif
x = (x & 0x5555555555555555) + ((x >> 1) & 0x5555555555555555);
x = (x & 0x3333333333333333) + ((x >> 2) & 0x3333333333333333);
x = (x & 0x0f0f0f0f0f0f0f0f) + ((x >> 4) & 0x0f0f0f0f0f0f0f0f);
x = (x & 0x00ff00ff00ff00ff) + ((x >> 8) & 0x00ff00ff00ff00ff);
x = (x & 0x0000ffff0000ffff) + ((x >> 16) & 0x0000ffff0000ffff);
return (x & 0x00000000ffffffff) + ((x >> 32) & 0x00000000ffffffff);
}
#line 2 "library/template/func.hpp"
#line 6 "library/template/func.hpp"
template<class T, class U, class Comp = std::less<>>
inline constexpr bool chmin(T& a, const U& b,
Comp cmp = Comp()) noexcept(noexcept(cmp(b, a))) {
return cmp(b, a) ? a = b, true : false;
}
template<class T, class U, class Comp = std::less<>>
inline constexpr bool chmax(T& a, const U& b,
Comp cmp = Comp()) noexcept(noexcept(cmp(a, b))) {
return cmp(a, b) ? a = b, true : false;
}
inline CONSTEXPR ll gcd(ll a, ll b) noexcept {
if (a < 0) a = -a;
if (b < 0) b = -b;
while (b) {
const ll c = a;
a = b;
b = c % b;
}
return a;
}
inline CONSTEXPR ll lcm(ll a, ll b) noexcept { return a / gcd(a, b) * b; }
inline CONSTEXPR bool is_prime(ll N) noexcept {
if (N <= 1) return false;
for (ll i = 2; i * i <= N; ++i) {
if (N % i == 0) return false;
}
return true;
}
inline std::vector<ll> prime_factor(ll N) {
std::vector<ll> res;
for (ll i = 2; i * i <= N; ++i) {
while (N % i == 0) {
res.push_back(i);
N /= i;
}
}
if (N != 1) res.push_back(N);
return res;
}
inline CONSTEXPR ll my_pow(ll a, ll b) noexcept {
ll res = 1;
while (b) {
if (b & 1) res *= a;
b >>= 1;
a *= a;
}
return res;
}
inline CONSTEXPR ll mod_pow(ll a, ll b, ll mod) {
assert(mod > 0);
if (mod == 1) return 0;
a %= mod;
ll res = 1;
while (b) {
if (b & 1) (res *= a) %= mod;
b >>= 1;
(a *= a) %= mod;
}
return res;
}
inline PLL extGCD(ll a, ll b) {
const ll n = a, m = b;
ll x = 1, y = 0, u = 0, v = 1;
ll t;
while (b) {
t = a / b;
std::swap(a -= t * b, b);
std::swap(x -= t * u, u);
std::swap(y -= t * v, v);
}
if (x < 0) {
x += m;
y -= n;
}
return {x, y};
}
inline ll mod_inv(ll a, ll mod) {
ll b = mod;
ll x = 1, u = 0;
ll t;
while (b) {
t = a / b;
std::swap(a -= t * b, b);
std::swap(x -= t * u, u);
}
if (x < 0) x += mod;
assert(a == 1);
return x;
}
#line 2 "library/template/util.hpp"
#line 6 "library/template/util.hpp"
template<class F> class RecLambda {
private:
F f;
public:
explicit constexpr RecLambda(F&& f_) : f(std::forward<F>(f_)) {}
template<class... Args>
constexpr auto operator()(Args&&... args)
-> decltype(f(*this, std::forward<Args>(args)...)) {
return f(*this, std::forward<Args>(args)...);
}
};
template<class F> inline constexpr RecLambda<F> rec_lambda(F&& f) {
return RecLambda<F>(std::forward<F>(f));
}
template<class Head, class... Tail> struct multi_dim_vector {
using type = std::vector<typename multi_dim_vector<Tail...>::type>;
};
template<class T> struct multi_dim_vector<T> { using type = T; };
template<class T, class Arg>
constexpr std::vector<T> make_vec(int n, Arg&& arg) {
return std::vector<T>(n, std::forward<Arg>(arg));
}
template<class T, class... Args>
constexpr typename multi_dim_vector<Args..., T>::type make_vec(int n,
Args&&... args) {
return typename multi_dim_vector<Args..., T>::type(
n, make_vec<T>(std::forward<Args>(args)...));
}
template<class T, class Comp = std::less<T>> class presser {
private:
std::vector<T> dat;
Comp cmp;
bool sorted = false;
public:
presser() : presser(Comp()) {}
presser(const Comp& cmp) : cmp(cmp) {}
presser(const std::vector<T>& vec, const Comp& cmp = Comp())
: dat(vec), cmp(cmp) {}
presser(std::vector<T>&& vec, const Comp& cmp = Comp())
: dat(std::move(vec)), cmp(cmp) {}
presser(std::initializer_list<T> il, const Comp& cmp = Comp())
: dat(all(il)), cmp(cmp) {}
void reserve(int n) {
assert(!sorted);
dat.reserve(n);
}
void push_back(const T& v) {
assert(!sorted);
dat.push_back(v);
}
void push_back(T&& v) {
assert(!sorted);
dat.push_back(std::move(v));
}
template<class... Args> void emplace_back(Args&&... args) {
assert(!sorted);
dat.emplace_back(std::forward<Args>(args)...);
}
void push(const std::vector<T>& vec) {
assert(!sorted);
const int n = dat.size();
dat.resize(n + vec.size());
rep (i, vec.size()) dat[n + i] = vec[i];
}
int build() {
assert(!sorted);
sorted = true;
std::sort(all(dat), cmp);
dat.erase(std::unique(all(dat),
[&](const T& a, const T& b) -> bool {
return !cmp(a, b) && !cmp(b, a);
}),
dat.end());
return dat.size();
}
const T& operator[](int k) const& {
assert(sorted);
assert(0 <= k && k < (int)dat.size());
return dat[k];
}
T operator[](int k) && {
assert(sorted);
assert(0 <= k && k < (int)dat.size());
return std::move(dat[k]);
}
int get(const T& val) const {
assert(sorted);
auto itr = std::lower_bound(all(dat), val, cmp);
assert(itr != dat.end() && !cmp(val, *itr));
return itr - dat.begin();
}
int lower_bound(const T& val) const {
assert(sorted);
auto itr = std::lower_bound(all(dat), val, cmp);
return itr - dat.begin();
}
int upper_bound(const T& val) const {
assert(sorted);
auto itr = std::upper_bound(all(dat), val, cmp);
return itr - dat.begin();
}
bool contains(const T& val) const {
assert(sorted);
return std::binary_search(all(dat), val, cmp);
}
std::vector<int> pressed(const std::vector<T>& vec) const {
assert(sorted);
std::vector<int> res(vec.size());
rep (i, vec.size()) res[i] = get(vec[i]);
return res;
}
void press(std::vector<T>& vec) const {
static_assert(std::is_convertible<T, int>::value,
"template argument must be convertible from int type");
assert(sorted);
each_for (i : vec) i = get(i);
}
int size() const {
assert(sorted);
return dat.size();
}
const std::vector<T>& data() const& { return dat; }
std::vector<T> data() && { return std::move(dat); }
};
#line 2 "library/graph/tree/ReRooting.hpp"
#line 2 "library/graph/Graph.hpp"
#line 4 "library/graph/Graph.hpp"
template<class T = int> struct edge {
int from, to;
T cost;
int idx;
edge() : from(-1), to(-1) {}
edge(int f, int t, const T& c = 1, int i = -1)
: from(f), to(t), cost(c), idx(i) {}
edge(int f, int t, T&& c, int i = -1)
: from(f), to(t), cost(std::move(c)), idx(i) {}
operator int() const { return to; }
friend bool operator<(const edge<T>& lhs, const edge<T>& rhs) {
return lhs.cost < rhs.cost;
}
friend bool operator>(const edge<T>& lhs, const edge<T>& rhs) {
return lhs.cost > rhs.cost;
}
};
template<class T = int> using Edges = std::vector<edge<T>>;
template<class T = int> using GMatrix = std::vector<std::vector<T>>;
template<class T = int> class Graph : public std::vector<std::vector<edge<T>>> {
private:
using Base = std::vector<std::vector<edge<T>>>;
public:
int edge_id = 0;
using Base::Base;
int edge_size() const { return edge_id; }
int add_edge(int a, int b, const T& c, bool is_directed = false) {
assert(0 <= a && a < (int)this->size());
assert(0 <= b && b < (int)this->size());
(*this)[a].emplace_back(a, b, c, edge_id);
if (!is_directed) (*this)[b].emplace_back(b, a, c, edge_id);
return edge_id++;
}
int add_edge(int a, int b, bool is_directed = false) {
assert(0 <= a && a < (int)this->size());
assert(0 <= b && b < (int)this->size());
(*this)[a].emplace_back(a, b, 1, edge_id);
if (!is_directed) (*this)[b].emplace_back(b, a, 1, edge_id);
return edge_id++;
}
};
template<class T> GMatrix<T> ListToMatrix(const Graph<T>& G) {
const int N = G.size();
auto res = make_vec<T>(N, N, infinity<T>::value);
rep (i, N) res[i][i] = 0;
rep (i, N) {
each_const (e : G[i]) res[i][e.to] = e.cost;
}
return res;
}
template<class T> Edges<T> UndirectedListToEdges(const Graph<T>& G) {
const int V = G.size();
const int E = G.edge_size();
Edges<T> Ed(E);
rep (i, V) {
each_const (e : G[i]) Ed[e.idx] = e;
}
return Ed;
}
template<class T> Edges<T> DirectedListToEdges(const Graph<T>& G) {
const int V = G.size();
const int E = std::accumulate(
all(G), 0, [](int a, const std::vector<edge<T>>& v) -> int {
return a + v.size();
});
Edges<T> Ed(G.edge_size());
Ed.reserve(E);
rep (i, V) {
each_const (e : G[i]) {
if (Ed[e.idx] == -1) Ed[e.idx] = e;
else Ed.push_back(e);
}
}
return Ed;
}
template<class T> Graph<T> ReverseGraph(const Graph<T>& G) {
const int V = G.size();
Graph<T> res(V);
rep (i, V) {
each_const (e : G[i]) {
res[e.to].emplace_back(e.to, e.from, e.cost, e.idx);
}
}
res.edge_id = G.edge_size();
return res;
}
struct unweighted_edge {
template<class... Args> unweighted_edge(const Args&...) {}
operator int() { return 1; }
};
using UnweightedGraph = Graph<unweighted_edge>;
/**
* @brief Graph-template
* @docs docs/graph/Graph.md
*/
#line 4 "library/graph/tree/ReRooting.hpp"
#line 2 "library/other/monoid.hpp"
#line 4 "library/other/monoid.hpp"
namespace Monoid {
template<class M, class = void> class has_op : public std::false_type {};
template<class M>
class has_op<M, decltype((void)M::op)> : public std::true_type {};
template<class M, class = void> class has_id : public std::false_type {};
template<class M>
class has_id<M, decltype((void)M::id)> : public std::true_type {};
template<class M, class = void> class has_inv : public std::false_type {};
template<class M>
class has_inv<M, decltype((void)M::inv)> : public std::true_type {};
template<class M, class = void> class has_get_inv : public std::false_type {};
template<class M>
class has_get_inv<M, decltype((void)M::get_inv)> : public std::true_type {};
template<class M, class = void> class has_init : public std::false_type {};
template<class M>
class has_init<M, decltype((void)M::init(0, 0))> : public std::true_type {};
template<class A, class = void> class has_mul_op : public std::false_type {};
template<class A>
class has_mul_op<A, decltype((void)A::mul_op)> : public std::true_type {};
template<class T, class = void> class is_semigroup : public std::false_type {};
template<class T>
class is_semigroup<T, decltype(std::declval<typename T::value_type>(),
(void)T::op)> : public std::true_type {};
template<class T, class = void> class is_monoid : public std::false_type {};
template<class T>
class is_monoid<T, decltype(std::declval<typename T::value_type>(), (void)T::op,
(void)T::id)> : public std::true_type {};
template<class T, class = void> class is_group : public std::false_type {};
template<class T>
class is_group<T, decltype(std::declval<typename T::value_type>(), (void)T::op,
(void)T::id, (void)T::get_inv)>
: public std::true_type {};
template<class T, class = void> class is_action : public std::false_type {};
template<class T>
class is_action<T, typename std::enable_if<is_monoid<typename T::M>::value &&
is_semigroup<typename T::E>::value &&
(has_op<T>::value ||
has_mul_op<T>::value)>::type>
: public std::true_type {};
template<class T, class = void>
class is_distributable_action : public std::false_type {};
template<class T>
class is_distributable_action<
T,
typename std::enable_if<is_action<T>::value && !has_mul_op<T>::value>::type>
: public std::true_type {};
template<class T> struct Sum {
using value_type = T;
static constexpr T op(const T& a, const T& b) { return a + b; }
static constexpr T id() { return T{0}; }
static constexpr T inv(const T& a, const T& b) { return a - b; }
static constexpr T get_inv(const T& a) { return -a; }
};
template<class T, T max_value = infinity<T>::max> struct Min {
using value_type = T;
static constexpr T op(const T& a, const T& b) { return a < b ? a : b; }
static constexpr T id() { return max_value; }
};
template<class T, T min_value = infinity<T>::min> struct Max {
using value_type = T;
static constexpr T op(const T& a, const T& b) { return a < b ? b : a; }
static constexpr T id() { return min_value; }
};
template<class T> struct Assign {
using value_type = T;
static constexpr T op(const T&, const T& b) { return b; }
};
template<class T, T max_value = infinity<T>::max> struct AssignMin {
using M = Min<T, max_value>;
using E = Assign<T>;
static constexpr T op(const T& a, const T&) { return a; }
};
template<class T, T min_value = infinity<T>::min> struct AssignMax {
using M = Max<T, min_value>;
using E = Assign<T>;
static constexpr T op(const T& a, const T&) { return a; }
};
template<class T> struct AssignSum {
using M = Sum<T>;
using E = Assign<T>;
static constexpr T mul_op(const T& a, int b, const T&) { return a * b; }
};
template<class T, T max_value = infinity<T>::max> struct AddMin {
using M = Min<T, max_value>;
using E = Sum<T>;
static constexpr T op(const T& a, const T& b) { return b + a; }
};
template<class T, T min_value = infinity<T>::min> struct AddMax {
using M = Max<T, min_value>;
using E = Sum<T>;
static constexpr T op(const T& a, const T& b) { return b + a; }
};
template<class T> struct AddSum {
using M = Sum<T>;
using E = Sum<T>;
static constexpr T mul_op(const T& a, int b, const T& c) {
return c + a * b;
}
};
template<class T, T max_value = infinity<T>::max> struct ChminMin {
using M = Min<T, max_value>;
using E = Min<T>;
static constexpr T op(const T& a, const T& b) { return std::min(b, a); }
};
template<class T, T min_value = infinity<T>::min> struct ChminMax {
using M = Max<T, min_value>;
using E = Min<T>;
static constexpr T op(const T& a, const T& b) { return std::min(b, a); }
};
template<class T, T max_value = infinity<T>::max> struct ChmaxMin {
using M = Min<T, max_value>;
using E = Max<T>;
static constexpr T op(const T& a, const T& b) { return std::max(b, a); }
};
template<class T, T min_value = infinity<T>::min> struct ChmaxMax {
using M = Max<T, min_value>;
using E = Max<T>;
static constexpr T op(const T& a, const T& b) { return std::max(b, a); }
};
template<class M> struct ReverseMonoid {
using value_type = typename M::value_type;
static value_type op(const value_type& a, const value_type& b) {
return M::op(b, a);
}
static value_type id() {
static_assert(has_id<M>::value, "id is not defined");
return M::id();
}
static value_type get_inv(const value_type& a) {
static_assert(has_get_inv<M>::value, "get_inv is not defined");
return M::get_inv(a);
}
};
template<class M_> struct AttachEffector {
using M = M_;
using E = M_;
using T = typename M_::value_type;
static T op(const T& a, const T& b) { return M_::op(b, a); }
};
template<class E_> struct AttachMonoid {
using M = E_;
using E = E_;
using T = typename E_::value_type;
static T op(const T& a, const T& b) { return E_::op(b, a); }
};
} // namespace Monoid
#line 6 "library/graph/tree/ReRooting.hpp"
template<class M, class T, class F> class ReRooting {
private:
using U = typename M::value_type;
const F& f;
int n;
const Graph<T>& G;
std::vector<U> init_data;
std::vector<std::vector<U>> dp;
std::vector<U> res;
std::vector<int> par;
void dfs1(int v, int p) {
rep (i, G[v].size()) {
const auto& e = G[v][i];
if (e.to == p) par[v] = i;
else dfs1(e.to, v);
}
rep (i, G[v].size()) {
const auto& e = G[v][i];
if (e.to == p) continue;
dp[v][par[v]] =
M::op(dp[v][par[v]],
f(dp[e.to][par[e.to]], edge<T>{e.to, v, e.cost, e.idx}));
}
if (p != -1 && G[v].size() == 1) {
dp[v][par[v]] = init_data[v];
}
}
void dfs2(int v, int p, int v_id) {
std::vector<U> memo(G[v].size());
rep (i, G[v].size()) {
const auto& e = G[v][i];
memo[i] = f(dp[e.to][e.to == p ? v_id : par[e.to]],
edge<T>{e.to, v, e.cost, e.idx});
}
dp[v][G[v].size() - 1] = M::id();
rrep (i, (int)G[v].size() - 1) {
dp[v][i] = M::op(memo[i + 1], dp[v][i + 1]);
}
U sml = M::id();
rep (i, G[v].size()) {
dp[v][i] = M::op(sml, dp[v][i]);
sml = M::op(sml, std::move(memo[i]));
}
dp[v].back() = std::move(sml);
if (G[v].size() == 1) {
dp[v][p == -1 ? 0 : par[v]] = std::move(init_data[v]);
}
rep (i, G[v].size()) {
const auto& e = G[v][i];
if (e.to != p) dfs2(e.to, v, i);
}
}
void init() {
n = G.size();
if (n == 1) {
res = std::move(init_data);
dp.assign(1, std::vector<U>{});
return;
}
dp.resize(n);
rep (i, n) dp[i].assign(G[i].size() + 1, M::id());
par.resize(n);
par[0] = G[0].size();
dfs1(0, -1);
dfs2(0, -1, -1);
res.resize(n);
rep (i, n) {
res[i] = std::move(dp[i].back());
dp[i].pop_back();
}
}
public:
ReRooting(const Graph<T>& G, const F& f)
: ReRooting(G, f, std::vector<U>(G.size(), M::id())) {}
ReRooting(const Graph<T>& G, const F& f, const std::vector<U>& ind)
: f(f), G(G), init_data(ind) {
init();
}
ReRooting(const Graph<T>& G, const F& f, std::vector<U>&& ind)
: f(f), G(G), init_data(std::move(ind)) {
init();
}
const std::vector<U>& get_res() const& { return res; }
std::vector<U> get_res() && { return std::move(res); }
const U& operator[](int v) const& { return res[v]; }
U operator[](int v) && { return std::move(res[v]); }
const std::vector<std::vector<U>>& get_dp() const& { return dp; }
std::vector<std::vector<U>> get_dp() && { return std::move(dp); }
const U& get_dp(int v, int p_idx) const& { return dp[v][p_idx]; }
U get_dp(int v, int p_idx) && { return std::move(dp[v][p_idx]); }
};
/**
* @brief ReRooting(全方位木DP)
* @docs docs/graph/tree/ReRooting.md
*/
#line 2 "library/graph/tree/DoublingLowestCommonAncestor.hpp"
#line 5 "library/graph/tree/DoublingLowestCommonAncestor.hpp"
template<class T> class DoublingLCA {
private:
int root, n, h;
Graph<T> G_;
const Graph<T>& G;
std::vector<edge<T>> par;
std::vector<int> dep;
std::vector<std::vector<int>> dbl;
void dfs_build(int v, int p) {
each_const (e : G[v]) {
if (e.to != p) {
par[e.to] = edge<T>(e.to, e.from, e.cost, e.idx);
dep[e.to] = dep[v] + 1;
dfs_build(e.to, v);
}
}
}
void init() {
n = G.size();
h = bitop::ceil_log2(n) + 1;
par.resize(n);
par[root] = edge<T>{};
dep.resize(n);
dep[root] = 0;
dfs_build(root, -1);
dbl.assign(n, std::vector<int>(h, -1));
rep (i, n) dbl[i][0] = par[i].to;
rep (i, h - 1) {
rep (j, n) dbl[j][i + 1] = dbl[j][i] == -1 ? -1 : dbl[dbl[j][i]][i];
}
}
public:
DoublingLCA(const Graph<T>& G, int r = 0) : root(r), G(G) { init(); }
DoublingLCA(Graph<T>&& G, int r = 0) : root(r), G_(std::move(G)), G(G_) {
init();
}
int depth(int v) const { return dep[v]; }
int parent(int v) const { return par[v].to; }
int kth_ancestor(int v, int k) const {
if (dep[v] < k) return -1;
rrep (i, h) {
if ((k >> i) & 1) v = dbl[v][i];
}
return v;
}
int kth_pow_of_2_ancestor(int v, int k) const {
if (k >= h) return -1;
return dbl[v][k];
}
int next_vertex(int s, int t) const {
assert(s != t);
if (dep[s] >= dep[t]) return parent(s);
int u = kth_ancestor(t, dep[t] - dep[s] - 1);
return parent(u) == s ? u : parent(s);
}
int kth_next_vertext(int s, int t, int k) const {
int l = lca(s, t);
int d = dep[s] + dep[t] - 2 * dep[l];
if (d < k) return -1;
if (dep[s] - dep[l] >= k) return kth_ancestor(s, k);
return kth_ancestor(t, d - k);
}
Edges<T> path(int s, int t) const {
Edges<T> pre, suf;
while (dep[s] > dep[t]) pre.push_back(par[s]), s = par[s].to;
while (dep[t] > dep[s]) suf.push_back(par[t]), t = par[t].to;
while (s != t) {
pre.push_back(par[s]), s = par[s].to;
suf.push_back(par[t]), t = par[t].to;
}
rrep (i, suf.size())
pre.emplace_back(suf[i].to, suf[i].from, suf[i].cost, suf[i].idx);
return pre;
}
int lca(int u, int v) const {
if (dep[u] > dep[v]) u = kth_ancestor(u, dep[u] - dep[v]);
if (dep[u] < dep[v]) v = kth_ancestor(v, dep[v] - dep[u]);
if (u == v) return u;
rrep (i, h) {
if (dbl[u][i] != dbl[v][i]) {
u = dbl[u][i];
v = dbl[v][i];
}
}
return parent(u);
}
int dist(int u, int v) const {
return dep[u] + dep[v] - 2 * dep[lca(u, v)];
}
};
/**
* @brief DoublingLowestCommonAncestor(ダブリングによるLCA)
* @docs docs/graph/tree/DoublingLowestCommonAncestor.md
*/
#line 4 "main.cpp"
using namespace std;
int main() {
int N, Q; scan >> N >> Q;
Graph<int> G(N);
rep (N - 1) {
int a, b; scan >> a >> b;
G.add_edge(a - 1, b - 1);
}
rep (i, N) sort(all(G[i]), [&](auto a, auto b) { return a.to < b.to; });
vector<vector<int>> g(N);
rep (i, N) {
for (auto e : G[i]) g[i].push_back(e.to);
}
DoublingLCA lca(G);
auto f = [&](int a, auto) { return a + 1; };
ReRooting<Monoid::Sum<int>, int, decltype(f)> RR(G, f);
rep (Q) {
int a, b; scan >> a >> b; --a; --b;
int dist = lca.dist(a, b);
if (dist % 2 == 1) {
prints(0);
continue;
}
int c = lca.kth_next_vertext(a, b, dist / 2);
int d = lca.next_vertex(c, a);
int e = lca.next_vertex(c, b);
int x = RR.get_dp(d, lower_bound(all(g[d]), c) - g[d].begin());
int y = RR.get_dp(e, lower_bound(all(g[e]), c) - g[e].begin());
int ans = N - x - y - 2;
prints(ans);
}
}