#898566 (C++17) No.2406 Difference of Coordinate Squared

提出ソース
結果

問題	No.2406 Difference of Coordinate Squared
ユーザー	rniya
提出日時	2023-08-04 22:24:01
言語	C++17 (gcc 12.3.0 + boost 1.83.0)
結果	AC
実行時間	218 ms / 2,000 ms
コード長	22,870 bytes
コンパイル時間	2,709 ms
コンパイル使用メモリ	221,280 KB
実行使用メモリ	18,556 KB
最終ジャッジ日時	2024-11-26 18:03:36
合計ジャッジ時間	5,123 ms
ジャッジサーバーID （参考情報）	judge4 / judge1
このコードへのチャレンジ
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テストケース

テストケース表示
入力	結果	実行時間実行使用メモリ
testcase_00	AC	2 ms 5,248 KB
testcase_01	AC	39 ms 17,792 KB
testcase_02	AC	42 ms 18,556 KB
testcase_03	AC	33 ms 17,648 KB
testcase_04	AC	91 ms 18,044 KB
testcase_05	AC	12 ms 5,248 KB
testcase_06	AC	28 ms 10,480 KB
testcase_07	AC	20 ms 10,496 KB
testcase_08	AC	6 ms 5,248 KB
testcase_09	AC	185 ms 17,996 KB
testcase_10	AC	59 ms 17,792 KB
testcase_11	AC	11 ms 5,248 KB
testcase_12	AC	11 ms 5,248 KB
testcase_13	AC	218 ms 17,844 KB
testcase_14	AC	45 ms 17,784 KB
testcase_15	AC	47 ms 17,780 KB
testcase_16	AC	54 ms 17,780 KB
testcase_17	AC	2 ms 5,248 KB
testcase_18	AC	6 ms 5,248 KB
testcase_19	AC	11 ms 5,248 KB
testcase_20	AC	66 ms 17,772 KB
testcase_21	AC	35 ms 17,656 KB
testcase_22	AC	17 ms 10,480 KB
testcase_23	AC	133 ms 17,792 KB
testcase_24	AC	30 ms 6,912 KB
testcase_25	AC	3 ms 5,248 KB
testcase_26	AC	2 ms 5,248 KB
testcase_27	AC	2 ms 5,248 KB
testcase_28	AC	2 ms 5,248 KB
testcase_29	AC	2 ms 5,248 KB
testcase_30	AC	2 ms 5,248 KB
testcase_31	AC	2 ms 5,248 KB
testcase_32	AC	2 ms 5,248 KB
testcase_33	AC	2 ms 5,248 KB
testcase_34	AC	2 ms 5,248 KB
testcase_35	AC	2 ms 5,248 KB
testcase_36	AC	2 ms 5,248 KB
testcase_37	AC	2 ms 5,248 KB
testcase_38	AC	2 ms 5,248 KB
testcase_39	AC	2 ms 5,248 KB
testcase_40	AC	2 ms 5,248 KB
testcase_41	AC	2 ms 5,248 KB
testcase_42	AC	2 ms 5,248 KB
testcase_43	AC	1 ms 5,248 KB
testcase_44	AC	2 ms 5,248 KB
testcase_45	AC	2 ms 5,248 KB
testcase_46	AC	1 ms 5,248 KB
testcase_47	AC	2 ms 5,248 KB
testcase_48	AC	1 ms 5,248 KB
testcase_49	AC	2 ms 5,248 KB
testcase_50	AC	2 ms 5,248 KB
testcase_51	AC	1 ms 5,248 KB
testcase_52	AC	1 ms 5,248 KB
testcase_53	AC	1 ms 5,248 KB
testcase_54	AC	2 ms 5,248 KB
testcase_55	AC	1 ms 5,248 KB
testcase_56	AC	2 ms 5,248 KB
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ソースコード

raw source code
#include <bits/stdc++.h>
#ifdef LOCAL
#include <debug.hpp>
#else
#define debug(...) void(0)
#endif

#include <type_traits>

#ifdef _MSC_VER
#include <intrin.h>
#endif

#ifdef _MSC_VER
#include <intrin.h>
#endif

namespace atcoder {

namespace internal {

// @param m `1 <= m`
// @return x mod m
constexpr long long safe_mod(long long x, long long m) {
    x %= m;
    if (x < 0) x += m;
    return x;
}

// Fast modular multiplication by barrett reduction
// Reference: https://en.wikipedia.org/wiki/Barrett_reduction
// NOTE: reconsider after Ice Lake
struct barrett {
    unsigned int _m;
    unsigned long long im;

    // @param m `1 <= m < 2^31`
    explicit barrett(unsigned int m) : _m(m), im((unsigned long long)(-1) / m + 1) {}

    // @return m
    unsigned int umod() const { return _m; }

    // @param a `0 <= a < m`
    // @param b `0 <= b < m`
    // @return `a * b % m`
    unsigned int mul(unsigned int a, unsigned int b) const {
        // [1] m = 1
        // a = b = im = 0, so okay

        // [2] m >= 2
        // im = ceil(2^64 / m)
        // -> im * m = 2^64 + r (0 <= r < m)
        // let z = a*b = c*m + d (0 <= c, d < m)
        // a*b * im = (c*m + d) * im = c*(im*m) + d*im = c*2^64 + c*r + d*im
        // c*r + d*im < m * m + m * im < m * m + 2^64 + m <= 2^64 + m * (m + 1) < 2^64 * 2
        // ((ab * im) >> 64) == c or c + 1
        unsigned long long z = a;
        z *= b;
#ifdef _MSC_VER
        unsigned long long x;
        _umul128(z, im, &x);
#else
        unsigned long long x =
            (unsigned long long)(((unsigned __int128)(z)*im) >> 64);
#endif
        unsigned int v = (unsigned int)(z - x * _m);
        if (_m <= v) v += _m;
        return v;
    }
};

// @param n `0 <= n`
// @param m `1 <= m`
// @return `(x ** n) % m`
constexpr long long pow_mod_constexpr(long long x, long long n, int m) {
    if (m == 1) return 0;
    unsigned int _m = (unsigned int)(m);
    unsigned long long r = 1;
    unsigned long long y = safe_mod(x, m);
    while (n) {
        if (n & 1) r = (r * y) % _m;
        y = (y * y) % _m;
        n >>= 1;
    }
    return r;
}

// Reference:
// M. Forisek and J. Jancina,
// Fast Primality Testing for Integers That Fit into a Machine Word
// @param n `0 <= n`
constexpr bool is_prime_constexpr(int n) {
    if (n <= 1) return false;
    if (n == 2 || n == 7 || n == 61) return true;
    if (n % 2 == 0) return false;
    long long d = n - 1;
    while (d % 2 == 0) d /= 2;
    constexpr long long bases[3] = {2, 7, 61};
    for (long long a : bases) {
        long long t = d;
        long long y = pow_mod_constexpr(a, t, n);
        while (t != n - 1 && y != 1 && y != n - 1) {
            y = y * y % n;
            t <<= 1;
        }
        if (y != n - 1 && t % 2 == 0) {
            return false;
        }
    }
    return true;
}
template <int n> constexpr bool is_prime = is_prime_constexpr(n);

// @param b `1 <= b`
// @return pair(g, x) s.t. g = gcd(a, b), xa = g (mod b), 0 <= x < b/g
constexpr std::pair<long long, long long> inv_gcd(long long a, long long b) {
    a = safe_mod(a, b);
    if (a == 0) return {b, 0};

    // Contracts:
    // [1] s - m0 * a = 0 (mod b)
    // [2] t - m1 * a = 0 (mod b)
    // [3] s * |m1| + t * |m0| <= b
    long long s = b, t = a;
    long long m0 = 0, m1 = 1;

    while (t) {
        long long u = s / t;
        s -= t * u;
        m0 -= m1 * u;  // |m1 * u| <= |m1| * s <= b

        // [3]:
        // (s - t * u) * |m1| + t * |m0 - m1 * u|
        // <= s * |m1| - t * u * |m1| + t * (|m0| + |m1| * u)
        // = s * |m1| + t * |m0| <= b

        auto tmp = s;
        s = t;
        t = tmp;
        tmp = m0;
        m0 = m1;
        m1 = tmp;
    }
    // by [3]: |m0| <= b/g
    // by g != b: |m0| < b/g
    if (m0 < 0) m0 += b / s;
    return {s, m0};
}

// Compile time primitive root
// @param m must be prime
// @return primitive root (and minimum in now)
constexpr int primitive_root_constexpr(int m) {
    if (m == 2) return 1;
    if (m == 167772161) return 3;
    if (m == 469762049) return 3;
    if (m == 754974721) return 11;
    if (m == 998244353) return 3;
    int divs[20] = {};
    divs[0] = 2;
    int cnt = 1;
    int x = (m - 1) / 2;
    while (x % 2 == 0) x /= 2;
    for (int i = 3; (long long)(i)*i <= x; i += 2) {
        if (x % i == 0) {
            divs[cnt++] = i;
            while (x % i == 0) {
                x /= i;
            }
        }
    }
    if (x > 1) {
        divs[cnt++] = x;
    }
    for (int g = 2;; g++) {
        bool ok = true;
        for (int i = 0; i < cnt; i++) {
            if (pow_mod_constexpr(g, (m - 1) / divs[i], m) == 1) {
                ok = false;
                break;
            }
        }
        if (ok) return g;
    }
}
template <int m> constexpr int primitive_root = primitive_root_constexpr(m);

// @param n `n < 2^32`
// @param m `1 <= m < 2^32`
// @return sum_{i=0}^{n-1} floor((ai + b) / m) (mod 2^64)
unsigned long long floor_sum_unsigned(unsigned long long n,
                                      unsigned long long m,
                                      unsigned long long a,
                                      unsigned long long b) {
    unsigned long long ans = 0;
    while (true) {
        if (a >= m) {
            ans += n * (n - 1) / 2 * (a / m);
            a %= m;
        }
        if (b >= m) {
            ans += n * (b / m);
            b %= m;
        }

        unsigned long long y_max = a * n + b;
        if (y_max < m) break;
        // y_max < m * (n + 1)
        // floor(y_max / m) <= n
        n = (unsigned long long)(y_max / m);
        b = (unsigned long long)(y_max % m);
        std::swap(m, a);
    }
    return ans;
}

}  // namespace internal

}  // namespace atcoder

namespace atcoder {

namespace internal {

#ifndef _MSC_VER
template <class T>
using is_signed_int128 =
    typename std::conditional<std::is_same<T, __int128_t>::value ||
                                  std::is_same<T, __int128>::value,
                              std::true_type,
                              std::false_type>::type;

template <class T>
using is_unsigned_int128 =
    typename std::conditional<std::is_same<T, __uint128_t>::value ||
                                  std::is_same<T, unsigned __int128>::value,
                              std::true_type,
                              std::false_type>::type;

template <class T>
using make_unsigned_int128 =
    typename std::conditional<std::is_same<T, __int128_t>::value,
                              __uint128_t,
                              unsigned __int128>;

template <class T>
using is_integral = typename std::conditional<std::is_integral<T>::value ||
                                                  is_signed_int128<T>::value ||
                                                  is_unsigned_int128<T>::value,
                                              std::true_type,
                                              std::false_type>::type;

template <class T>
using is_signed_int = typename std::conditional<(is_integral<T>::value &&
                                                 std::is_signed<T>::value) ||
                                                    is_signed_int128<T>::value,
                                                std::true_type,
                                                std::false_type>::type;

template <class T>
using is_unsigned_int =
    typename std::conditional<(is_integral<T>::value &&
                               std::is_unsigned<T>::value) ||
                                  is_unsigned_int128<T>::value,
                              std::true_type,
                              std::false_type>::type;

template <class T>
using to_unsigned = typename std::conditional<
    is_signed_int128<T>::value,
    make_unsigned_int128<T>,
    typename std::conditional<std::is_signed<T>::value,
                              std::make_unsigned<T>,
                              std::common_type<T>>::type>::type;

#else

template <class T> using is_integral = typename std::is_integral<T>;

template <class T>
using is_signed_int =
    typename std::conditional<is_integral<T>::value && std::is_signed<T>::value,
                              std::true_type,
                              std::false_type>::type;

template <class T>
using is_unsigned_int =
    typename std::conditional<is_integral<T>::value &&
                                  std::is_unsigned<T>::value,
                              std::true_type,
                              std::false_type>::type;

template <class T>
using to_unsigned = typename std::conditional<is_signed_int<T>::value,
                                              std::make_unsigned<T>,
                                              std::common_type<T>>::type;

#endif

template <class T>
using is_signed_int_t = std::enable_if_t<is_signed_int<T>::value>;

template <class T>
using is_unsigned_int_t = std::enable_if_t<is_unsigned_int<T>::value>;

template <class T> using to_unsigned_t = typename to_unsigned<T>::type;

}  // namespace internal

}  // namespace atcoder

namespace atcoder {

namespace internal {

struct modint_base {};
struct static_modint_base : modint_base {};

template <class T> using is_modint = std::is_base_of<modint_base, T>;
template <class T> using is_modint_t = std::enable_if_t<is_modint<T>::value>;

}  // namespace internal

template <int m, std::enable_if_t<(1 <= m)>* = nullptr>
struct static_modint : internal::static_modint_base {
    using mint = static_modint;

  public:
    static constexpr int mod() { return m; }
    static mint raw(int v) {
        mint x;
        x._v = v;
        return x;
    }

    static_modint() : _v(0) {}
    template <class T, internal::is_signed_int_t<T>* = nullptr>
    static_modint(T v) {
        long long x = (long long)(v % (long long)(umod()));
        if (x < 0) x += umod();
        _v = (unsigned int)(x);
    }
    template <class T, internal::is_unsigned_int_t<T>* = nullptr>
    static_modint(T v) {
        _v = (unsigned int)(v % umod());
    }

    unsigned int val() const { return _v; }

    mint& operator++() {
        _v++;
        if (_v == umod()) _v = 0;
        return *this;
    }
    mint& operator--() {
        if (_v == 0) _v = umod();
        _v--;
        return *this;
    }
    mint operator++(int) {
        mint result = *this;
        ++*this;
        return result;
    }
    mint operator--(int) {
        mint result = *this;
        --*this;
        return result;
    }

    mint& operator+=(const mint& rhs) {
        _v += rhs._v;
        if (_v >= umod()) _v -= umod();
        return *this;
    }
    mint& operator-=(const mint& rhs) {
        _v -= rhs._v;
        if (_v >= umod()) _v += umod();
        return *this;
    }
    mint& operator*=(const mint& rhs) {
        unsigned long long z = _v;
        z *= rhs._v;
        _v = (unsigned int)(z % umod());
        return *this;
    }
    mint& operator/=(const mint& rhs) { return *this = *this * rhs.inv(); }

    mint operator+() const { return *this; }
    mint operator-() const { return mint() - *this; }

    mint pow(long long n) const {
        assert(0 <= n);
        mint x = *this, r = 1;
        while (n) {
            if (n & 1) r *= x;
            x *= x;
            n >>= 1;
        }
        return r;
    }
    mint inv() const {
        if (prime) {
            assert(_v);
            return pow(umod() - 2);
        } else {
            auto eg = internal::inv_gcd(_v, m);
            assert(eg.first == 1);
            return eg.second;
        }
    }

    friend mint operator+(const mint& lhs, const mint& rhs) {
        return mint(lhs) += rhs;
    }
    friend mint operator-(const mint& lhs, const mint& rhs) {
        return mint(lhs) -= rhs;
    }
    friend mint operator*(const mint& lhs, const mint& rhs) {
        return mint(lhs) *= rhs;
    }
    friend mint operator/(const mint& lhs, const mint& rhs) {
        return mint(lhs) /= rhs;
    }
    friend bool operator==(const mint& lhs, const mint& rhs) {
        return lhs._v == rhs._v;
    }
    friend bool operator!=(const mint& lhs, const mint& rhs) {
        return lhs._v != rhs._v;
    }

  private:
    unsigned int _v;
    static constexpr unsigned int umod() { return m; }
    static constexpr bool prime = internal::is_prime<m>;
};

template <int id> struct dynamic_modint : internal::modint_base {
    using mint = dynamic_modint;

  public:
    static int mod() { return (int)(bt.umod()); }
    static void set_mod(int m) {
        assert(1 <= m);
        bt = internal::barrett(m);
    }
    static mint raw(int v) {
        mint x;
        x._v = v;
        return x;
    }

    dynamic_modint() : _v(0) {}
    template <class T, internal::is_signed_int_t<T>* = nullptr>
    dynamic_modint(T v) {
        long long x = (long long)(v % (long long)(mod()));
        if (x < 0) x += mod();
        _v = (unsigned int)(x);
    }
    template <class T, internal::is_unsigned_int_t<T>* = nullptr>
    dynamic_modint(T v) {
        _v = (unsigned int)(v % mod());
    }

    unsigned int val() const { return _v; }

    mint& operator++() {
        _v++;
        if (_v == umod()) _v = 0;
        return *this;
    }
    mint& operator--() {
        if (_v == 0) _v = umod();
        _v--;
        return *this;
    }
    mint operator++(int) {
        mint result = *this;
        ++*this;
        return result;
    }
    mint operator--(int) {
        mint result = *this;
        --*this;
        return result;
    }

    mint& operator+=(const mint& rhs) {
        _v += rhs._v;
        if (_v >= umod()) _v -= umod();
        return *this;
    }
    mint& operator-=(const mint& rhs) {
        _v += mod() - rhs._v;
        if (_v >= umod()) _v -= umod();
        return *this;
    }
    mint& operator*=(const mint& rhs) {
        _v = bt.mul(_v, rhs._v);
        return *this;
    }
    mint& operator/=(const mint& rhs) { return *this = *this * rhs.inv(); }

    mint operator+() const { return *this; }
    mint operator-() const { return mint() - *this; }

    mint pow(long long n) const {
        assert(0 <= n);
        mint x = *this, r = 1;
        while (n) {
            if (n & 1) r *= x;
            x *= x;
            n >>= 1;
        }
        return r;
    }
    mint inv() const {
        auto eg = internal::inv_gcd(_v, mod());
        assert(eg.first == 1);
        return eg.second;
    }

    friend mint operator+(const mint& lhs, const mint& rhs) {
        return mint(lhs) += rhs;
    }
    friend mint operator-(const mint& lhs, const mint& rhs) {
        return mint(lhs) -= rhs;
    }
    friend mint operator*(const mint& lhs, const mint& rhs) {
        return mint(lhs) *= rhs;
    }
    friend mint operator/(const mint& lhs, const mint& rhs) {
        return mint(lhs) /= rhs;
    }
    friend bool operator==(const mint& lhs, const mint& rhs) {
        return lhs._v == rhs._v;
    }
    friend bool operator!=(const mint& lhs, const mint& rhs) {
        return lhs._v != rhs._v;
    }

  private:
    unsigned int _v;
    static internal::barrett bt;
    static unsigned int umod() { return bt.umod(); }
};
template <int id> internal::barrett dynamic_modint<id>::bt(998244353);

using modint998244353 = static_modint<998244353>;
using modint1000000007 = static_modint<1000000007>;
using modint = dynamic_modint<-1>;

namespace internal {

template <class T>
using is_static_modint = std::is_base_of<internal::static_modint_base, T>;

template <class T>
using is_static_modint_t = std::enable_if_t<is_static_modint<T>::value>;

template <class> struct is_dynamic_modint : public std::false_type {};
template <int id>
struct is_dynamic_modint<dynamic_modint<id>> : public std::true_type {};

template <class T>
using is_dynamic_modint_t = std::enable_if_t<is_dynamic_modint<T>::value>;

}  // namespace internal

}  // namespace atcoder

template <typename T> struct Binomial {
    Binomial(int MAX = 0) : n(1), facs(1, T(1)), finvs(1, T(1)), invs(1, T(1)) {
        while (n <= MAX) extend();
    }

    T fac(int i) {
        assert(i >= 0);
        while (n <= i) extend();
        return facs[i];
    }

    T finv(int i) {
        assert(i >= 0);
        while (n <= i) extend();
        return finvs[i];
    }

    T inv(int i) {
        assert(i >= 0);
        while (n <= i) extend();
        return invs[i];
    }

    T P(int n, int r) {
        if (n < 0 || n < r || r < 0) return T(0);
        return fac(n) * finv(n - r);
    }

    T C(int n, int r) {
        if (n < 0 || n < r || r < 0) return T(0);
        return fac(n) * finv(n - r) * finv(r);
    }

    T H(int n, int r) {
        if (n < 0 || r < 0) return T(0);
        return r == 0 ? 1 : C(n + r - 1, r);
    }

    T C_naive(int n, int r) {
        if (n < 0 || n < r || r < 0) return T(0);
        T res = 1;
        r = std::min(r, n - r);
        for (int i = 1; i <= r; i++) res *= inv(i) * (n--);
        return res;
    }

  private:
    int n;
    std::vector<T> facs, finvs, invs;

    inline void extend() {
        int m = n << 1;
        facs.resize(m);
        finvs.resize(m);
        invs.resize(m);
        for (int i = n; i < m; i++) facs[i] = facs[i - 1] * i;
        finvs[m - 1] = T(1) / facs[m - 1];
        invs[m - 1] = finvs[m - 1] * facs[m - 2];
        for (int i = m - 2; i >= n; i--) {
            finvs[i] = finvs[i + 1] * (i + 1);
            invs[i] = finvs[i] * facs[i - 1];
        }
        n = m;
    }
};

namespace elementary_math {

template <typename T> std::vector<T> divisor(T n) {
    std::vector<T> res;
    for (T i = 1; i * i <= n; i++) {
        if (n % i == 0) {
            res.emplace_back(i);
            if (i * i != n) res.emplace_back(n / i);
        }
    }
    return res;
}

template <typename T> std::vector<std::pair<T, int>> prime_factor(T n) {
    std::vector<std::pair<T, int>> res;
    for (T p = 2; p * p <= n; p++) {
        if (n % p == 0) {
            res.emplace_back(p, 0);
            while (n % p == 0) {
                res.back().second++;
                n /= p;
            }
        }
    }
    if (n > 1) res.emplace_back(n, 1);
    return res;
}

std::vector<int> osa_k(int n) {
    std::vector<int> min_factor(n + 1, 0);
    for (int i = 2; i <= n; i++) {
        if (min_factor[i]) continue;
        for (int j = i; j <= n; j += i) {
            if (!min_factor[j]) {
                min_factor[j] = i;
            }
        }
    }
    return min_factor;
}

std::vector<int> prime_factor(const std::vector<int>& min_factor, int n) {
    std::vector<int> res;
    while (n > 1) {
        res.emplace_back(min_factor[n]);
        n /= min_factor[n];
    }
    return res;
}

long long modpow(long long x, long long n, long long mod) {
    assert(0 <= n && 1 <= mod && mod < (1LL << 31));
    if (mod == 1) return 0;
    x %= mod;
    long long res = 1;
    while (n > 0) {
        if (n & 1) res = res * x % mod;
        x = x * x % mod;
        n >>= 1;
    }
    return res;
}

long long extgcd(long long a, long long b, long long& x, long long& y) {
    long long d = a;
    if (b != 0) {
        d = extgcd(b, a % b, y, x);
        y -= (a / b) * x;
    } else
        x = 1, y = 0;
    return d;
}

long long inv_mod(long long a, long long mod) {
    assert(1 <= mod);
    long long x, y;
    if (extgcd(a, mod, x, y) != 1) return -1;
    return (mod + x % mod) % mod;
}

template <typename T> T euler_phi(T n) {
    auto pf = prime_factor(n);
    T res = n;
    for (const auto& p : pf) {
        res /= p.first;
        res *= p.first - 1;
    }
    return res;
}

std::vector<int> euler_phi_table(int n) {
    std::vector<int> res(n + 1, 0);
    iota(res.begin(), res.end(), 0);
    for (int i = 2; i <= n; i++) {
        if (res[i] != i) continue;
        for (int j = i; j <= n; j += i) res[j] = res[j] / i * (i - 1);
    }
    return res;
}

// minimum i > 0 s.t. x^i \equiv 1 \pmod{m}
template <typename T> T order(T x, T m) {
    T n = euler_phi(m);
    auto cand = divisor(n);
    sort(cand.begin(), cand.end());
    for (auto& i : cand) {
        if (modpow(x, i, m) == 1) {
            return i;
        }
    }
    return -1;
}

template <typename T> std::vector<std::tuple<T, T, T>> quotient_ranges(T n) {
    std::vector<std::tuple<T, T, T>> res;
    T m = 1;
    for (; m * m <= n; m++) res.emplace_back(m, m, n / m);
    for (; m >= 1; m--) {
        T l = n / (m + 1) + 1, r = n / m;
        if (l <= r and std::get<1>(res.back()) < l) res.emplace_back(l, r, n / l);
    }
    return res;
}

}  // namespace elementary_math

using namespace std;

typedef long long ll;
#define all(x) begin(x), end(x)
constexpr int INF = (1 << 30) - 1;
constexpr long long IINF = (1LL << 60) - 1;
constexpr int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};

template <class T> istream& operator>>(istream& is, vector<T>& v) {
    for (auto& x : v) is >> x;
    return is;
}

template <class T> ostream& operator<<(ostream& os, const vector<T>& v) {
    auto sep = "";
    for (const auto& x : v) os << exchange(sep, " ") << x;
    return os;
}

template <class T, class U = T> bool chmin(T& x, U&& y) { return y < x and (x = forward<U>(y), true); }

template <class T, class U = T> bool chmax(T& x, U&& y) { return x < y and (x = forward<U>(y), true); }

template <class T> void mkuni(vector<T>& v) {
    sort(begin(v), end(v));
    v.erase(unique(begin(v), end(v)), end(v));
}

template <class T> int lwb(const vector<T>& v, const T& x) { return lower_bound(begin(v), end(v), x) - begin(v); }

using mint = atcoder::modint998244353;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    Binomial<mint> BINOM;
    int N;
    ll M;
    cin >> N >> M;

    M = abs(M);
    mint ans = 0;
    if (M == 0) {
        if (N & 1) {
            cout << 0 << '\n';
            return 0;
        }
        ans += mint(2).pow(N) * BINOM.C(N, N / 2) * 2;
        // X = Y = 0
        for (int i = 0; i * 2 <= N; i++)
            ans -= BINOM.fac(N) * BINOM.finv(i) * BINOM.finv(i) * BINOM.finv(N / 2 - i) * BINOM.finv(N / 2 - i);
        ans /= mint(4).pow(N);
        cout << ans.val() << '\n';
        return 0;
    }
    auto ds = elementary_math::divisor(M);
    set<pair<ll, ll>> s;
    for (ll& d : ds) {
        ll e = M / d;
        if ((d + e) & 1) continue;
        {
            ll X = (d + e) / 2, Y = d - X;
            s.emplace(X, Y);
        }
        {
            ll X = -(d + e) / 2, Y = -d - X;
            s.emplace(X, Y);
        }
    }
    for (auto [X, Y] : s) {
        X = abs(X), Y = abs(Y);
        if (N < X + Y) continue;
        int rest = N - X - Y;
        if (rest & 1) continue;
        rest /= 2;
        for (int i = 0; i <= rest; i++)
            ans += BINOM.fac(N) * BINOM.finv(X + i) * BINOM.finv(i) * BINOM.finv(Y + (rest - i)) * BINOM.finv(rest - i);
    }

    ans /= mint(4).pow(N);
    cout << ans.val() << '\n';
    return 0;
}
yukicoder

結果

テストケース

ソースコード
