結果

問題 No.2068 Restricted Permutation
ユーザー t98slidert98slider
提出日時 2022-09-02 22:37:55
言語 C++14
(gcc 12.3.0 + boost 1.83.0)
結果
AC  
実行時間 14 ms / 2,000 ms
コード長 7,709 bytes
コンパイル時間 1,733 ms
コンパイル使用メモリ 173,100 KB
実行使用メモリ 6,820 KB
最終ジャッジ日時 2024-11-16 04:48:47
合計ジャッジ時間 2,732 ms
ジャッジサーバーID
（参考情報） 		judge1 / judge3
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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
6,820 KB
testcase_01 AC 2 ms
6,816 KB
testcase_02 AC 2 ms
6,820 KB
testcase_03 AC 2 ms
6,816 KB
testcase_04 AC 2 ms
6,816 KB
testcase_05 AC 2 ms
6,820 KB
testcase_06 AC 2 ms
6,816 KB
testcase_07 AC 2 ms
6,820 KB
testcase_08 AC 2 ms
6,820 KB
testcase_09 AC 2 ms
6,816 KB
testcase_10 AC 2 ms
6,816 KB
testcase_11 AC 2 ms
6,816 KB
testcase_12 AC 2 ms
6,820 KB
testcase_13 AC 2 ms
6,816 KB
testcase_14 AC 2 ms
6,816 KB
testcase_15 AC 2 ms
6,816 KB
testcase_16 AC 8 ms
6,816 KB
testcase_17 AC 12 ms
6,816 KB
testcase_18 AC 9 ms
6,820 KB
testcase_19 AC 12 ms
6,816 KB
testcase_20 AC 10 ms
6,820 KB
testcase_21 AC 14 ms
6,816 KB
testcase_22 AC 9 ms
6,816 KB
testcase_23 AC 12 ms
6,816 KB
testcase_24 AC 8 ms
6,816 KB
testcase_25 AC 6 ms
6,816 KB
権限があれば一括ダウンロードができます

ソースコード

diff # 

#include<bits/stdc++.h>
using namespace std;
using ll = long long;

namespace internal {constexpr long long safe_mod(long long x, long long m) {x %= m;if (x < 0) x += m;return x;}struct barrett {unsigned int _m;unsigned long long im;explicit barrett(unsigned int m) : _m(m), im((unsigned long long)(-1) / m + 1) {}unsigned int umod() const { return _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;}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);
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};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;auto tmp = s;s = t;t = tmp;tmp = m0;m0 = m1;m1 = tmp;}if (m0 < 0) m0 += b / s;return {s, m0};}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);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;n = (unsigned long long)(y_max / m);b = (unsigned long long)(y_max % m);std::swap(m, a);}return ans;}
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;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;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;}friend istream& operator>>(istream& os,mint& rhs) noexcept {long long v;rhs = mint{(os >> v, v)};return os;}friend constexpr ostream& operator << (ostream &os, const mint& rhs) noexcept {return os << rhs._v;}
    private:
    unsigned int _v;static constexpr unsigned int umod() { return m; }static constexpr bool prime = internal::is_prime<m>;
};
using mint = static_modint<1000000007>;
using mint2 = static_modint<998244353>;

//enumeration<mint> enu(200000);のように宣言する
template<class T> struct enumeration{
    int _n;
    vector<T> fact,inv;
    enumeration() : _n(1),fact(1){}
    enumeration(int n) : _n(n+1),fact(n+1),inv(n+1){
        fact[0]=1;
        for(int i=1;i<=n;i++)fact[i]=fact[i-1]*i;
        inv[n]=T(1)/fact[n];
        for(int i=n-1;i>=0;i--)inv[i]=inv[i+1]*(i+1);
    }
    T Per(int n,int k){
        if(k>n)return 0;
        return fact[n]*inv[n-k];
    }
    //n個の中からk個を選ぶ
    T C(int n,int k){
        if(n<0||k<0||k>n)return 0;
        return fact[n]*inv[n-k]*inv[k];
    }
    //n個の中から重複を許してk個を選ぶ
    T H(int n,int k){
        if(n==0&&k==0)return 1;
        if(n<=0||k<0)return 0;
        return C(n+k-1,k);
    }
};

int main(){
    int n, k, x;
    cin >> n >> k >> x;
    enumeration<mint2> enu(n + 10);
    mint2 ans;
    for(int i = n - 2; i >= k; i--){
        //左にi項
        //右にn - 1 - i 項
        //n - 1個の数字から2個選ぶ
        ans += enu.C(n - 1, 2) * enu.C(n - 3, i - 1) * enu.fact[i - 1] * enu.fact[n - 1 - i].pow(2);
    }
    //k項目で勝つ場合
    //x - 1以下の整数を使用
    ans += enu.C(n - 2, k - 1) * (x - 1) * enu.fact[k - 1] * enu.fact[n - k].pow(2);
    for(int i = k - 2; i >= 0; i--){
        ans += enu.C(n - 1, 2) * enu.C(n - 3, i) * enu.fact[i] * enu.fact[n - 1 - i] * enu.fact[n - 2 - i];
    }
    for(int i = k - 2; i >= 0; i--){
        //xで勝つ場合
        //xより大きい整数を利用 n - x 通り
        ans += enu.C(n - 2, i) * (n - x) * enu.fact[i] *  enu.fact[n - 1 - i] * enu.fact[n - 2 - i];
    }
    cout << ans << '\n';
}
0