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ID题目提交者结果用时内存语言文件大小提交时间测评时间
#507706#6417. Classical Summation ProblemPoetryAC ✓147ms26628kbC++233.6kb2024-08-06 20:22:472024-08-06 20:22:48

Judging History

你现在查看的是最新测评结果

  • [2024-08-06 20:22:48]
  • 评测
  • 测评结果:AC
  • 用时:147ms
  • 内存:26628kb
  • [2024-08-06 20:22:47]
  • 提交

answer

#include <bits/stdc++.h>
using namespace std;
using i64 = long long;
template<class T>
T power(T a, i64 b) {
    T res = 1;
    for (; b; b >>= 1, a *= a) {
        if (b & 1)
            res *= a;
    }
    return res;
}
template<const i64 P>
class ModInt {
public:
    i64 x;
    static i64 Mod;

    ModInt() : x{0} {}
    ModInt(int _x) : x{(_x % getMod() + getMod()) % getMod()} {}
    ModInt(i64 _x) : x{(_x % getMod() + getMod()) % getMod()} {}

    static void setMod(i64 Mod_) {
        Mod = Mod_;
    }
    static i64 getMod() {
        return !P ? Mod : P;
    }
    explicit constexpr operator int() const {
        return x;
    }

    ModInt &operator += (ModInt a) & {
        x = x + a.x >= getMod() ? x + a.x - getMod() : x + a.x;
        return (*this);
    }
    ModInt &operator -= (ModInt a) & {
        x = x - a.x < 0 ? x - a.x + getMod() : x - a.x;
        return (*this);
    }
    ModInt &operator *= (ModInt a) & {
        (x *= a.x) %= getMod();
        return (*this);
    }
    constexpr ModInt inv() {
        return power((*this), getMod() - 2);
    }
    ModInt &operator /= (ModInt a) & {
        return (*this) *= a.inv();
    }
    friend ModInt operator + (ModInt lhs, ModInt rhs) {
        return lhs += rhs;
    }
    friend ModInt operator - (ModInt lhs, ModInt rhs) {
        return lhs -= rhs;
    }
    friend ModInt operator * (ModInt lhs, ModInt rhs) {
        return lhs *= rhs;
    }
    friend ModInt operator / (ModInt lhs, ModInt rhs) {
        return lhs /= rhs;
    }

    friend std::istream &operator >> (std::istream &is, ModInt &p) {
        return is >> p.x;
    }
    friend std::ostream &operator << (std::ostream &os, ModInt p) {
        return os << p.x;
    }
    int operator !() {
        return !x;
    }
    friend bool operator == (ModInt lhs, ModInt rhs) {
        return lhs.x == rhs.x;
    }
    friend bool operator != (ModInt lhs, ModInt rhs) {
        return lhs.x != rhs.x;
    }
    ModInt operator -() {
        return ModInt(getMod() - x);
    }
    ModInt &operator ++() & {
        ++x;
        return *this;
    }
    ModInt operator ++(int) {
        ModInt temp = *this;
        ++*this;
        return temp;
    }
} ;
template<>
i64 ModInt<0>::Mod = 1E9 + 7;
constexpr int P = 998244353, g = 3;
using Z = ModInt<P>;
struct Comb {
    int n;
    vector<Z> _fac;
    vector<Z> _invfac;
    vector<Z> _inv;
    Comb() : n{0}, _fac{1}, _invfac{1}, _inv{0} {}
    Comb(int n) : Comb() {init(n);}
    void init(int m) {
        m = min<int>(m, Z::getMod() - 1);
        if (m <= n) return;
        _fac.resize(m + 1);
        _invfac.resize(m + 1);
        _inv.resize(m + 1);
        for (int i = n + 1; i <= m; i++) _fac[i] = _fac[i - 1] * i;
        _invfac[m] = _fac[m].inv();
        for (int i = m; i > n; i--) {
            _invfac[i - 1] = _invfac[i] * i;
            _inv[i] = _invfac[i] * _fac[i - 1];
        } n = m;
    }
    Z fac(int m) {if (m > n) init(2 * m); return _fac[m];}
    Z invfac(int m) {if (m > n) init(2 * m); return _invfac[m];}
    Z inv(int m) {if (m > n) init(2 * m); return _inv[m];}
    Z binom(int n, int m) {return n < m || m < 0 ? 0 : fac(n) * invfac(m) * invfac(n - m);}
} comb;
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int n, k;
    cin >> n >> k;
    Z ans = Z(n + 1) * power(Z(n), k);
    if (k & 1 ^ 1) {
        for (int i = 1; i < n; ++i) {
            ans -= power(Z(i), k / 2) * power(Z(n - i), k / 2) * comb.binom(k, k / 2);
        }
    }
    cout << ans / 2 << '\n';
}

詳細信息

Test #1:

score: 100
Accepted
time: 0ms
memory: 3480kb

input:

3 2

output:

14

result:

ok 1 number(s): "14"

Test #2:

score: 0
Accepted
time: 0ms
memory: 3608kb

input:

5 3

output:

375

result:

ok 1 number(s): "375"

Test #3:

score: 0
Accepted
time: 0ms
memory: 3612kb

input:

2 2

output:

5

result:

ok 1 number(s): "5"

Test #4:

score: 0
Accepted
time: 0ms
memory: 3616kb

input:

10 9

output:

508778235

result:

ok 1 number(s): "508778235"

Test #5:

score: 0
Accepted
time: 0ms
memory: 3540kb

input:

69 3

output:

11497815

result:

ok 1 number(s): "11497815"

Test #6:

score: 0
Accepted
time: 0ms
memory: 3552kb

input:

994 515

output:

33689623

result:

ok 1 number(s): "33689623"

Test #7:

score: 0
Accepted
time: 1ms
memory: 3940kb

input:

4476 6182

output:

114894183

result:

ok 1 number(s): "114894183"

Test #8:

score: 0
Accepted
time: 0ms
memory: 3816kb

input:

58957 12755

output:

932388891

result:

ok 1 number(s): "932388891"

Test #9:

score: 0
Accepted
time: 22ms
memory: 3884kb

input:

218138 28238

output:

392861201

result:

ok 1 number(s): "392861201"

Test #10:

score: 0
Accepted
time: 79ms
memory: 10496kb

input:

644125 316810

output:

420621854

result:

ok 1 number(s): "420621854"

Test #11:

score: 0
Accepted
time: 82ms
memory: 14996kb

input:

612914 505428

output:

973686286

result:

ok 1 number(s): "973686286"

Test #12:

score: 0
Accepted
time: 0ms
memory: 3812kb

input:

998216 938963

output:

251335926

result:

ok 1 number(s): "251335926"

Test #13:

score: 0
Accepted
time: 0ms
memory: 3824kb

input:

990516 996933

output:

549551960

result:

ok 1 number(s): "549551960"

Test #14:

score: 0
Accepted
time: 143ms
memory: 26468kb

input:

999019 999012

output:

637189128

result:

ok 1 number(s): "637189128"

Test #15:

score: 0
Accepted
time: 144ms
memory: 26628kb

input:

999928 999950

output:

185229465

result:

ok 1 number(s): "185229465"

Test #16:

score: 0
Accepted
time: 0ms
memory: 3584kb

input:

999999 999999

output:

384164916

result:

ok 1 number(s): "384164916"

Test #17:

score: 0
Accepted
time: 141ms
memory: 26444kb

input:

999999 1000000

output:

696165930

result:

ok 1 number(s): "696165930"

Test #18:

score: 0
Accepted
time: 0ms
memory: 3828kb

input:

1000000 999999

output:

219071706

result:

ok 1 number(s): "219071706"

Test #19:

score: 0
Accepted
time: 141ms
memory: 26508kb

input:

1000000 1000000

output:

128206597

result:

ok 1 number(s): "128206597"

Test #20:

score: 0
Accepted
time: 0ms
memory: 3584kb

input:

2 10

output:

1410

result:

ok 1 number(s): "1410"

Test #21:

score: 0
Accepted
time: 0ms
memory: 3824kb

input:

84 16

output:

297627153

result:

ok 1 number(s): "297627153"

Test #22:

score: 0
Accepted
time: 0ms
memory: 3768kb

input:

643 800

output:

489237163

result:

ok 1 number(s): "489237163"

Test #23:

score: 0
Accepted
time: 1ms
memory: 3844kb

input:

9903 880

output:

595167333

result:

ok 1 number(s): "595167333"

Test #24:

score: 0
Accepted
time: 12ms
memory: 5196kb

input:

97446 89750

output:

410205549

result:

ok 1 number(s): "410205549"

Test #25:

score: 0
Accepted
time: 30ms
memory: 18312kb

input:

186460 646474

output:

32638530

result:

ok 1 number(s): "32638530"

Test #26:

score: 0
Accepted
time: 62ms
memory: 8828kb

input:

508940 244684

output:

598321755

result:

ok 1 number(s): "598321755"

Test #27:

score: 0
Accepted
time: 72ms
memory: 16208kb

input:

583646 557758

output:

858695621

result:

ok 1 number(s): "858695621"

Test #28:

score: 0
Accepted
time: 137ms
memory: 26424kb

input:

969610 992608

output:

256683498

result:

ok 1 number(s): "256683498"

Test #29:

score: 0
Accepted
time: 142ms
memory: 26548kb

input:

995106 996434

output:

411791999

result:

ok 1 number(s): "411791999"

Test #30:

score: 0
Accepted
time: 133ms
memory: 26452kb

input:

999961 999872

output:

61222370

result:

ok 1 number(s): "61222370"

Test #31:

score: 0
Accepted
time: 147ms
memory: 26488kb

input:

999977 999908

output:

831096762

result:

ok 1 number(s): "831096762"

Test #32:

score: 0
Accepted
time: 141ms
memory: 26580kb

input:

999992 999998

output:

562977678

result:

ok 1 number(s): "562977678"

Test #33:

score: 0
Accepted
time: 14ms
memory: 3784kb

input:

1000000 2

output:

118436113

result:

ok 1 number(s): "118436113"

Test #34:

score: 0
Accepted
time: 11ms
memory: 26444kb

input:

2 1000000

output:

298823641

result:

ok 1 number(s): "298823641"