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IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#185120#6736. Alice and BobAyouziAC ✓106ms81724kbC++142.3kb2023-09-21 17:24:442023-09-21 17:24:44

Judging History

你现在查看的是最新测评结果

  • [2023-09-21 17:24:44]
  • 评测
  • 测评结果:AC
  • 用时:106ms
  • 内存:81724kb
  • [2023-09-21 17:24:44]
  • 提交

answer

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int N = 1e7 + 10, Mod = 998244353;

int Norm(int x) {
    if (x < 0) x += Mod;
    if (x >= Mod) x -= Mod;
    return x;
}
template<class T>
T qmi(T a, ll b) {
    T res = 1;
    while (b) {
        if (b & 1) res *= a;
        b >>= 1;
        a *= a;
    }
    return res;
}
struct Z {
    int x;
    Z(int x = 0) : x(Norm(x)) {}
    Z(ll x) : x(Norm(x % Mod)) {}
    int val() const {
        return x;
    }
    Z operator-() const {
         return Z(Norm(Mod - x));
    }
    Z inv() const {
        assert(x != 0);
        return qmi(*this, Mod - 2);
    }
    Z &operator*=(const Z &rhs) {
        x = ll(x) * rhs.x % Mod;
        return *this;
    }
    Z &operator+=(const Z &rhs) {
        x = Norm(x + rhs.x);
        return *this;
    }
    Z &operator-=(const Z &rhs) {
        x = Norm(x - rhs.x);
        return *this;
    }
    Z &operator/=(const Z &rhs) {
        return *this *= rhs.inv();
    }
    friend Z operator*(const Z &lhs, const Z &rhs) {
        Z res = lhs;
        res *= rhs;
        return res;
    }
    friend Z operator+(const Z &lhs, const Z &rhs) {
        Z res = lhs;
        res += rhs;
        return res;
    }
    friend Z operator-(const Z &lhs, const Z &rhs) {
        Z res = lhs;
        res -= rhs;
        return res;
    }
    friend Z operator/(const Z &lhs, const Z &rhs) {
        Z res = lhs;
        res /= rhs;
        return res;
    }
    friend std::istream &operator>>(std::istream &is, Z &a) {
        ll v;
        is >> v;
        a = Z(v);
        return is;
    }
    friend std::ostream &operator<<(std::ostream &os, const Z &a) {
        return os << a.val();
    }
};
Z fact[N], infact[N];

void init() {
    fact[0] = 1;
    for (int i = 1; i < N; i ++ ) {
        fact[i] = fact[i - 1] * i;
    }
    infact[N - 1] = 1 / fact[N - 1];
    for (int i = N - 1; i; i -- ) {
        infact[i - 1] = infact[i] * i;
    }
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    init();
    int n;
    cin >> n;
    Z ans = 0;
    for (int i = 1; n - i >= i - 1; i ++ ) {
        ans += fact[n - i] * fact[n - i] * infact[n - i - (i - 1)];
    }
    cout << ans << '\n';
    return 0;
}

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100
Accepted
time: 88ms
memory: 81564kb

input:

1

output:

1

result:

ok 1 number(s): "1"

Test #2:

score: 0
Accepted
time: 87ms
memory: 81644kb

input:

2

output:

1

result:

ok 1 number(s): "1"

Test #3:

score: 0
Accepted
time: 87ms
memory: 81724kb

input:

10

output:

997920

result:

ok 1 number(s): "997920"

Test #4:

score: 0
Accepted
time: 83ms
memory: 81496kb

input:

100

output:

188898954

result:

ok 1 number(s): "188898954"

Test #5:

score: 0
Accepted
time: 83ms
memory: 81580kb

input:

4

output:

10

result:

ok 1 number(s): "10"

Test #6:

score: 0
Accepted
time: 79ms
memory: 81556kb

input:

8

output:

12336

result:

ok 1 number(s): "12336"

Test #7:

score: 0
Accepted
time: 83ms
memory: 81684kb

input:

16

output:

373118483

result:

ok 1 number(s): "373118483"

Test #8:

score: 0
Accepted
time: 87ms
memory: 81508kb

input:

32

output:

314585464

result:

ok 1 number(s): "314585464"

Test #9:

score: 0
Accepted
time: 80ms
memory: 81560kb

input:

64

output:

627827331

result:

ok 1 number(s): "627827331"

Test #10:

score: 0
Accepted
time: 82ms
memory: 81548kb

input:

128

output:

828497685

result:

ok 1 number(s): "828497685"

Test #11:

score: 0
Accepted
time: 83ms
memory: 81556kb

input:

256

output:

65697890

result:

ok 1 number(s): "65697890"

Test #12:

score: 0
Accepted
time: 91ms
memory: 81556kb

input:

512

output:

854187619

result:

ok 1 number(s): "854187619"

Test #13:

score: 0
Accepted
time: 87ms
memory: 81552kb

input:

1024

output:

513823539

result:

ok 1 number(s): "513823539"

Test #14:

score: 0
Accepted
time: 90ms
memory: 81560kb

input:

1361956

output:

617368199

result:

ok 1 number(s): "617368199"

Test #15:

score: 0
Accepted
time: 106ms
memory: 81664kb

input:

7579013

output:

827172636

result:

ok 1 number(s): "827172636"

Test #16:

score: 0
Accepted
time: 95ms
memory: 81664kb

input:

8145517

output:

710624331

result:

ok 1 number(s): "710624331"

Test #17:

score: 0
Accepted
time: 96ms
memory: 81552kb

input:

6140463

output:

707600568

result:

ok 1 number(s): "707600568"

Test #18:

score: 0
Accepted
time: 91ms
memory: 81680kb

input:

3515281

output:

698302413

result:

ok 1 number(s): "698302413"

Test #19:

score: 0
Accepted
time: 95ms
memory: 81664kb

input:

6969586

output:

69470392

result:

ok 1 number(s): "69470392"

Test #20:

score: 0
Accepted
time: 95ms
memory: 81496kb

input:

2888636

output:

433579983

result:

ok 1 number(s): "433579983"

Test #21:

score: 0
Accepted
time: 102ms
memory: 81568kb

input:

9999998

output:

758172780

result:

ok 1 number(s): "758172780"

Test #22:

score: 0
Accepted
time: 106ms
memory: 81496kb

input:

9999999

output:

605195495

result:

ok 1 number(s): "605195495"

Test #23:

score: 0
Accepted
time: 99ms
memory: 81564kb

input:

10000000

output:

866813682

result:

ok 1 number(s): "866813682"