QOJ.ac

QOJ

IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#350650#6736. Alice and BobAlbert711RE 2ms5248kbC++201.5kb2024-03-10 22:34:382024-03-10 22:34:38

Judging History

你现在查看的是最新测评结果

  • [2024-03-10 22:34:38]
  • 评测
  • 测评结果:RE
  • 用时:2ms
  • 内存:5248kb
  • [2024-03-10 22:34:38]
  • 提交

answer

#include<bits/stdc++.h>

using namespace std;
typedef long long ll;
typedef double db;
const int N = 1e5 + 5;
const int mod = 998244353;
//#define int long long


ll fpow(ll x, ll r) {
    ll result = 1;
    while (r) {
        if (r & 1)result = result * x % mod;
        r >>= 1;
        x = x * x % mod;
    }
    return result;
}

namespace binom {
    ll fac[N], ifac[N];
    int __ = [] {
        fac[0] = 1;
        for (int i = 1; i <= N - 5; i++)
            fac[i] = fac[i - 1] * i % mod;
        ifac[N - 5] = fpow(fac[N - 5], mod - 2);
        for (int i = N - 5; i; i--)
            ifac[i - 1] = ifac[i] * i % mod;
        return 0;
    }();

    inline ll C(int n, int m) {
        if (n < m || m < 0)return 0;
        return fac[n] * ifac[m] % mod * ifac[n - m] % mod;
    }

    inline ll A(int n, int m) {
        if (n < m || m < 0)return 0;
        return fac[n] * ifac[n - m] % mod;
    }
}
using namespace binom;

void solve() {
    ll n;
    cin >> n;
    if(n==1) {
        cout<<1<<'\n';
        return;
    }
    ll ans = 0;
    ll tmp = 1;
    for (int i = 1; i <= n - 1; i++) tmp = tmp * i % mod;
    ll tt = tmp;
    for (int i = 1; i <= n; i++) {
        if (i - 1 > n - i) break;
        ans = ans + A(n - i, i - 1) * tt % mod;
        ans %= mod;
        tt = tt * fpow(n - i, mod - 2) % mod;
    }
    cout << ans << '\n';
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
//    cout << fixed << setprecision(1);
    int T = 1;
//    cin >> T;
    while (T--) solve();
    return 0;
}




Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100
Accepted
time: 2ms
memory: 5216kb

input:

1

output:

1

result:

ok 1 number(s): "1"

Test #2:

score: 0
Accepted
time: 2ms
memory: 5192kb

input:

2

output:

1

result:

ok 1 number(s): "1"

Test #3:

score: 0
Accepted
time: 2ms
memory: 5200kb

input:

10

output:

997920

result:

ok 1 number(s): "997920"

Test #4:

score: 0
Accepted
time: 2ms
memory: 5120kb

input:

100

output:

188898954

result:

ok 1 number(s): "188898954"

Test #5:

score: 0
Accepted
time: 0ms
memory: 5136kb

input:

4

output:

10

result:

ok 1 number(s): "10"

Test #6:

score: 0
Accepted
time: 2ms
memory: 5168kb

input:

8

output:

12336

result:

ok 1 number(s): "12336"

Test #7:

score: 0
Accepted
time: 1ms
memory: 5120kb

input:

16

output:

373118483

result:

ok 1 number(s): "373118483"

Test #8:

score: 0
Accepted
time: 2ms
memory: 5180kb

input:

32

output:

314585464

result:

ok 1 number(s): "314585464"

Test #9:

score: 0
Accepted
time: 0ms
memory: 5120kb

input:

64

output:

627827331

result:

ok 1 number(s): "627827331"

Test #10:

score: 0
Accepted
time: 1ms
memory: 5192kb

input:

128

output:

828497685

result:

ok 1 number(s): "828497685"

Test #11:

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

input:

256

output:

65697890

result:

ok 1 number(s): "65697890"

Test #12:

score: 0
Accepted
time: 2ms
memory: 5248kb

input:

512

output:

854187619

result:

ok 1 number(s): "854187619"

Test #13:

score: 0
Accepted
time: 2ms
memory: 5184kb

input:

1024

output:

513823539

result:

ok 1 number(s): "513823539"

Test #14:

score: -100
Runtime Error

input:

1361956

output:


result: