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QOJ

IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#183999#6736. Alice and Bob0x3eaAC ✓168ms159788kbC++141.5kb2023-09-20 09:47:082023-09-20 09:47:08

Judging History

你现在查看的是最新测评结果

  • [2023-09-20 09:47:08]
  • 评测
  • 测评结果:AC
  • 用时:168ms
  • 内存:159788kb
  • [2023-09-20 09:47:08]
  • 提交

answer

#pragma GCC optimize(2)
#include <bits/stdc++.h>
#define endl '\n'
#define x first
#define y second
#define stop cout << "?" << '\n'
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
const int N = 1e7 + 10, M = 7e5;
const ll mod = 998244353;
const double pi = acos(-1);
int n, m;
ll fac[N], invfac[N];
ll qmi(ll a, ll b = mod - 2)
{
    a %= mod;
    ll res = 1;
    while (b)
    {
        if (b & 1)
            res = res * a % mod;
        b >>= 1;
        a = a * a % mod;
    }
    return res;
}
void init()
{
    //   int n = 1e7+10;
    fac[0] = 1; // fac[i]表示i的阶乘,invfac[i]表示i的阶乘的逆元
    for (int i = 1; i <= n; i++)
        fac[i] = fac[i - 1] * i % mod;
    invfac[n] = qmi(fac[n]); // 快速幂
    for (int i = n - 1; i >= 0; i--)
        invfac[i] = invfac[i + 1] * (i + 1) % mod;
    // C(n,m)=fac[n] * invfac[m] % mod * invfac[n - m] % mod;
}
ll C(int n, int m)
{
    if (n < m || m < 0) // 注意判断是否合法
        return 0;
    return fac[n] * invfac[m] % mod * invfac[n - m] % mod;
}

void solve()
{
    cin >> n;
    init();
    ll ans = 0;
    for (int i = 1; i <= n; i++)
    {
        ll res = C(n - i, i - 1) * fac[n - i] % mod * fac[i - 1] % mod;
        ans = (ans + res) % mod;
        // cout << C(1, 0) << endl;
        // ans %= mod;
    }
    cout << ans << endl;
}
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int _ = 1;
    // cin >> _;
    while (_--)
        solve();
    return 0;
}

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100
Accepted
time: 1ms
memory: 5612kb

input:

1

output:

1

result:

ok 1 number(s): "1"

Test #2:

score: 0
Accepted
time: 1ms
memory: 5472kb

input:

2

output:

1

result:

ok 1 number(s): "1"

Test #3:

score: 0
Accepted
time: 1ms
memory: 5480kb

input:

10

output:

997920

result:

ok 1 number(s): "997920"

Test #4:

score: 0
Accepted
time: 0ms
memory: 5488kb

input:

100

output:

188898954

result:

ok 1 number(s): "188898954"

Test #5:

score: 0
Accepted
time: 1ms
memory: 5424kb

input:

4

output:

10

result:

ok 1 number(s): "10"

Test #6:

score: 0
Accepted
time: 1ms
memory: 5472kb

input:

8

output:

12336

result:

ok 1 number(s): "12336"

Test #7:

score: 0
Accepted
time: 0ms
memory: 5500kb

input:

16

output:

373118483

result:

ok 1 number(s): "373118483"

Test #8:

score: 0
Accepted
time: 1ms
memory: 5432kb

input:

32

output:

314585464

result:

ok 1 number(s): "314585464"

Test #9:

score: 0
Accepted
time: 1ms
memory: 5648kb

input:

64

output:

627827331

result:

ok 1 number(s): "627827331"

Test #10:

score: 0
Accepted
time: 1ms
memory: 5608kb

input:

128

output:

828497685

result:

ok 1 number(s): "828497685"

Test #11:

score: 0
Accepted
time: 1ms
memory: 5652kb

input:

256

output:

65697890

result:

ok 1 number(s): "65697890"

Test #12:

score: 0
Accepted
time: 1ms
memory: 5380kb

input:

512

output:

854187619

result:

ok 1 number(s): "854187619"

Test #13:

score: 0
Accepted
time: 1ms
memory: 5496kb

input:

1024

output:

513823539

result:

ok 1 number(s): "513823539"

Test #14:

score: 0
Accepted
time: 16ms
memory: 28668kb

input:

1361956

output:

617368199

result:

ok 1 number(s): "617368199"

Test #15:

score: 0
Accepted
time: 88ms
memory: 125260kb

input:

7579013

output:

827172636

result:

ok 1 number(s): "827172636"

Test #16:

score: 0
Accepted
time: 86ms
memory: 133440kb

input:

8145517

output:

710624331

result:

ok 1 number(s): "710624331"

Test #17:

score: 0
Accepted
time: 104ms
memory: 101656kb

input:

6140463

output:

707600568

result:

ok 1 number(s): "707600568"

Test #18:

score: 0
Accepted
time: 60ms
memory: 60664kb

input:

3515281

output:

698302413

result:

ok 1 number(s): "698302413"

Test #19:

score: 0
Accepted
time: 105ms
memory: 113644kb

input:

6969586

output:

69470392

result:

ok 1 number(s): "69470392"

Test #20:

score: 0
Accepted
time: 46ms
memory: 51248kb

input:

2888636

output:

433579983

result:

ok 1 number(s): "433579983"

Test #21:

score: 0
Accepted
time: 111ms
memory: 159700kb

input:

9999998

output:

758172780

result:

ok 1 number(s): "758172780"

Test #22:

score: 0
Accepted
time: 143ms
memory: 159672kb

input:

9999999

output:

605195495

result:

ok 1 number(s): "605195495"

Test #23:

score: 0
Accepted
time: 168ms
memory: 159788kb

input:

10000000

output:

866813682

result:

ok 1 number(s): "866813682"