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QOJ

IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#414434#6736. Alice and Bobfuyouyufeng#AC ✓151ms159900kbC++201.2kb2024-05-18 23:20:112024-05-18 23:20:12

Judging History

你现在查看的是最新测评结果

  • [2024-05-18 23:20:12]
  • 评测
  • 测评结果:AC
  • 用时:151ms
  • 内存:159900kb
  • [2024-05-18 23:20:11]
  • 提交

answer

#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
#define int long long
const int N = 1e7 + 10, mod = 998244353;
long long f[N], infact[N];
LL qmi(LL a, LL k, LL p)
{
    LL res = 1;
    while (k)
    {
        if (k & 1)
            res = res * a % p;
        a = a * a % p;
        k >>= 1;
    }
    return res;
}
inline int c(int a, int b, int p) { return f[a] * infact[b] % p * infact[a - b] % p; }
void init_ass_two(int p, int n)
{
    f[0] = infact[0] = 1;
    // N的值是a和b的最大范围
    for (int i = 1; i <= n; i++)
    {
        f[i] = i * f[i - 1] % p;
    }
    infact[n] = qmi(f[n], p - 2, p);
    for (int i = n - 1; i >= 0; i--)
    {
        infact[i] = infact[i + 1] * (i + 1) % mod;
    }
} // cout<<c(a,b,p)<<'\n';
signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n;
    cin >> n;
    init_ass_two(mod, n);

    int mid = n / 2;
    if (n % 2 == 1)
        mid++;

    int res = 0;
    for (int i = 1; i <= mid; i++)
    {
        int x = 1;
        x = (x * c(n - i, i - 1, mod)) % mod;
        x = (x * f[i - 1]) % mod;
        x = (x * f[n - i]) % mod;

        res = (res + x) % mod;
    }

    cout << res;

    return 0;
}

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100
Accepted
time: 0ms
memory: 5688kb

input:

1

output:

1

result:

ok 1 number(s): "1"

Test #2:

score: 0
Accepted
time: 1ms
memory: 5656kb

input:

2

output:

1

result:

ok 1 number(s): "1"

Test #3:

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

input:

10

output:

997920

result:

ok 1 number(s): "997920"

Test #4:

score: 0
Accepted
time: 1ms
memory: 5668kb

input:

100

output:

188898954

result:

ok 1 number(s): "188898954"

Test #5:

score: 0
Accepted
time: 1ms
memory: 5688kb

input:

4

output:

10

result:

ok 1 number(s): "10"

Test #6:

score: 0
Accepted
time: 1ms
memory: 5656kb

input:

8

output:

12336

result:

ok 1 number(s): "12336"

Test #7:

score: 0
Accepted
time: 1ms
memory: 5680kb

input:

16

output:

373118483

result:

ok 1 number(s): "373118483"

Test #8:

score: 0
Accepted
time: 1ms
memory: 5680kb

input:

32

output:

314585464

result:

ok 1 number(s): "314585464"

Test #9:

score: 0
Accepted
time: 1ms
memory: 5656kb

input:

64

output:

627827331

result:

ok 1 number(s): "627827331"

Test #10:

score: 0
Accepted
time: 1ms
memory: 5748kb

input:

128

output:

828497685

result:

ok 1 number(s): "828497685"

Test #11:

score: 0
Accepted
time: 1ms
memory: 5672kb

input:

256

output:

65697890

result:

ok 1 number(s): "65697890"

Test #12:

score: 0
Accepted
time: 1ms
memory: 5736kb

input:

512

output:

854187619

result:

ok 1 number(s): "854187619"

Test #13:

score: 0
Accepted
time: 1ms
memory: 5692kb

input:

1024

output:

513823539

result:

ok 1 number(s): "513823539"

Test #14:

score: 0
Accepted
time: 19ms
memory: 28772kb

input:

1361956

output:

617368199

result:

ok 1 number(s): "617368199"

Test #15:

score: 0
Accepted
time: 87ms
memory: 124604kb

input:

7579013

output:

827172636

result:

ok 1 number(s): "827172636"

Test #16:

score: 0
Accepted
time: 69ms
memory: 134048kb

input:

8145517

output:

710624331

result:

ok 1 number(s): "710624331"

Test #17:

score: 0
Accepted
time: 77ms
memory: 101444kb

input:

6140463

output:

707600568

result:

ok 1 number(s): "707600568"

Test #18:

score: 0
Accepted
time: 31ms
memory: 61112kb

input:

3515281

output:

698302413

result:

ok 1 number(s): "698302413"

Test #19:

score: 0
Accepted
time: 63ms
memory: 114216kb

input:

6969586

output:

69470392

result:

ok 1 number(s): "69470392"

Test #20:

score: 0
Accepted
time: 37ms
memory: 51444kb

input:

2888636

output:

433579983

result:

ok 1 number(s): "433579983"

Test #21:

score: 0
Accepted
time: 151ms
memory: 159900kb

input:

9999998

output:

758172780

result:

ok 1 number(s): "758172780"

Test #22:

score: 0
Accepted
time: 123ms
memory: 159880kb

input:

9999999

output:

605195495

result:

ok 1 number(s): "605195495"

Test #23:

score: 0
Accepted
time: 115ms
memory: 159884kb

input:

10000000

output:

866813682

result:

ok 1 number(s): "866813682"