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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
#129386#6736. Alice and BobSeventeen_17AC ✓230ms159884kbC++171.3kb2023-07-22 17:50:072023-07-22 17:50:07

Judging History

你现在查看的是最新测评结果

  • [2023-08-10 23:21:45]
  • System Update: QOJ starts to keep a history of the judgings of all the submissions.
  • [2023-07-22 17:50:07]
  • 评测
  • 测评结果:AC
  • 用时:230ms
  • 内存:159884kb
  • [2023-07-22 17:50:07]
  • 提交

answer

#include <bits/stdc++.h>
#define endl "\n" 
#define int long long
using namespace std;

const int N = 1e7 + 10, mod = 998244353;
int f[N], vf[N]; //存储阶乘和阶乘的逆元

int ksm(int x, int y) {
    int ans = 1;
    while (y) {
        if(y & 1) ans = ans * x % mod;
        y >>= 1;
        x = x * x % mod;
    }
    return ans % mod;
} 

int inv(int x) {
    return ksm(x, mod - 2) % mod;
}

void fac()
{
    f[0] = vf[0] = 1;
    f[1] = vf[1] = 1;
    for (int i = 1; i < N; i++)
    {
        f[i] = (f[i - 1] % mod * i % mod) % mod;
    }
    for (int i = 2; i < N; i++) {
        vf[i] = (mod - mod / i) * vf[mod % i] % mod;
    } 
    for (int i = 2; i < N; i++) {
        vf[i] = vf[i - 1] * vf[i] % mod;
    } 
}

int C(int n, int m) {
    return (f[n] % mod * vf[m] % mod * vf[n - m] % mod) % mod;
}

void solve() {
    int n;
    cin >> n;
    int ans = 0;
    for (int i = 1; i <= (n + 1) / 2 ; i++) {
        ans = (ans % mod + C(n - i, i - 1) % mod * f[i - 1] % mod* f[n - i] % mod) % mod;
    }
    cout << ans << "\n";
}

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

詳細信息

Test #1:

score: 100
Accepted
time: 191ms
memory: 159708kb

input:

1

output:

1

result:

ok 1 number(s): "1"

Test #2:

score: 0
Accepted
time: 177ms
memory: 159736kb

input:

2

output:

1

result:

ok 1 number(s): "1"

Test #3:

score: 0
Accepted
time: 192ms
memory: 159708kb

input:

10

output:

997920

result:

ok 1 number(s): "997920"

Test #4:

score: 0
Accepted
time: 174ms
memory: 159668kb

input:

100

output:

188898954

result:

ok 1 number(s): "188898954"

Test #5:

score: 0
Accepted
time: 184ms
memory: 159780kb

input:

4

output:

10

result:

ok 1 number(s): "10"

Test #6:

score: 0
Accepted
time: 161ms
memory: 159672kb

input:

8

output:

12336

result:

ok 1 number(s): "12336"

Test #7:

score: 0
Accepted
time: 180ms
memory: 159668kb

input:

16

output:

373118483

result:

ok 1 number(s): "373118483"

Test #8:

score: 0
Accepted
time: 177ms
memory: 159676kb

input:

32

output:

314585464

result:

ok 1 number(s): "314585464"

Test #9:

score: 0
Accepted
time: 197ms
memory: 159844kb

input:

64

output:

627827331

result:

ok 1 number(s): "627827331"

Test #10:

score: 0
Accepted
time: 172ms
memory: 159876kb

input:

128

output:

828497685

result:

ok 1 number(s): "828497685"

Test #11:

score: 0
Accepted
time: 199ms
memory: 159712kb

input:

256

output:

65697890

result:

ok 1 number(s): "65697890"

Test #12:

score: 0
Accepted
time: 200ms
memory: 159736kb

input:

512

output:

854187619

result:

ok 1 number(s): "854187619"

Test #13:

score: 0
Accepted
time: 178ms
memory: 159736kb

input:

1024

output:

513823539

result:

ok 1 number(s): "513823539"

Test #14:

score: 0
Accepted
time: 172ms
memory: 159624kb

input:

1361956

output:

617368199

result:

ok 1 number(s): "617368199"

Test #15:

score: 0
Accepted
time: 200ms
memory: 159844kb

input:

7579013

output:

827172636

result:

ok 1 number(s): "827172636"

Test #16:

score: 0
Accepted
time: 230ms
memory: 159664kb

input:

8145517

output:

710624331

result:

ok 1 number(s): "710624331"

Test #17:

score: 0
Accepted
time: 197ms
memory: 159712kb

input:

6140463

output:

707600568

result:

ok 1 number(s): "707600568"

Test #18:

score: 0
Accepted
time: 193ms
memory: 159708kb

input:

3515281

output:

698302413

result:

ok 1 number(s): "698302413"

Test #19:

score: 0
Accepted
time: 212ms
memory: 159708kb

input:

6969586

output:

69470392

result:

ok 1 number(s): "69470392"

Test #20:

score: 0
Accepted
time: 206ms
memory: 159884kb

input:

2888636

output:

433579983

result:

ok 1 number(s): "433579983"

Test #21:

score: 0
Accepted
time: 216ms
memory: 159668kb

input:

9999998

output:

758172780

result:

ok 1 number(s): "758172780"

Test #22:

score: 0
Accepted
time: 208ms
memory: 159716kb

input:

9999999

output:

605195495

result:

ok 1 number(s): "605195495"

Test #23:

score: 0
Accepted
time: 228ms
memory: 159720kb

input:

10000000

output:

866813682

result:

ok 1 number(s): "866813682"