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QOJ

IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#411869#6736. Alice and Bobxiaodaiyang#AC ✓177ms394492kbC++142.0kb2024-05-15 20:57:322024-05-15 20:57:32

Judging History

你现在查看的是最新测评结果

  • [2024-05-15 20:57:32]
  • 评测
  • 测评结果:AC
  • 用时:177ms
  • 内存:394492kb
  • [2024-05-15 20:57:32]
  • 提交

answer

#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <random>
#include <climits>
#include <unordered_set>
#include <unordered_map>
#include <bitset>
#include <iomanip>
 
using namespace std;
 
#define endl '\n'
typedef long long ll;
#define int long long
typedef __int128_t int128;
typedef pair<int, int> PII;
typedef pair<PII, int> PIII;
const int INF = 0x3f3f3f3f, mod = 998244353;
mt19937 rng(time(0));
#define x first
#define y second
#define lowbit(x) ((x) & -(x))
//#define double long double
const int N = 10000010;
const int M = 10000000;
ll n, m;
ll fact[N], infact[N];

int qmi(int a, int k, int p)
{
    int res = 1;
    while(k)
    {
        if(k & 1) res = (ll)res * a % p;
        k >>= 1;
        a = (ll)a * a % p;
    }
    return res;
}

ll s[N]; //n个数的前缀积
ll sv[N]; //n个数的前缀积的逆元
ll inv[N]; //第i个数的逆元



void solve() {
    
    cin >> n;
    ll ans = 0;
    
    for (int i = 1; i <= n; i ++ ) {
        if (n - i - (i - 1) >= 0) {
            ans = (ans + fact[n - i] * infact[n - i - (i - 1)] % mod * fact[n - i] % mod) % mod;
        }
        
    }
    cout << ans << endl;
}
 
signed main()
{
    ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
//     freopen("input.txt", "r", stdin);
//      freopen("output.txt", "w", stdout);
    int t = 1;
    //cin >> t;
    
    s[0] = 1;
    for (int i = 1; i <= M; ++i) s[i] = s[i - 1] * i % mod;
    sv[M] = qmi(s[M], mod - 2, mod);
    // 当然这里也可以用 exgcd 来求逆元
    for (int i = M; i >= 1; --i) sv[i - 1] = sv[i] * i % mod;
    for (int i = 1; i <= M; ++i) inv[i] = sv[i] * s[i - 1] % mod;
    

    fact[0] = infact[0] = 1;
    for (int i = 1; i <= M; i ++ )
    {
        fact[i] = (ll)i * fact[i - 1] % mod;
        infact[i] = (ll)infact[i - 1] * inv[i] % mod;
    }
    while(t--)
    {
        solve();
    }
      
    return 0;
}

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100
Accepted
time: 148ms
memory: 394236kb

input:

1

output:

1

result:

ok 1 number(s): "1"

Test #2:

score: 0
Accepted
time: 171ms
memory: 394360kb

input:

2

output:

1

result:

ok 1 number(s): "1"

Test #3:

score: 0
Accepted
time: 142ms
memory: 394440kb

input:

10

output:

997920

result:

ok 1 number(s): "997920"

Test #4:

score: 0
Accepted
time: 126ms
memory: 394440kb

input:

100

output:

188898954

result:

ok 1 number(s): "188898954"

Test #5:

score: 0
Accepted
time: 157ms
memory: 394296kb

input:

4

output:

10

result:

ok 1 number(s): "10"

Test #6:

score: 0
Accepted
time: 143ms
memory: 394252kb

input:

8

output:

12336

result:

ok 1 number(s): "12336"

Test #7:

score: 0
Accepted
time: 149ms
memory: 394420kb

input:

16

output:

373118483

result:

ok 1 number(s): "373118483"

Test #8:

score: 0
Accepted
time: 157ms
memory: 394300kb

input:

32

output:

314585464

result:

ok 1 number(s): "314585464"

Test #9:

score: 0
Accepted
time: 131ms
memory: 394416kb

input:

64

output:

627827331

result:

ok 1 number(s): "627827331"

Test #10:

score: 0
Accepted
time: 135ms
memory: 394300kb

input:

128

output:

828497685

result:

ok 1 number(s): "828497685"

Test #11:

score: 0
Accepted
time: 124ms
memory: 394364kb

input:

256

output:

65697890

result:

ok 1 number(s): "65697890"

Test #12:

score: 0
Accepted
time: 135ms
memory: 394436kb

input:

512

output:

854187619

result:

ok 1 number(s): "854187619"

Test #13:

score: 0
Accepted
time: 125ms
memory: 394436kb

input:

1024

output:

513823539

result:

ok 1 number(s): "513823539"

Test #14:

score: 0
Accepted
time: 138ms
memory: 394360kb

input:

1361956

output:

617368199

result:

ok 1 number(s): "617368199"

Test #15:

score: 0
Accepted
time: 158ms
memory: 394300kb

input:

7579013

output:

827172636

result:

ok 1 number(s): "827172636"

Test #16:

score: 0
Accepted
time: 172ms
memory: 394436kb

input:

8145517

output:

710624331

result:

ok 1 number(s): "710624331"

Test #17:

score: 0
Accepted
time: 152ms
memory: 394300kb

input:

6140463

output:

707600568

result:

ok 1 number(s): "707600568"

Test #18:

score: 0
Accepted
time: 135ms
memory: 394492kb

input:

3515281

output:

698302413

result:

ok 1 number(s): "698302413"

Test #19:

score: 0
Accepted
time: 149ms
memory: 394492kb

input:

6969586

output:

69470392

result:

ok 1 number(s): "69470392"

Test #20:

score: 0
Accepted
time: 144ms
memory: 394296kb

input:

2888636

output:

433579983

result:

ok 1 number(s): "433579983"

Test #21:

score: 0
Accepted
time: 160ms
memory: 394388kb

input:

9999998

output:

758172780

result:

ok 1 number(s): "758172780"

Test #22:

score: 0
Accepted
time: 177ms
memory: 394348kb

input:

9999999

output:

605195495

result:

ok 1 number(s): "605195495"

Test #23:

score: 0
Accepted
time: 156ms
memory: 394304kb

input:

10000000

output:

866813682

result:

ok 1 number(s): "866813682"