QOJ.ac

QOJ

IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#790953#6736. Alice and BobHJR#AC ✓204ms238072kbC++171.3kb2024-11-28 16:10:592024-11-28 16:11:00

Judging History

你现在查看的是最新测评结果

  • [2024-11-28 16:11:00]
  • 评测
  • 测评结果:AC
  • 用时:204ms
  • 内存:238072kb
  • [2024-11-28 16:10:59]
  • 提交

answer

#include<bits/stdc++.h>
using namespace std;
#define endl "\n"
#define debug(x) cout<<#x<<": "<<x<<endl
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
using ll=long long;
using ull=unsigned long long;
const int mo=998244353;
const int N=1e7+10;
#define int long long
int ksm(int a,int b,int p){
    int res=1;
    while(b){
        if(b&2)
            res=res*a%p;
        a=a*a%p;
        b>>=1;
    }
    return res;
}
int fac[N],infac[N],inv[N];
void init(int n){
    fac[0]=1;
    for(int i=1;i<=n;i++){
        fac[i]=fac[i-1]*i%mo;
    }
    inv[0]=0;
    inv[1]=1;
    for(int i=2;i<=n;i++){
        inv[i]=mo-(mo/i*inv[mo%i]%mo)%mo;
    }
    infac[0]=1;
    for(int i=1;i<=n;i++){
        infac[i]=infac[i-1]*inv[i]%mo;
    }
}
int C(int a,int b){
    if(a<b)
        return 0;
    return fac[a]*infac[b]%mo*infac[a-b]%mo;
}
void solve(){
    int n;
    cin>>n;
    init(n);
    int ans=0;
    for(int i=1;i<=n;i++){
        // debug(C(i,i));
        ans+=C(n-i,i-1)*fac[i-1]%mo*fac[n-i]%mo;
        ans%=mo;
    }
    cout<<ans<<endl;
}
signed main(){
    ios::sync_with_stdio(0);
    cout.tie(0);
    cin.tie(0);
    int t=1;
    while(t--){
        solve();
    }
}
/*
贡献法
正难则反
数小状压
关系连边
拆位
广义单调性
最长转最短
*/

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100
Accepted
time: 1ms
memory: 7812kb

input:

1

output:

1

result:

ok 1 number(s): "1"

Test #2:

score: 0
Accepted
time: 1ms
memory: 7660kb

input:

2

output:

1

result:

ok 1 number(s): "1"

Test #3:

score: 0
Accepted
time: 1ms
memory: 7712kb

input:

10

output:

997920

result:

ok 1 number(s): "997920"

Test #4:

score: 0
Accepted
time: 1ms
memory: 7676kb

input:

100

output:

188898954

result:

ok 1 number(s): "188898954"

Test #5:

score: 0
Accepted
time: 1ms
memory: 7720kb

input:

4

output:

10

result:

ok 1 number(s): "10"

Test #6:

score: 0
Accepted
time: 1ms
memory: 7684kb

input:

8

output:

12336

result:

ok 1 number(s): "12336"

Test #7:

score: 0
Accepted
time: 1ms
memory: 7712kb

input:

16

output:

373118483

result:

ok 1 number(s): "373118483"

Test #8:

score: 0
Accepted
time: 1ms
memory: 7656kb

input:

32

output:

314585464

result:

ok 1 number(s): "314585464"

Test #9:

score: 0
Accepted
time: 0ms
memory: 7680kb

input:

64

output:

627827331

result:

ok 1 number(s): "627827331"

Test #10:

score: 0
Accepted
time: 0ms
memory: 7716kb

input:

128

output:

828497685

result:

ok 1 number(s): "828497685"

Test #11:

score: 0
Accepted
time: 0ms
memory: 7680kb

input:

256

output:

65697890

result:

ok 1 number(s): "65697890"

Test #12:

score: 0
Accepted
time: 1ms
memory: 7816kb

input:

512

output:

854187619

result:

ok 1 number(s): "854187619"

Test #13:

score: 0
Accepted
time: 0ms
memory: 7724kb

input:

1024

output:

513823539

result:

ok 1 number(s): "513823539"

Test #14:

score: 0
Accepted
time: 23ms
memory: 39984kb

input:

1361956

output:

617368199

result:

ok 1 number(s): "617368199"

Test #15:

score: 0
Accepted
time: 150ms
memory: 186212kb

input:

7579013

output:

827172636

result:

ok 1 number(s): "827172636"

Test #16:

score: 0
Accepted
time: 173ms
memory: 199848kb

input:

8145517

output:

710624331

result:

ok 1 number(s): "710624331"

Test #17:

score: 0
Accepted
time: 120ms
memory: 155840kb

input:

6140463

output:

707600568

result:

ok 1 number(s): "707600568"

Test #18:

score: 0
Accepted
time: 61ms
memory: 89816kb

input:

3515281

output:

698302413

result:

ok 1 number(s): "698302413"

Test #19:

score: 0
Accepted
time: 141ms
memory: 169432kb

input:

6969586

output:

69470392

result:

ok 1 number(s): "69470392"

Test #20:

score: 0
Accepted
time: 54ms
memory: 77260kb

input:

2888636

output:

433579983

result:

ok 1 number(s): "433579983"

Test #21:

score: 0
Accepted
time: 178ms
memory: 238072kb

input:

9999998

output:

758172780

result:

ok 1 number(s): "758172780"

Test #22:

score: 0
Accepted
time: 200ms
memory: 237996kb

input:

9999999

output:

605195495

result:

ok 1 number(s): "605195495"

Test #23:

score: 0
Accepted
time: 204ms
memory: 238068kb

input:

10000000

output:

866813682

result:

ok 1 number(s): "866813682"