QOJ.ac

QOJ

IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#383951#6736. Alice and BobGordenGhostAC ✓142ms159968kbC++171013b2024-04-09 19:10:012024-04-09 19:10:01

Judging History

你现在查看的是最新测评结果

  • [2024-04-09 19:10:01]
  • 评测
  • 测评结果:AC
  • 用时:142ms
  • 内存:159968kb
  • [2024-04-09 19:10:01]
  • 提交

answer

#include"bits/stdc++.h"
#define endl '\n'
using ll=long long;
using namespace std;
constexpr int N=10000000+5,mod=998244353;
ll fact[N],inv[N];
ll qpow(ll a,ll b,ll p){
	a%=p;
	ll ans=1%p;
	for(;b;b>>=1){
		if(b&1)
			ans=ans*a%p;
		a=a*a%p;
	}
	return ans;
}
void init(){
	fact[0]=1;
	inv[0]=1;
	for(int i=1;i<N;i++)
		fact[i]=(i*fact[i-1])%mod;
	inv[10000000]=qpow(fact[10000000],mod-2,mod);
	for(int i=10000000-1;i>=1;i--){
		inv[i]=inv[i+1]*(i+1)%mod;
	}
//	for(int i=1;i<N;i++)
//		inv[i]=qpow(fact[i],mod-2,mod);
}
ll C(ll n,ll r){
	if(r>n||r<0)
		return 0;
	if(n==r||r==0)
		return 1;
	return (fact[n]*inv[r]%mod*inv[n-r]%mod);
}
void slove(){
	init();
	int n;
	cin>>n;
	ll ans=0;
	if(n==1){
		cout<<1<<endl;
		return;
	}
	for(int i=1;i<=(n+1)/2;i++){
		ans+=C(n-i,i-1)*fact[i-1]%mod*fact[n-i]%mod;
		ans%=mod;
	}
	cout<<ans<<endl;
}
signed main(){
	cin.tie(nullptr)->sync_with_stdio(0);
	int _=1;
//	cin>>_;
	while(_--){
		slove();
	}
	return 0;
}

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100
Accepted
time: 70ms
memory: 159956kb

input:

1

output:

1

result:

ok 1 number(s): "1"

Test #2:

score: 0
Accepted
time: 63ms
memory: 159832kb

input:

2

output:

1

result:

ok 1 number(s): "1"

Test #3:

score: 0
Accepted
time: 77ms
memory: 159900kb

input:

10

output:

997920

result:

ok 1 number(s): "997920"

Test #4:

score: 0
Accepted
time: 82ms
memory: 159836kb

input:

100

output:

188898954

result:

ok 1 number(s): "188898954"

Test #5:

score: 0
Accepted
time: 86ms
memory: 159916kb

input:

4

output:

10

result:

ok 1 number(s): "10"

Test #6:

score: 0
Accepted
time: 79ms
memory: 159952kb

input:

8

output:

12336

result:

ok 1 number(s): "12336"

Test #7:

score: 0
Accepted
time: 48ms
memory: 159880kb

input:

16

output:

373118483

result:

ok 1 number(s): "373118483"

Test #8:

score: 0
Accepted
time: 99ms
memory: 159952kb

input:

32

output:

314585464

result:

ok 1 number(s): "314585464"

Test #9:

score: 0
Accepted
time: 89ms
memory: 159912kb

input:

64

output:

627827331

result:

ok 1 number(s): "627827331"

Test #10:

score: 0
Accepted
time: 90ms
memory: 159880kb

input:

128

output:

828497685

result:

ok 1 number(s): "828497685"

Test #11:

score: 0
Accepted
time: 70ms
memory: 159880kb

input:

256

output:

65697890

result:

ok 1 number(s): "65697890"

Test #12:

score: 0
Accepted
time: 55ms
memory: 159964kb

input:

512

output:

854187619

result:

ok 1 number(s): "854187619"

Test #13:

score: 0
Accepted
time: 48ms
memory: 159896kb

input:

1024

output:

513823539

result:

ok 1 number(s): "513823539"

Test #14:

score: 0
Accepted
time: 89ms
memory: 159968kb

input:

1361956

output:

617368199

result:

ok 1 number(s): "617368199"

Test #15:

score: 0
Accepted
time: 79ms
memory: 159912kb

input:

7579013

output:

827172636

result:

ok 1 number(s): "827172636"

Test #16:

score: 0
Accepted
time: 67ms
memory: 159896kb

input:

8145517

output:

710624331

result:

ok 1 number(s): "710624331"

Test #17:

score: 0
Accepted
time: 77ms
memory: 159900kb

input:

6140463

output:

707600568

result:

ok 1 number(s): "707600568"

Test #18:

score: 0
Accepted
time: 72ms
memory: 159888kb

input:

3515281

output:

698302413

result:

ok 1 number(s): "698302413"

Test #19:

score: 0
Accepted
time: 107ms
memory: 159816kb

input:

6969586

output:

69470392

result:

ok 1 number(s): "69470392"

Test #20:

score: 0
Accepted
time: 102ms
memory: 159836kb

input:

2888636

output:

433579983

result:

ok 1 number(s): "433579983"

Test #21:

score: 0
Accepted
time: 111ms
memory: 159936kb

input:

9999998

output:

758172780

result:

ok 1 number(s): "758172780"

Test #22:

score: 0
Accepted
time: 107ms
memory: 159892kb

input:

9999999

output:

605195495

result:

ok 1 number(s): "605195495"

Test #23:

score: 0
Accepted
time: 142ms
memory: 159920kb

input:

10000000

output:

866813682

result:

ok 1 number(s): "866813682"