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IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#367847#6736. Alice and Bob1677118046#AC ✓116ms159932kbC++171010b2024-03-26 15:25:072024-03-26 15:25:07

Judging History

你现在查看的是最新测评结果

  • [2024-03-26 15:25:07]
  • 评测
  • 测评结果:AC
  • 用时:116ms
  • 内存:159932kb
  • [2024-03-26 15:25:07]
  • 提交

answer

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int nn=1e7+10;
ll dp[nn];
const ll mod=998244353;
ll pow1(ll bas,ll y){
	ll ba=1;
	while(y){
		if(y&1){
			ba*=bas;
			ba%=mod;
		}
		y/=2;
		bas*=bas;
		bas%=mod;
	}
	return ba;
}
ll ji[nn];
ll inv[nn];
ll n;
void init(){
	ji[0]=1;
	for(ll i=1;i<=n;i++){
		ji[i]=ji[i-1]*i;
		ji[i]%=mod;
	}
	inv[n]=pow1(ji[n],mod-2);
	for(ll i=n-1;i>=0;i--){
		inv[i]=inv[i+1]*(i+1);
		inv[i]%=mod;
	}
}
void solve(){
	cin>>n;
	ll ans=0;
	init();
	if(n==1){
		cout<<1<<"\n";return;
	}
	for(ll i=1;i<=(n+1)/2;i++){
		ll an1=1;
		/*
		for(ll j=1;j<=i-1;j++){
			an1*=(n-i-j+1);
		}
		for(int j=1;j<=n-i;j++){
			an1*=j;
		}
		*/
		ll pos1=n-i;
		ll pos2=n-2*i+1;
		an1 *= (ji[pos1] % mod * inv[pos2] % mod) % mod;
		an1 %= mod;
		an1*=ji[pos1];
		
		an1%=mod;
		ans+=an1;
		ans%=mod;
		
	}
	cout<<ans<<"\n";
}
int main(){
	ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
	solve();
} 

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100
Accepted
time: 1ms
memory: 5728kb

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: 5616kb

input:

10

output:

997920

result:

ok 1 number(s): "997920"

Test #4:

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

input:

100

output:

188898954

result:

ok 1 number(s): "188898954"

Test #5:

score: 0
Accepted
time: 0ms
memory: 5716kb

input:

4

output:

10

result:

ok 1 number(s): "10"

Test #6:

score: 0
Accepted
time: 0ms
memory: 5612kb

input:

8

output:

12336

result:

ok 1 number(s): "12336"

Test #7:

score: 0
Accepted
time: 1ms
memory: 5728kb

input:

16

output:

373118483

result:

ok 1 number(s): "373118483"

Test #8:

score: 0
Accepted
time: 0ms
memory: 5660kb

input:

32

output:

314585464

result:

ok 1 number(s): "314585464"

Test #9:

score: 0
Accepted
time: 1ms
memory: 5700kb

input:

64

output:

627827331

result:

ok 1 number(s): "627827331"

Test #10:

score: 0
Accepted
time: 1ms
memory: 5612kb

input:

128

output:

828497685

result:

ok 1 number(s): "828497685"

Test #11:

score: 0
Accepted
time: 1ms
memory: 5696kb

input:

256

output:

65697890

result:

ok 1 number(s): "65697890"

Test #12:

score: 0
Accepted
time: 0ms
memory: 5620kb

input:

512

output:

854187619

result:

ok 1 number(s): "854187619"

Test #13:

score: 0
Accepted
time: 1ms
memory: 5624kb

input:

1024

output:

513823539

result:

ok 1 number(s): "513823539"

Test #14:

score: 0
Accepted
time: 17ms
memory: 25696kb

input:

1361956

output:

617368199

result:

ok 1 number(s): "617368199"

Test #15:

score: 0
Accepted
time: 78ms
memory: 122488kb

input:

7579013

output:

827172636

result:

ok 1 number(s): "827172636"

Test #16:

score: 0
Accepted
time: 63ms
memory: 132624kb

input:

8145517

output:

710624331

result:

ok 1 number(s): "710624331"

Test #17:

score: 0
Accepted
time: 75ms
memory: 101116kb

input:

6140463

output:

707600568

result:

ok 1 number(s): "707600568"

Test #18:

score: 0
Accepted
time: 31ms
memory: 58884kb

input:

3515281

output:

698302413

result:

ok 1 number(s): "698302413"

Test #19:

score: 0
Accepted
time: 84ms
memory: 113296kb

input:

6969586

output:

69470392

result:

ok 1 number(s): "69470392"

Test #20:

score: 0
Accepted
time: 30ms
memory: 49040kb

input:

2888636

output:

433579983

result:

ok 1 number(s): "433579983"

Test #21:

score: 0
Accepted
time: 105ms
memory: 159860kb

input:

9999998

output:

758172780

result:

ok 1 number(s): "758172780"

Test #22:

score: 0
Accepted
time: 116ms
memory: 159896kb

input:

9999999

output:

605195495

result:

ok 1 number(s): "605195495"

Test #23:

score: 0
Accepted
time: 113ms
memory: 159932kb

input:

10000000

output:

866813682

result:

ok 1 number(s): "866813682"