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QOJ

IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#213442#6736. Alice and BobYFOQTL 334ms93668kbC++111.9kb2023-10-14 14:16:122023-10-14 14:16:12

Judging History

你现在查看的是最新测评结果

  • [2023-10-14 14:16:12]
  • 评测
  • 测评结果:TL
  • 用时:334ms
  • 内存:93668kb
  • [2023-10-14 14:16:12]
  • 提交

answer

#include<bits/stdc++.h>
#define ll long long

#define x first
#define y second
#define IO ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define pb(x) push_back(x)
#define endl '\n'
#define fix(x) cout << fixed << setprecision(x) ;
#pragma GCC optimize(2)

using namespace std;
typedef pair<int,int>PII;
typedef pair<double,double>PDD;
typedef pair<int,PII>PIP;
typedef pair<PII,int>PPI;
typedef vector<int>VI;
const int N =5e5+5;
const long long INF = 1e16;
int mod= 998244353;


ll a[10000001];
int kpow(int x,int n);
ll inv[10000001];
vector<int>p;
ll A(int n,int x){
//	cout<<n<<" "<<n-x<<endl;
//	cout<<a[n]<<" "<<a[n-x]<<endl;
	
	return a[n]*inv[n-x]%mod;
	//return a[n]*kpow(a[n-x],mod-2)%mod;
}
inline void Solve(){
	int n;
	cin>>n;
	memset(inv,-1,sizeof inv);
	a[0]=1;
	inv[1]=1;
	inv[0]=1;
	a[1]=1;
	for(int i=1;i<=n;i++){
		a[i]=a[i-1]*i;
		a[i]%=mod;
		inv[i]=kpow(a[i],mod-2);
	}
//	for(int i=1;i<=n;i++){
//		cout<<kpow(inv[i],mod-2)<<endl;
//	}
	ll res =0;
	for(int i=1;i<=n/2+1;++i){
		
		res+=A((n-i),i-1)*(a[n-i]);
	//	cout<<res<<endl;
		res%=mod;
	}
	cout<<res<<endl;
}
	

//1 0.75
signed main(){
//	IO
//	fix(16);

	int T=1;
//	cin>>T;
	for(int i=1;i<=T;i++){
	
	
		Solve();
	}
	return 0;
	
}

/*

*/

int lowbit(int n)
{
	return n&-n;
}

inline void read(int &x)
{
   int f=0;x=0;char c=getchar();
   while(c<'0'||c>'9')f|=c=='-',c=getchar();
   while(c>='0'&&c<='9')x=(x<<1)+(x<<3)+(c^48),c=getchar();
   x=f?-x:x;
}
inline void print(long long x)
{
    if(x<0){
        putchar('-');
        x=-x;
    }
    if(x>9) print(x/10);
    putchar(x%10+'0');
}

//ofstream out("file.txt");
//ifstream in("file.txt"); 
inline int kpow(int x,int y){
	if(y==0)return 1;
	if(x==0)return 0;
	long long res =1;
	long long p=x;
	for(int i=0;y>>i;++i){
		if((y>>i)&1){
			res*=p;
			res%=mod;
		}
		p*=p;
		p%=mod;
	}
	return res;
}

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100
Accepted
time: 0ms
memory: 83420kb

input:

1

output:

1

result:

ok 1 number(s): "1"

Test #2:

score: 0
Accepted
time: 0ms
memory: 83536kb

input:

2

output:

1

result:

ok 1 number(s): "1"

Test #3:

score: 0
Accepted
time: 4ms
memory: 81956kb

input:

10

output:

997920

result:

ok 1 number(s): "997920"

Test #4:

score: 0
Accepted
time: 0ms
memory: 83580kb

input:

100

output:

188898954

result:

ok 1 number(s): "188898954"

Test #5:

score: 0
Accepted
time: 0ms
memory: 81852kb

input:

4

output:

10

result:

ok 1 number(s): "10"

Test #6:

score: 0
Accepted
time: 0ms
memory: 82372kb

input:

8

output:

12336

result:

ok 1 number(s): "12336"

Test #7:

score: 0
Accepted
time: 3ms
memory: 83108kb

input:

16

output:

373118483

result:

ok 1 number(s): "373118483"

Test #8:

score: 0
Accepted
time: 3ms
memory: 82584kb

input:

32

output:

314585464

result:

ok 1 number(s): "314585464"

Test #9:

score: 0
Accepted
time: 3ms
memory: 82456kb

input:

64

output:

627827331

result:

ok 1 number(s): "627827331"

Test #10:

score: 0
Accepted
time: 7ms
memory: 83776kb

input:

128

output:

828497685

result:

ok 1 number(s): "828497685"

Test #11:

score: 0
Accepted
time: 8ms
memory: 82476kb

input:

256

output:

65697890

result:

ok 1 number(s): "65697890"

Test #12:

score: 0
Accepted
time: 7ms
memory: 82296kb

input:

512

output:

854187619

result:

ok 1 number(s): "854187619"

Test #13:

score: 0
Accepted
time: 3ms
memory: 83452kb

input:

1024

output:

513823539

result:

ok 1 number(s): "513823539"

Test #14:

score: 0
Accepted
time: 334ms
memory: 93668kb

input:

1361956

output:

617368199

result:

ok 1 number(s): "617368199"

Test #15:

score: -100
Time Limit Exceeded

input:

7579013

output:


result: