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IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#409700#6736. Alice and Bobasoulcoming#TL 0ms0kbC++201.3kb2024-05-12 16:02:082024-05-12 16:02:09

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你现在查看的是最新测评结果

  • [2024-05-12 16:02:09]
  • 评测
  • 测评结果:TL
  • 用时:0ms
  • 内存:0kb
  • [2024-05-12 16:02:08]
  • 提交

answer

#include<bits/stdc++.h>
#define int long long
#define lowbit(x) x&(-x)
#define endl '\n'

using namespace std;

const int N=1e7+6;
const int mod=998244353;
typedef pair<int,int>PII;
int a[N],f[N],fact[N],infact[N];
int qmi(int a, int k, int p)    // 快速幂模板
{
	int res = 1;
	while (k)
	{
		if (k & 1) res =res * a % p;
		a = a * a % p;
		k >>= 1;
	}
	return res;
}
int C(int n,int m){
	if(n<0||m<0)return 0;
	if(m>n)return 0;
	return ((fact[n]%mod*infact[m])%mod*infact[n-m]%mod)%mod;
}
void init()
{
	fact[0] = infact[0] = 1;
	for (int i = 1; i <N; i ++ )
	{
		fact[i] = fact[i - 1] * i % mod;
		infact[i] = infact[i - 1] * qmi(i, mod - 2, mod) % mod;
	}
}
void solve()
{
//	int n=1;
//	while(n<=11)
//	{
//		for(int i=1;i<=n;i++)a[i]=i;
//		int ans=0;
//		do{
//			int flag=0;
//			//	for(int i=1;i<=10;i++)cout<<a[i]<<" ";cout<<endl;
//			for(int i=1;i<=a[1];i++)
//			{
//				if(a[i]<a[1])flag=1;
//			}
//			if(!flag)ans++;
//		}while(next_permutation(a+1,a+1+n));
//		cout<<ans<<endl;
//		n++;
//	}	
	int n;
	cin>>n;
	int ans=fact[n-1];
	for(int i=2;i<=n;i++)
	{
		ans=(ans+C(n-i,i-1)*fact[i-1]%mod*fact[n-i]%mod)%mod;
	}
	cout<<ans<<endl;
}
signed main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	int t=1;
	init();
//	cin>>t;
	while(t--)solve();
	return 0;
}




Details

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Test #1:

score: 0
Time Limit Exceeded

input:

1

output:

1

result: