QOJ.ac

QOJ

ID题目提交者结果用时内存语言文件大小提交时间测评时间
#409232#6736. Alice and BobyerkindarWA 1ms7784kbC++14995b2024-05-11 20:43:372024-05-11 20:43:37

Judging History

你现在查看的是最新测评结果

  • [2024-05-11 20:43:37]
  • 评测
  • 测评结果:WA
  • 用时:1ms
  • 内存:7784kb
  • [2024-05-11 20:43:37]
  • 提交

answer

#include<bits/stdc++.h>
using namespace std;
#define int long long
typedef long long ll;
int n,m,t,k;
const int N=1e7+5,mo=998244353;
typedef pair<int,int> PII;
int frac[5000005],inv[5000005],jie[5000005]; 
const int p=998244353;
ll mi(ll x,ll y)
{
	int res=1;
	for(;y;y>>=1,x=(ll)x*x%mo)
		if(y&1) res=(ll)res*x%mo;
	return res;
}
ll C(int x,int y)
{
	if(x<y) return 0;
	return (ll)frac[x]*inv[y]%mo*inv[x-y]%mo;
}
void init()
{
	int i,j;
	frac[0]=1;
	for(i=1;i<=n;i++) frac[i]=(ll)frac[i-1]*i%mo;
	inv[n]=mi(frac[n],mo-2);
	for(i=n-1;i>=0;--i) inv[i]=(ll)inv[i+1]*(i+1)%mo;
}

void solve(){
	cin>>n;
	init();
	long long ans=0;
	for(int i=1;i<=n;i++){
		if(n-i<i-1){
			break;
		}
		ans=(ans+(ll)(C(n-i,i-1)*frac[i-1]*frac[n-i])%mo)%mo;
	}
	
	cout<<ans<<endl;
}	
signed main()
{
	ios::sync_with_stdio(false), std::cin.tie(nullptr), std::cout.tie(nullptr);
    int __=1;
    //cin>>__;
    //init();
	while(__--){
		solve();
	}
	return 0;
}

詳細信息

Test #1:

score: 100
Accepted
time: 1ms
memory: 7780kb

input:

1

output:

1

result:

ok 1 number(s): "1"

Test #2:

score: 0
Accepted
time: 1ms
memory: 7700kb

input:

2

output:

1

result:

ok 1 number(s): "1"

Test #3:

score: 0
Accepted
time: 0ms
memory: 7784kb

input:

10

output:

997920

result:

ok 1 number(s): "997920"

Test #4:

score: -100
Wrong Answer
time: 1ms
memory: 7764kb

input:

100

output:

41709352

result:

wrong answer 1st numbers differ - expected: '188898954', found: '41709352'