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 |
---|---|---|---|---|---|---|---|---|---|
#352144 | #8329. Excuse | grass8cow | WA | 3ms | 3996kb | C++17 | 2.1kb | 2024-03-12 21:51:04 | 2024-03-12 21:51:04 |
Judging History
answer
#include<bits/stdc++.h>
using namespace std;
#define ll long long
int n,jc[101000],ij[101000],p2[100100],i2[100100];
const int mod=998244353,G=3,GI=(mod+1)/3,inv2=(mod+1)/2;
int qpow(int a,ll b){
int c=1;
for(;b;b>>=1){
if(b&1)c=1ll*a*c%mod;
a=1ll*a*a%mod;
}
return c;
}
int lb[1<<20],L;
void init(int n){
L=1;while(L<=n)L<<=1;
for(int i=0;i<L;i++)lb[i]=(lb[i>>1]>>1)|((i&1)?(L>>1):0);
}
void NTT(int *a,int fl){
for(int i=0;i<L;i++)if(i<lb[i])swap(a[i],a[lb[i]]);
for(int o=1;o<L;o<<=1){
int Wn=qpow(fl?G:GI,(mod-1)/(o<<1));
for(int i=0;i<L;i+=(o<<1))for(int j=0,w=1;j<o;j++,w=1ll*w*Wn%mod){
int x=a[i+j],y=1ll*a[i+j+o]*w%mod;
a[i+j]=(x+y)%mod,a[i+j+o]=(x-y)%mod;
}
}
if(!fl){
int I=qpow(L,mod-2);
for(int i=0;i<L;i++)a[i]=1ll*a[i]*I%mod;
}
}
int fz1[1<<20];
void Inv(int *a,int *b,int n){
if(n==1){b[0]=qpow(a[0],mod-2);return;}
int N=(n+1)>>1;Inv(a,b,N);
init(2*n+5);
for(int i=0;i<L;i++)fz1[i]=0;
for(int i=0;i<n;i++)fz1[i]=a[i];
for(int i=N;i<L;i++)b[i]=0;
NTT(fz1,1),NTT(b,1);
for(int i=0;i<L;i++)fz1[i]=1ll*b[i]*(2-1ll*b[i]*fz1[i]%mod)%mod;
NTT(fz1,0);
for(int i=0;i<n;i++)b[i]=fz1[i];
}
int g[100010],f[101000],g_[101000],a[100100],P2[101000];
int main(){
scanf("%d",&n);
jc[0]=ij[0]=p2[0]=i2[0]=P2[0]=1;
for(int i=1;i<=n+1;i++)jc[i]=1ll*i*jc[i-1]%mod,ij[i]=qpow(jc[i],mod-2),p2[i]=2*p2[i-1]%mod,i2[i]=1ll*inv2*i2[i-1]%mod,
P2[i]=1ll*P2[i-1]*p2[i]%mod;
for(int i=0;i<=n;i++)f[i]=ij[i+1];
//g(x)=f(x/2)g(x/2)
//g_i=2^_{-i}*sum f_ig_{x-i}
g[0]=1;
for(int i=1;i<=n;i++){
for(int j=1;j<=i;j++)(g[i]+=1ll*g[i-j]*f[j]%mod)%=mod;
g[i]=1ll*g[i]*i2[i]%mod*qpow(1-i2[i],mod-2)%mod;
}
Inv(g,g_,n+1);
init(n*2+3);for(int i=n+1;i<L;i++)g_[i]=0;
for(int i=0;i<=n;i++)fz1[i]=ij[i];
NTT(g_,1),NTT(fz1,1);for(int i=0;i<L;i++)g_[i]=1ll*g_[i]*fz1[i]%mod;
NTT(g_,0);
for(int i=0;i<=n;i++)g_[i]=1ll*g_[i]*P2[i]%mod;
for(int i=0,s=0;i<=n;i++)a[i]=1ll*s*qpow(P2[i],mod-2)%mod,(s+=g_[i])%=mod;
int ans=0;
for(int i=0;i<=n;i++)(ans+=1ll*a[i]*g[n-i]%mod)%=mod;
return printf("%d",(1ll*ans*jc[n]%mod+mod)%mod),0;
}
詳細信息
Test #1:
score: 100
Accepted
time: 0ms
memory: 3864kb
input:
1
output:
499122177
result:
ok 1 number(s): "499122177"
Test #2:
score: 0
Accepted
time: 1ms
memory: 3980kb
input:
3
output:
561512450
result:
ok 1 number(s): "561512450"
Test #3:
score: 0
Accepted
time: 0ms
memory: 3944kb
input:
10
output:
609769250
result:
ok 1 number(s): "609769250"
Test #4:
score: -100
Wrong Answer
time: 3ms
memory: 3996kb
input:
1000
output:
10832169
result:
wrong answer 1st numbers differ - expected: '475714976', found: '10832169'