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ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#482133 | #9121. I Love Marathon Contest | Crysfly | WA | 1ms | 5996kb | C++17 | 4.0kb | 2024-07-17 17:30:40 | 2024-07-17 17:30:41 |
Judging History
answer
// what is matter? never mind.
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
//#pragma GCC target("sse,sse2,sse3,sse4,popcnt,abm,mmx,avx,avx2")
#include<bits/stdc++.h>
#define For(i,a,b) for(int i=(a);i<=(b);++i)
#define Rep(i,a,b) for(int i=(a);i>=(b);--i)
#define ll long long
//#define int long long
#define ull unsigned long long
#define SZ(x) ((int)((x).size()))
#define ALL(x) (x).begin(),(x).end()
using namespace std;
inline int read()
{
int x;cin>>x;return x;
// char c=getchar();int x=0;bool f=0;
// for(;!isdigit(c);c=getchar())f^=!(c^45);
// for(;isdigit(c);c=getchar())x=(x<<1)+(x<<3)+(c^48);
// if(f)x=-x;return x;
}
#define mod 998244353
struct modint{
int x;
modint(int o=0){x=o;}
modint &operator = (int o){return x=o,*this;}
modint &operator +=(modint o){return x=x+o.x>=mod?x+o.x-mod:x+o.x,*this;}
modint &operator -=(modint o){return x=x-o.x<0?x-o.x+mod:x-o.x,*this;}
modint &operator *=(modint o){return x=1ll*x*o.x%mod,*this;}
modint &operator ^=(int b){
modint a=*this,c=1;
for(;b;b>>=1,a*=a)if(b&1)c*=a;
return x=c.x,*this;
}
modint &operator /=(modint o){return *this *=o^=mod-2;}
friend modint operator +(modint a,modint b){return a+=b;}
friend modint operator -(modint a,modint b){return a-=b;}
friend modint operator *(modint a,modint b){return a*=b;}
friend modint operator /(modint a,modint b){return a/=b;}
friend modint operator ^(modint a,int b){return a^=b;}
friend bool operator ==(modint a,modint b){return a.x==b.x;}
friend bool operator !=(modint a,modint b){return a.x!=b.x;}
bool operator ! () {return !x;}
modint operator - () {return x?mod-x:0;}
bool operator <(const modint&b)const{return x<b.x;}
};
inline modint qpow(modint x,int y){return x^y;}
vector<modint> fac,ifac,iv;
inline void initC(int n)
{
if(iv.empty())fac=ifac=iv=vector<modint>(2,1);
int m=iv.size(); ++n;
if(m>=n)return;
iv.resize(n),fac.resize(n),ifac.resize(n);
For(i,m,n-1){
iv[i]=iv[mod%i]*(mod-mod/i);
fac[i]=fac[i-1]*i,ifac[i]=ifac[i-1]*iv[i];
}
}
inline modint C(int n,int m){
if(m<0||n<m)return 0;
return initC(n),fac[n]*ifac[m]*ifac[n-m];
}
inline modint sign(int n){return (n&1)?(mod-1):(1);}
#define fi first
#define se second
#define pb push_back
#define mkp make_pair
typedef pair<int,int>pii;
typedef vector<int>vi;
#define maxn 200005
#define inf 0x3f3f3f3f
int n;
int b[maxn],bb[maxn];
modint res=0;
int cnt1,cnt0;
int sum[maxn];
int br(){
For(i,1,n*2)bb[i]=b[i];
int u=0,res=0,now=-1,cnt=n*2;
while(1){
if(u==n*2) u=1,++res;
else ++u;
if(cnt==0 && u==1) break;
if(b[u]==-now){
b[u]=0,now=-now;
--cnt;
}
// For(i,1,n*2)cout<<b[i]<<" "; cout<<"\n";
}
// cout<<res<<"\n";
For(i,1,n*2)b[i]=bb[i];
return res;
}
void chk(){
int mx=0,mn=0;
For(i,1,n*2){
sum[i]=sum[i-1]+b[i];
mx=max(mx,sum[i]),mn=min(mn,sum[i]);
}
// For(i,1,n*2) cout<<b[i]<<" "; cout<<"\n";
int ans=mx-mn;
{
bool ok=0;
Rep(i,n*2,0){
if(sum[i]==mn){
ok=0;
break;
}
if(sum[i]==mx){
ok=1;
break;
}
}
cnt1+=ok; cnt0+=(!ok);
ans+=ok;
}
// cout<<ans<<" "; cout<<"\n";
// int tmp=br();
// if(tmp!=ans)exit(2343);
res+=ans;
// if(mn<0)res+=1;
}
void dfs(int u,int u1,int u2){
if(u==2*n+1){
chk();
return;
}
if(u1) b[u]=1,dfs(u+1,u1-1,u2);
if(u2 && u>1) b[u]=-1,dfs(u+1,u1,u2-1);
}
modint divsum[maxn];
modint S(int n,int a){
modint res=0;
For(k,1,a+n)
res+=divsum[k]*C(n*2,n+a-k);
res/=C(n*2,n);
return res;
}
signed main()
{
n=read(); initC(n*2);
// For(i,1,n*2)
// for(int j=i;j<=n*2;j+=i) divsum[j]+=1;
modint res=0;
res+=C(2*n-1,n-1);
For(i,1,n-1) res+=C(2*n-1,n+i);
For(i,1,n-1) res+=2*C(2*n-2,n-1-i);
// modint tmp=((n+1)*S(n,1)-2*S(n,0)+S(n,-1))-1;
// tmp*=C(n*2,n)*iv[n+1];
// res-=tmp;
For(i,1,n-1) For(k,1,n) {
res+=C(2*n-2,n-k*(i+1));
res-=2*C(2*n-2,n-1-k*(i+1));
res+=C(2*n-2,n-2-k*(i+1));
}
res*=2,res*=fac[n]*fac[n];
cout<<res.x;
return 0;
}
/*
*/
Details
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Test #1:
score: 100
Accepted
time: 1ms
memory: 5996kb
input:
1
output:
2
result:
ok "2"
Test #2:
score: -100
Wrong Answer
time: 1ms
memory: 5984kb
input:
2
output:
56
result:
wrong answer 1st words differ - expected: '40', found: '56'