QOJ.ac
QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#413425 | #6736. Alice and Bob | SSHL# | WA | 107ms | 159956kb | C++14 | 1.1kb | 2024-05-17 15:15:07 | 2024-05-17 15:15:08 |
Judging History
answer
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
constexpr int N=1e5+1;
constexpr ll mod=998244353;
constexpr int maxn=1e7;
ll fac[maxn],inv[maxn];
ll pow(ll a,ll b)
{
ll res=1;
a%=mod;
while(b)
{
if(b&1)
res=res*a%mod;
a=a*a%mod;
b>>=1;
}
return res;
}
void pre()
{
fac[0]=1;
for(int i=1;i<maxn;i++)
{
fac[i]=fac[i-1]*i%mod;
}
inv[maxn-1]=pow(fac[maxn-1],mod-2);
for(int i=maxn-2;i>=0;i--)
{
inv[i]=inv[i+1]*(i+1)%mod;
}
}
ll c(ll a,ll b)
{
if(b>a||b<0)
return 0;
return fac[a]*inv[b]%mod*inv[a-b]%mod;
}
void solve()
{
pre();
ll n;
cin>>n;
ll ans=0;
if(n==1)
{
cout<<1;
return;
}
for(int i=1;i<=n/2;i++)
{
ans+=((c(n-i,i-1)*fac[n-i])%mod*fac[i-1])%mod;
ans%=mod;
// cout<<c(n-i,i-1)<<' '<<fac[n-i]<<'\n';
}
cout<<ans%mod;
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(nullptr);
int t = 1;
// cin >> t;
while (t--)
solve();
return 0;
}
Details
Tip: Click on the bar to expand more detailed information
Test #1:
score: 100
Accepted
time: 81ms
memory: 159948kb
input:
1
output:
1
result:
ok 1 number(s): "1"
Test #2:
score: 0
Accepted
time: 79ms
memory: 159888kb
input:
2
output:
1
result:
ok 1 number(s): "1"
Test #3:
score: 0
Accepted
time: 88ms
memory: 159888kb
input:
10
output:
997920
result:
ok 1 number(s): "997920"
Test #4:
score: 0
Accepted
time: 85ms
memory: 159940kb
input:
100
output:
188898954
result:
ok 1 number(s): "188898954"
Test #5:
score: 0
Accepted
time: 87ms
memory: 159860kb
input:
4
output:
10
result:
ok 1 number(s): "10"
Test #6:
score: 0
Accepted
time: 80ms
memory: 159940kb
input:
8
output:
12336
result:
ok 1 number(s): "12336"
Test #7:
score: 0
Accepted
time: 87ms
memory: 159816kb
input:
16
output:
373118483
result:
ok 1 number(s): "373118483"
Test #8:
score: 0
Accepted
time: 83ms
memory: 159772kb
input:
32
output:
314585464
result:
ok 1 number(s): "314585464"
Test #9:
score: 0
Accepted
time: 93ms
memory: 159856kb
input:
64
output:
627827331
result:
ok 1 number(s): "627827331"
Test #10:
score: 0
Accepted
time: 77ms
memory: 159952kb
input:
128
output:
828497685
result:
ok 1 number(s): "828497685"
Test #11:
score: 0
Accepted
time: 75ms
memory: 159956kb
input:
256
output:
65697890
result:
ok 1 number(s): "65697890"
Test #12:
score: 0
Accepted
time: 89ms
memory: 159952kb
input:
512
output:
854187619
result:
ok 1 number(s): "854187619"
Test #13:
score: 0
Accepted
time: 96ms
memory: 159884kb
input:
1024
output:
513823539
result:
ok 1 number(s): "513823539"
Test #14:
score: 0
Accepted
time: 96ms
memory: 159824kb
input:
1361956
output:
617368199
result:
ok 1 number(s): "617368199"
Test #15:
score: -100
Wrong Answer
time: 107ms
memory: 159872kb
input:
7579013
output:
693151411
result:
wrong answer 1st numbers differ - expected: '827172636', found: '693151411'