QOJ.ac
QOJ
| ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
|---|---|---|---|---|---|---|---|---|---|
| #227061 | #6736. Alice and Bob | BILLION_mengyi# | AC ✓ | 654ms | 162300kb | C++20 | 994b | 2023-10-26 20:41:24 | 2023-10-26 20:41:25 |
Judging History
answer
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N=10000010,mod=998244353;
ll fact[N],infact[N],jc[N];//阶乘和阶乘的逆元
ll qmi(ll a,ll k,ll p)
{
ll res=1;
while(k)
{
if(k&1)
{
if(res>=mod) res%=mod;
res*=a;
if(res>=mod) res%=mod;
}
if(a>=mod) a%=mod;
a*=a;
if(a>=mod) a%=mod;
k>>=1;
}
return res;
}
ll C(ll a,ll b)
{
if(b>a) return 0;
return fact[a]*infact[b]%mod*infact[a-b]%mod;
}
void solve()
{
jc[1]=1;jc[0]=1;
fact[0]=infact[0]=1;
for(ll i=1;i<N-5;i++)
{
fact[i]=fact[i-1]*i%mod;
jc[i]=fact[i];
}
ll n;cin>>n;
ll ans=0;
ll mx=(n+1)/2;
for(int i=1;i<=mx;i++)
{
ll w=jc[n-i]*jc[n-i];
w%=mod;
w*=qmi(jc[n-2*i+1],mod-2,mod);
w%=mod;
ans+=w;
if(ans>=mod) ans%=mod;
}
cout<<ans<<"\n";
}
int main()
{
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
ll T=1;
while(T--)
{
solve();
}
return 0;
}
Details
Tip: Click on the bar to expand more detailed information
Test #1:
score: 100
Accepted
time: 31ms
memory: 162168kb
input:
1
output:
1
result:
ok 1 number(s): "1"
Test #2:
score: 0
Accepted
time: 54ms
memory: 162168kb
input:
2
output:
1
result:
ok 1 number(s): "1"
Test #3:
score: 0
Accepted
time: 42ms
memory: 162276kb
input:
10
output:
997920
result:
ok 1 number(s): "997920"
Test #4:
score: 0
Accepted
time: 37ms
memory: 162156kb
input:
100
output:
188898954
result:
ok 1 number(s): "188898954"
Test #5:
score: 0
Accepted
time: 35ms
memory: 162296kb
input:
4
output:
10
result:
ok 1 number(s): "10"
Test #6:
score: 0
Accepted
time: 40ms
memory: 162272kb
input:
8
output:
12336
result:
ok 1 number(s): "12336"
Test #7:
score: 0
Accepted
time: 37ms
memory: 162276kb
input:
16
output:
373118483
result:
ok 1 number(s): "373118483"
Test #8:
score: 0
Accepted
time: 38ms
memory: 162212kb
input:
32
output:
314585464
result:
ok 1 number(s): "314585464"
Test #9:
score: 0
Accepted
time: 57ms
memory: 162220kb
input:
64
output:
627827331
result:
ok 1 number(s): "627827331"
Test #10:
score: 0
Accepted
time: 53ms
memory: 162172kb
input:
128
output:
828497685
result:
ok 1 number(s): "828497685"
Test #11:
score: 0
Accepted
time: 38ms
memory: 160164kb
input:
256
output:
65697890
result:
ok 1 number(s): "65697890"
Test #12:
score: 0
Accepted
time: 31ms
memory: 162220kb
input:
512
output:
854187619
result:
ok 1 number(s): "854187619"
Test #13:
score: 0
Accepted
time: 39ms
memory: 162208kb
input:
1024
output:
513823539
result:
ok 1 number(s): "513823539"
Test #14:
score: 0
Accepted
time: 124ms
memory: 162164kb
input:
1361956
output:
617368199
result:
ok 1 number(s): "617368199"
Test #15:
score: 0
Accepted
time: 500ms
memory: 162148kb
input:
7579013
output:
827172636
result:
ok 1 number(s): "827172636"
Test #16:
score: 0
Accepted
time: 516ms
memory: 162240kb
input:
8145517
output:
710624331
result:
ok 1 number(s): "710624331"
Test #17:
score: 0
Accepted
time: 407ms
memory: 162216kb
input:
6140463
output:
707600568
result:
ok 1 number(s): "707600568"
Test #18:
score: 0
Accepted
time: 245ms
memory: 162300kb
input:
3515281
output:
698302413
result:
ok 1 number(s): "698302413"
Test #19:
score: 0
Accepted
time: 459ms
memory: 160164kb
input:
6969586
output:
69470392
result:
ok 1 number(s): "69470392"
Test #20:
score: 0
Accepted
time: 217ms
memory: 162172kb
input:
2888636
output:
433579983
result:
ok 1 number(s): "433579983"
Test #21:
score: 0
Accepted
time: 637ms
memory: 162148kb
input:
9999998
output:
758172780
result:
ok 1 number(s): "758172780"
Test #22:
score: 0
Accepted
time: 638ms
memory: 162212kb
input:
9999999
output:
605195495
result:
ok 1 number(s): "605195495"
Test #23:
score: 0
Accepted
time: 654ms
memory: 162216kb
input:
10000000
output:
866813682
result:
ok 1 number(s): "866813682"