QOJ.ac
QOJ
| ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
|---|---|---|---|---|---|---|---|---|---|
| #394456 | #6736. Alice and Bob | Lo# | AC ✓ | 127ms | 159952kb | C++14 | 656b | 2024-04-20 14:53:07 | 2024-04-20 14:53:07 |
Judging History
answer
#include <bits/stdc++.h>
using namespace std;
const int N=1e7+5;
using LL=long long;
const LL mod=998244353;
LL fac[N],inv[N];
LL poww(LL a,LL b)
{
LL ans=1;
for (;b;b>>=1,a=a*a%mod)
if (b&1) ans=ans*a%mod;
return ans;
}
LL A(LL n,LL m)
{
if (n<m) return 0;
return fac[n]*inv[n-m]%mod;
}
int main()
{
int n;
cin>>n;
fac[0]=1;
for (int i=1;i<=n;++i) fac[i]=fac[i-1]*i%mod;
inv[n]=poww(fac[n],mod-2);
for (int i=n;i>=1;--i) inv[i-1]=inv[i]*i%mod;
// cout<<inv[1]<<inv[2]<<"\n";
LL ans=0;
for (int i=1;i<=n;++i)
{
ans=(ans+A(n-i,i-1)*A(n-i,n-i)%mod)%mod;
// cout<<A(n-i,i-1)*A()<<"\n";
}
cout<<ans;
}
Details
Tip: Click on the bar to expand more detailed information
Test #1:
score: 100
Accepted
time: 1ms
memory: 5676kb
input:
1
output:
1
result:
ok 1 number(s): "1"
Test #2:
score: 0
Accepted
time: 0ms
memory: 5684kb
input:
2
output:
1
result:
ok 1 number(s): "1"
Test #3:
score: 0
Accepted
time: 1ms
memory: 5712kb
input:
10
output:
997920
result:
ok 1 number(s): "997920"
Test #4:
score: 0
Accepted
time: 0ms
memory: 5560kb
input:
100
output:
188898954
result:
ok 1 number(s): "188898954"
Test #5:
score: 0
Accepted
time: 1ms
memory: 5600kb
input:
4
output:
10
result:
ok 1 number(s): "10"
Test #6:
score: 0
Accepted
time: 1ms
memory: 5736kb
input:
8
output:
12336
result:
ok 1 number(s): "12336"
Test #7:
score: 0
Accepted
time: 0ms
memory: 5740kb
input:
16
output:
373118483
result:
ok 1 number(s): "373118483"
Test #8:
score: 0
Accepted
time: 1ms
memory: 5672kb
input:
32
output:
314585464
result:
ok 1 number(s): "314585464"
Test #9:
score: 0
Accepted
time: 1ms
memory: 5684kb
input:
64
output:
627827331
result:
ok 1 number(s): "627827331"
Test #10:
score: 0
Accepted
time: 1ms
memory: 5616kb
input:
128
output:
828497685
result:
ok 1 number(s): "828497685"
Test #11:
score: 0
Accepted
time: 1ms
memory: 5684kb
input:
256
output:
65697890
result:
ok 1 number(s): "65697890"
Test #12:
score: 0
Accepted
time: 1ms
memory: 5684kb
input:
512
output:
854187619
result:
ok 1 number(s): "854187619"
Test #13:
score: 0
Accepted
time: 1ms
memory: 5616kb
input:
1024
output:
513823539
result:
ok 1 number(s): "513823539"
Test #14:
score: 0
Accepted
time: 12ms
memory: 27492kb
input:
1361956
output:
617368199
result:
ok 1 number(s): "617368199"
Test #15:
score: 0
Accepted
time: 100ms
memory: 123520kb
input:
7579013
output:
827172636
result:
ok 1 number(s): "827172636"
Test #16:
score: 0
Accepted
time: 101ms
memory: 131440kb
input:
8145517
output:
710624331
result:
ok 1 number(s): "710624331"
Test #17:
score: 0
Accepted
time: 60ms
memory: 99852kb
input:
6140463
output:
707600568
result:
ok 1 number(s): "707600568"
Test #18:
score: 0
Accepted
time: 51ms
memory: 59940kb
input:
3515281
output:
698302413
result:
ok 1 number(s): "698302413"
Test #19:
score: 0
Accepted
time: 91ms
memory: 112620kb
input:
6969586
output:
69470392
result:
ok 1 number(s): "69470392"
Test #20:
score: 0
Accepted
time: 35ms
memory: 50696kb
input:
2888636
output:
433579983
result:
ok 1 number(s): "433579983"
Test #21:
score: 0
Accepted
time: 115ms
memory: 159952kb
input:
9999998
output:
758172780
result:
ok 1 number(s): "758172780"
Test #22:
score: 0
Accepted
time: 112ms
memory: 159876kb
input:
9999999
output:
605195495
result:
ok 1 number(s): "605195495"
Test #23:
score: 0
Accepted
time: 127ms
memory: 159880kb
input:
10000000
output:
866813682
result:
ok 1 number(s): "866813682"