QOJ.ac
QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#395495 | #6736. Alice and Bob | frozen_wjl | AC ✓ | 141ms | 238112kb | C++23 | 941b | 2024-04-21 15:28:57 | 2024-04-21 15:28:57 |
Judging History
answer
#pragma GCC optimize(2)
#include<cmath>
#include<iostream>
#define mod 998244353
#define ll long long
#define N 10000005
using namespace std;
ll fac[N],inv1[N],inv0[N];
ll inv(ll t)
{
return t == 1 ? 1 : (mod - mod / t) * inv(mod % t) % mod;
}
void init()
{
int n = N-3;
fac[0] = 1;
inv1[0] = 1;
inv0[1] = 1;
fac[1] = fac[0]% mod;
inv1[1] = inv(1) * inv1[0] % mod;
for (int i = 2;i <= n;++i)
{
fac[i] = fac[i - 1] * i % mod;
inv0[i] = inv0[mod % i] * (mod - mod / i) % mod;
inv1[i] = inv0[i] * inv1[i - 1] % mod;
}
inv1[n] = inv(fac[n]);
}
ll A(ll a, ll b)
{
ll ret = 0;
if (b >= a)
return fac[a];
return fac[a] * inv1[a - b] % mod;
}
int main()
{
int n;
ll ans = 0;
cin >> n;
init();
for (int i = 0;i < n;++i)
{
if (n - 1 - i < i)
break;
else ans = (ans + A(n - 1 - i, i) * A(n - 1 - i, n - 1 - i) % mod) % mod;
}
cout << ans << "\n";
return 0;
}
Details
Tip: Click on the bar to expand more detailed information
Test #1:
score: 100
Accepted
time: 116ms
memory: 238028kb
input:
1
output:
1
result:
ok 1 number(s): "1"
Test #2:
score: 0
Accepted
time: 96ms
memory: 238108kb
input:
2
output:
1
result:
ok 1 number(s): "1"
Test #3:
score: 0
Accepted
time: 121ms
memory: 238040kb
input:
10
output:
997920
result:
ok 1 number(s): "997920"
Test #4:
score: 0
Accepted
time: 120ms
memory: 237956kb
input:
100
output:
188898954
result:
ok 1 number(s): "188898954"
Test #5:
score: 0
Accepted
time: 117ms
memory: 238028kb
input:
4
output:
10
result:
ok 1 number(s): "10"
Test #6:
score: 0
Accepted
time: 115ms
memory: 237968kb
input:
8
output:
12336
result:
ok 1 number(s): "12336"
Test #7:
score: 0
Accepted
time: 140ms
memory: 237960kb
input:
16
output:
373118483
result:
ok 1 number(s): "373118483"
Test #8:
score: 0
Accepted
time: 121ms
memory: 238024kb
input:
32
output:
314585464
result:
ok 1 number(s): "314585464"
Test #9:
score: 0
Accepted
time: 113ms
memory: 238052kb
input:
64
output:
627827331
result:
ok 1 number(s): "627827331"
Test #10:
score: 0
Accepted
time: 120ms
memory: 237996kb
input:
128
output:
828497685
result:
ok 1 number(s): "828497685"
Test #11:
score: 0
Accepted
time: 124ms
memory: 238084kb
input:
256
output:
65697890
result:
ok 1 number(s): "65697890"
Test #12:
score: 0
Accepted
time: 117ms
memory: 238112kb
input:
512
output:
854187619
result:
ok 1 number(s): "854187619"
Test #13:
score: 0
Accepted
time: 110ms
memory: 238024kb
input:
1024
output:
513823539
result:
ok 1 number(s): "513823539"
Test #14:
score: 0
Accepted
time: 119ms
memory: 238024kb
input:
1361956
output:
617368199
result:
ok 1 number(s): "617368199"
Test #15:
score: 0
Accepted
time: 127ms
memory: 238044kb
input:
7579013
output:
827172636
result:
ok 1 number(s): "827172636"
Test #16:
score: 0
Accepted
time: 141ms
memory: 237964kb
input:
8145517
output:
710624331
result:
ok 1 number(s): "710624331"
Test #17:
score: 0
Accepted
time: 127ms
memory: 238028kb
input:
6140463
output:
707600568
result:
ok 1 number(s): "707600568"
Test #18:
score: 0
Accepted
time: 137ms
memory: 238108kb
input:
3515281
output:
698302413
result:
ok 1 number(s): "698302413"
Test #19:
score: 0
Accepted
time: 131ms
memory: 237992kb
input:
6969586
output:
69470392
result:
ok 1 number(s): "69470392"
Test #20:
score: 0
Accepted
time: 115ms
memory: 238088kb
input:
2888636
output:
433579983
result:
ok 1 number(s): "433579983"
Test #21:
score: 0
Accepted
time: 131ms
memory: 238028kb
input:
9999998
output:
758172780
result:
ok 1 number(s): "758172780"
Test #22:
score: 0
Accepted
time: 126ms
memory: 237964kb
input:
9999999
output:
605195495
result:
ok 1 number(s): "605195495"
Test #23:
score: 0
Accepted
time: 127ms
memory: 238104kb
input:
10000000
output:
866813682
result:
ok 1 number(s): "866813682"