QOJ.ac
QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#370995 | #6736. Alice and Bob | mikky# | TL | 5ms | 3688kb | C++20 | 992b | 2024-03-29 20:46:32 | 2024-03-29 20:48:01 |
Judging History
answer
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int N = 1e7 + 10;
const int mod = 998244353;
long long binpow(long long a, long long b) // 快速幂
{
long long res = 1;
while (b > 0)
{
if (b & 1)
res = res * a % mod;
a = a * a % mod;
b >>= 1;
}
return res;
}
ll pailie(ll x)
{
ll ans = 1;
for (ll i = 1; i <= x; i++)
{
ans *= i;
ans %= mod;
}
return ans % mod;
}
ll zuhe(ll x, ll y)
{
ll ans;
ans = ((pailie(x) * binpow(pailie(x - y), mod - 2)) % mod * binpow(pailie(y), mod - 2)) % mod; // 费马定理 a/b%n =a *pow(b,n-2)%n;n为质数
return ans % mod;
}
void solve()
{
ll n, ans = 0;
cin >> n;
ll tmp;
for (ll i = 0; i < n; i++)
{
if (i > n - i-1)
continue;
ans += (zuhe(n - i - 1, i) % mod * pailie(i) % mod * pailie(n - i - 1) % mod) % mod;
ans %= mod;
}
cout << ans << endl;
}
int main()
{
ll _;
_ = 1;
// cin >> _;
while (_--)
{
solve();
}
}
Details
Tip: Click on the bar to expand more detailed information
Test #1:
score: 100
Accepted
time: 0ms
memory: 3488kb
input:
1
output:
1
result:
ok 1 number(s): "1"
Test #2:
score: 0
Accepted
time: 0ms
memory: 3596kb
input:
2
output:
1
result:
ok 1 number(s): "1"
Test #3:
score: 0
Accepted
time: 0ms
memory: 3688kb
input:
10
output:
997920
result:
ok 1 number(s): "997920"
Test #4:
score: 0
Accepted
time: 0ms
memory: 3600kb
input:
100
output:
188898954
result:
ok 1 number(s): "188898954"
Test #5:
score: 0
Accepted
time: 1ms
memory: 3488kb
input:
4
output:
10
result:
ok 1 number(s): "10"
Test #6:
score: 0
Accepted
time: 1ms
memory: 3568kb
input:
8
output:
12336
result:
ok 1 number(s): "12336"
Test #7:
score: 0
Accepted
time: 0ms
memory: 3660kb
input:
16
output:
373118483
result:
ok 1 number(s): "373118483"
Test #8:
score: 0
Accepted
time: 0ms
memory: 3608kb
input:
32
output:
314585464
result:
ok 1 number(s): "314585464"
Test #9:
score: 0
Accepted
time: 1ms
memory: 3596kb
input:
64
output:
627827331
result:
ok 1 number(s): "627827331"
Test #10:
score: 0
Accepted
time: 0ms
memory: 3544kb
input:
128
output:
828497685
result:
ok 1 number(s): "828497685"
Test #11:
score: 0
Accepted
time: 1ms
memory: 3608kb
input:
256
output:
65697890
result:
ok 1 number(s): "65697890"
Test #12:
score: 0
Accepted
time: 2ms
memory: 3488kb
input:
512
output:
854187619
result:
ok 1 number(s): "854187619"
Test #13:
score: 0
Accepted
time: 5ms
memory: 3528kb
input:
1024
output:
513823539
result:
ok 1 number(s): "513823539"
Test #14:
score: -100
Time Limit Exceeded
input:
1361956