QOJ.ac
QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#414427 | #6736. Alice and Bob | fuyouyufeng# | TL | 331ms | 26956kb | C++17 | 1.2kb | 2024-05-18 23:08:06 | 2024-05-18 23:08:07 |
Judging History
answer
#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
#define int long long
const int N = 1e7 + 10, mod = 998244353;
long long f[N], infact[N];
LL qmi(LL a, LL k, LL p)
{
LL res = 1;
while (k)
{
if (k & 1)
res = res * a % p;
a = a * a % p;
k >>= 1;
}
return res;
}
inline int c(int a, int b, int p) { return f[a] * infact[b] % p * infact[a - b] % p; }
void init_ass_two(int p, int n)
{
f[0] = infact[0] = 1;
// N的值是a和b的最大范围
for (int i = 1; i <= n; i++)
{
f[i] = i * f[i - 1] % p;
infact[i] = infact[i - 1] * qmi(i, p - 2, p) % p;
}
} // cout<<c(a,b,p)<<'\n';
signed main()
{
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n;
cin >> n;
init_ass_two(mod, n);
int mid = n / 2;
if (n % 2 == 1)
mid++;
int res = 0;
for (int i = 1; i <= mid; i++)
{
int x = 1;
x = (x * c(n - i, i - 1, mod)) % mod;
x = (x * f[i - 1]) % mod;
x = (x * f[n - i]) % mod;
res = (res + x) % mod;
}
cout << res ;
return 0;
}
Details
Tip: Click on the bar to expand more detailed information
Test #1:
score: 100
Accepted
time: 0ms
memory: 5688kb
input:
1
output:
1
result:
ok 1 number(s): "1"
Test #2:
score: 0
Accepted
time: 0ms
memory: 5652kb
input:
2
output:
1
result:
ok 1 number(s): "1"
Test #3:
score: 0
Accepted
time: 1ms
memory: 5592kb
input:
10
output:
997920
result:
ok 1 number(s): "997920"
Test #4:
score: 0
Accepted
time: 1ms
memory: 5668kb
input:
100
output:
188898954
result:
ok 1 number(s): "188898954"
Test #5:
score: 0
Accepted
time: 1ms
memory: 5652kb
input:
4
output:
10
result:
ok 1 number(s): "10"
Test #6:
score: 0
Accepted
time: 1ms
memory: 5728kb
input:
8
output:
12336
result:
ok 1 number(s): "12336"
Test #7:
score: 0
Accepted
time: 1ms
memory: 5616kb
input:
16
output:
373118483
result:
ok 1 number(s): "373118483"
Test #8:
score: 0
Accepted
time: 0ms
memory: 5592kb
input:
32
output:
314585464
result:
ok 1 number(s): "314585464"
Test #9:
score: 0
Accepted
time: 1ms
memory: 5664kb
input:
64
output:
627827331
result:
ok 1 number(s): "627827331"
Test #10:
score: 0
Accepted
time: 1ms
memory: 5684kb
input:
128
output:
828497685
result:
ok 1 number(s): "828497685"
Test #11:
score: 0
Accepted
time: 1ms
memory: 5676kb
input:
256
output:
65697890
result:
ok 1 number(s): "65697890"
Test #12:
score: 0
Accepted
time: 1ms
memory: 5672kb
input:
512
output:
854187619
result:
ok 1 number(s): "854187619"
Test #13:
score: 0
Accepted
time: 1ms
memory: 5608kb
input:
1024
output:
513823539
result:
ok 1 number(s): "513823539"
Test #14:
score: 0
Accepted
time: 331ms
memory: 26956kb
input:
1361956
output:
617368199
result:
ok 1 number(s): "617368199"
Test #15:
score: -100
Time Limit Exceeded
input:
7579013