QOJ.ac
QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#218518 | #6736. Alice and Bob | Fr1nGeLove# | TL | 960ms | 64400kb | C++20 | 923b | 2023-10-18 14:25:39 | 2023-10-18 14:25:39 |
Judging History
answer
#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
using namespace std;
using i64 = long long;
constexpr int N = 1E7 + 10, mod = 998244353;
int fac[N], invfac[N];
int qmi(int a, int b) {
int res = 1;
while (b) {
if (b & 1) {
res = (1LL * res * a) % mod;
}
a = (1LL * a * a) % mod;
b >>= 1;
}
return res;
}
int main() {
std::ios::sync_with_stdio(false);
std::cin.tie(nullptr);
int n;
cin >> n;
fac[0] = invfac[0] = 1;
for (int i = 1; i <= n; ++i) {
fac[i] = (1LL * fac[i - 1] * i) % mod;
invfac[i] = (1LL * invfac[i - 1] * qmi(i, mod - 2)) % mod;
}
int ans = 0;
for (int i = 1; i <= n; ++i) {
if (i - 1 > n - i) break;
int t;
if (i - 1 == 0) {
t = fac[n - i];
} else {
t = (1LL * (1LL * fac[n - i] * invfac[n - 2 * i + 1] % mod) * (fac[n - i])) % mod;
}
ans = (1LL * ans + t) % mod;
}
cout << ans << "\n";
return 0;
}
Details
Tip: Click on the bar to expand more detailed information
Test #1:
score: 100
Accepted
time: 1ms
memory: 5652kb
input:
1
output:
1
result:
ok 1 number(s): "1"
Test #2:
score: 0
Accepted
time: 1ms
memory: 5672kb
input:
2
output:
1
result:
ok 1 number(s): "1"
Test #3:
score: 0
Accepted
time: 0ms
memory: 5668kb
input:
10
output:
997920
result:
ok 1 number(s): "997920"
Test #4:
score: 0
Accepted
time: 0ms
memory: 5664kb
input:
100
output:
188898954
result:
ok 1 number(s): "188898954"
Test #5:
score: 0
Accepted
time: 1ms
memory: 5664kb
input:
4
output:
10
result:
ok 1 number(s): "10"
Test #6:
score: 0
Accepted
time: 0ms
memory: 5596kb
input:
8
output:
12336
result:
ok 1 number(s): "12336"
Test #7:
score: 0
Accepted
time: 1ms
memory: 5628kb
input:
16
output:
373118483
result:
ok 1 number(s): "373118483"
Test #8:
score: 0
Accepted
time: 1ms
memory: 5624kb
input:
32
output:
314585464
result:
ok 1 number(s): "314585464"
Test #9:
score: 0
Accepted
time: 1ms
memory: 5752kb
input:
64
output:
627827331
result:
ok 1 number(s): "627827331"
Test #10:
score: 0
Accepted
time: 1ms
memory: 5600kb
input:
128
output:
828497685
result:
ok 1 number(s): "828497685"
Test #11:
score: 0
Accepted
time: 1ms
memory: 5664kb
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: 5620kb
input:
1024
output:
513823539
result:
ok 1 number(s): "513823539"
Test #14:
score: 0
Accepted
time: 170ms
memory: 15312kb
input:
1361956
output:
617368199
result:
ok 1 number(s): "617368199"
Test #15:
score: 0
Accepted
time: 960ms
memory: 64400kb
input:
7579013
output:
827172636
result:
ok 1 number(s): "827172636"
Test #16:
score: -100
Time Limit Exceeded
input:
8145517
output:
710624331