QOJ.ac
QOJ
| ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
|---|---|---|---|---|---|---|---|---|---|
| #246006 | #6736. Alice and Bob | Colblue# | AC ✓ | 123ms | 159816kb | C++14 | 1000b | 2023-11-10 15:19:17 | 2023-11-10 15:19:18 |
Judging History
answer
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll MOD = 998244353, N = 1e7 + 1;
ll n, p[N], inv[N];
ll ksm (ll x, ll y) {
ll ret = 1, now = x;
while (y) {
if (y & 1) {
ret *= now;
ret %= MOD;
}
now *= now;
now %= MOD;
y >>= 1;
}
return ret;
}
int main () {
cin >> n;
p[0] = 1;
for (ll i = 1; i <= n; i ++)
p[i] = p[i - 1] * i % MOD;
inv[n] = ksm (p[n], MOD - 2);
for (ll i = n; i >= 1; i --)
inv[i - 1] = inv[i] * i % MOD;
ll ans = 0;
for (ll i = 1; i <= n; i ++) {
if (i == 1) {
ans += p[n - 1]; ans %= MOD; continue ;
}
if (n - 2 * i + 2 <= 0)
break ;
ans += p[n - i] * p[n - i] % MOD * inv[n - 2 * i + 1] % MOD;
// cout << p[n - i] * p[n - i] % MOD * inv[n - 2 * i + 1] % MOD << endl;
ans %= MOD;
}
cout << ans;
return 0;
}
Details
Tip: Click on the bar to expand more detailed information
Test #1:
score: 100
Accepted
time: 1ms
memory: 5376kb
input:
1
output:
1
result:
ok 1 number(s): "1"
Test #2:
score: 0
Accepted
time: 1ms
memory: 5420kb
input:
2
output:
1
result:
ok 1 number(s): "1"
Test #3:
score: 0
Accepted
time: 1ms
memory: 5384kb
input:
10
output:
997920
result:
ok 1 number(s): "997920"
Test #4:
score: 0
Accepted
time: 1ms
memory: 5616kb
input:
100
output:
188898954
result:
ok 1 number(s): "188898954"
Test #5:
score: 0
Accepted
time: 1ms
memory: 5564kb
input:
4
output:
10
result:
ok 1 number(s): "10"
Test #6:
score: 0
Accepted
time: 1ms
memory: 5424kb
input:
8
output:
12336
result:
ok 1 number(s): "12336"
Test #7:
score: 0
Accepted
time: 1ms
memory: 5384kb
input:
16
output:
373118483
result:
ok 1 number(s): "373118483"
Test #8:
score: 0
Accepted
time: 0ms
memory: 5420kb
input:
32
output:
314585464
result:
ok 1 number(s): "314585464"
Test #9:
score: 0
Accepted
time: 1ms
memory: 5460kb
input:
64
output:
627827331
result:
ok 1 number(s): "627827331"
Test #10:
score: 0
Accepted
time: 0ms
memory: 5560kb
input:
128
output:
828497685
result:
ok 1 number(s): "828497685"
Test #11:
score: 0
Accepted
time: 1ms
memory: 5432kb
input:
256
output:
65697890
result:
ok 1 number(s): "65697890"
Test #12:
score: 0
Accepted
time: 1ms
memory: 5384kb
input:
512
output:
854187619
result:
ok 1 number(s): "854187619"
Test #13:
score: 0
Accepted
time: 1ms
memory: 5572kb
input:
1024
output:
513823539
result:
ok 1 number(s): "513823539"
Test #14:
score: 0
Accepted
time: 18ms
memory: 28092kb
input:
1361956
output:
617368199
result:
ok 1 number(s): "617368199"
Test #15:
score: 0
Accepted
time: 78ms
memory: 124968kb
input:
7579013
output:
827172636
result:
ok 1 number(s): "827172636"
Test #16:
score: 0
Accepted
time: 95ms
memory: 133688kb
input:
8145517
output:
710624331
result:
ok 1 number(s): "710624331"
Test #17:
score: 0
Accepted
time: 46ms
memory: 101428kb
input:
6140463
output:
707600568
result:
ok 1 number(s): "707600568"
Test #18:
score: 0
Accepted
time: 22ms
memory: 60160kb
input:
3515281
output:
698302413
result:
ok 1 number(s): "698302413"
Test #19:
score: 0
Accepted
time: 40ms
memory: 113792kb
input:
6969586
output:
69470392
result:
ok 1 number(s): "69470392"
Test #20:
score: 0
Accepted
time: 33ms
memory: 51960kb
input:
2888636
output:
433579983
result:
ok 1 number(s): "433579983"
Test #21:
score: 0
Accepted
time: 123ms
memory: 159816kb
input:
9999998
output:
758172780
result:
ok 1 number(s): "758172780"
Test #22:
score: 0
Accepted
time: 114ms
memory: 159624kb
input:
9999999
output:
605195495
result:
ok 1 number(s): "605195495"
Test #23:
score: 0
Accepted
time: 114ms
memory: 159616kb
input:
10000000
output:
866813682
result:
ok 1 number(s): "866813682"