QOJ.ac
QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#183999 | #6736. Alice and Bob | 0x3ea | AC ✓ | 168ms | 159788kb | C++14 | 1.5kb | 2023-09-20 09:47:08 | 2023-09-20 09:47:08 |
Judging History
answer
#pragma GCC optimize(2)
#include <bits/stdc++.h>
#define endl '\n'
#define x first
#define y second
#define stop cout << "?" << '\n'
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
const int N = 1e7 + 10, M = 7e5;
const ll mod = 998244353;
const double pi = acos(-1);
int n, m;
ll fac[N], invfac[N];
ll qmi(ll a, ll b = mod - 2)
{
a %= mod;
ll res = 1;
while (b)
{
if (b & 1)
res = res * a % mod;
b >>= 1;
a = a * a % mod;
}
return res;
}
void init()
{
// int n = 1e7+10;
fac[0] = 1; // fac[i]表示i的阶乘,invfac[i]表示i的阶乘的逆元
for (int i = 1; i <= n; i++)
fac[i] = fac[i - 1] * i % mod;
invfac[n] = qmi(fac[n]); // 快速幂
for (int i = n - 1; i >= 0; i--)
invfac[i] = invfac[i + 1] * (i + 1) % mod;
// C(n,m)=fac[n] * invfac[m] % mod * invfac[n - m] % mod;
}
ll C(int n, int m)
{
if (n < m || m < 0) // 注意判断是否合法
return 0;
return fac[n] * invfac[m] % mod * invfac[n - m] % mod;
}
void solve()
{
cin >> n;
init();
ll ans = 0;
for (int i = 1; i <= n; i++)
{
ll res = C(n - i, i - 1) * fac[n - i] % mod * fac[i - 1] % mod;
ans = (ans + res) % mod;
// cout << C(1, 0) << endl;
// ans %= mod;
}
cout << ans << endl;
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int _ = 1;
// cin >> _;
while (_--)
solve();
return 0;
}
Details
Tip: Click on the bar to expand more detailed information
Test #1:
score: 100
Accepted
time: 1ms
memory: 5612kb
input:
1
output:
1
result:
ok 1 number(s): "1"
Test #2:
score: 0
Accepted
time: 1ms
memory: 5472kb
input:
2
output:
1
result:
ok 1 number(s): "1"
Test #3:
score: 0
Accepted
time: 1ms
memory: 5480kb
input:
10
output:
997920
result:
ok 1 number(s): "997920"
Test #4:
score: 0
Accepted
time: 0ms
memory: 5488kb
input:
100
output:
188898954
result:
ok 1 number(s): "188898954"
Test #5:
score: 0
Accepted
time: 1ms
memory: 5424kb
input:
4
output:
10
result:
ok 1 number(s): "10"
Test #6:
score: 0
Accepted
time: 1ms
memory: 5472kb
input:
8
output:
12336
result:
ok 1 number(s): "12336"
Test #7:
score: 0
Accepted
time: 0ms
memory: 5500kb
input:
16
output:
373118483
result:
ok 1 number(s): "373118483"
Test #8:
score: 0
Accepted
time: 1ms
memory: 5432kb
input:
32
output:
314585464
result:
ok 1 number(s): "314585464"
Test #9:
score: 0
Accepted
time: 1ms
memory: 5648kb
input:
64
output:
627827331
result:
ok 1 number(s): "627827331"
Test #10:
score: 0
Accepted
time: 1ms
memory: 5608kb
input:
128
output:
828497685
result:
ok 1 number(s): "828497685"
Test #11:
score: 0
Accepted
time: 1ms
memory: 5652kb
input:
256
output:
65697890
result:
ok 1 number(s): "65697890"
Test #12:
score: 0
Accepted
time: 1ms
memory: 5380kb
input:
512
output:
854187619
result:
ok 1 number(s): "854187619"
Test #13:
score: 0
Accepted
time: 1ms
memory: 5496kb
input:
1024
output:
513823539
result:
ok 1 number(s): "513823539"
Test #14:
score: 0
Accepted
time: 16ms
memory: 28668kb
input:
1361956
output:
617368199
result:
ok 1 number(s): "617368199"
Test #15:
score: 0
Accepted
time: 88ms
memory: 125260kb
input:
7579013
output:
827172636
result:
ok 1 number(s): "827172636"
Test #16:
score: 0
Accepted
time: 86ms
memory: 133440kb
input:
8145517
output:
710624331
result:
ok 1 number(s): "710624331"
Test #17:
score: 0
Accepted
time: 104ms
memory: 101656kb
input:
6140463
output:
707600568
result:
ok 1 number(s): "707600568"
Test #18:
score: 0
Accepted
time: 60ms
memory: 60664kb
input:
3515281
output:
698302413
result:
ok 1 number(s): "698302413"
Test #19:
score: 0
Accepted
time: 105ms
memory: 113644kb
input:
6969586
output:
69470392
result:
ok 1 number(s): "69470392"
Test #20:
score: 0
Accepted
time: 46ms
memory: 51248kb
input:
2888636
output:
433579983
result:
ok 1 number(s): "433579983"
Test #21:
score: 0
Accepted
time: 111ms
memory: 159700kb
input:
9999998
output:
758172780
result:
ok 1 number(s): "758172780"
Test #22:
score: 0
Accepted
time: 143ms
memory: 159672kb
input:
9999999
output:
605195495
result:
ok 1 number(s): "605195495"
Test #23:
score: 0
Accepted
time: 168ms
memory: 159788kb
input:
10000000
output:
866813682
result:
ok 1 number(s): "866813682"