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QOJ
ID | 题目 | 提交者 | 结果 | 用时 | 内存 | 语言 | 文件大小 | 提交时间 | 测评时间 |
---|---|---|---|---|---|---|---|---|---|
#350650 | #6736. Alice and Bob | Albert711 | RE | 2ms | 5248kb | C++20 | 1.5kb | 2024-03-10 22:34:38 | 2024-03-10 22:34:38 |
Judging History
answer
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef double db;
const int N = 1e5 + 5;
const int mod = 998244353;
//#define int long long
ll fpow(ll x, ll r) {
ll result = 1;
while (r) {
if (r & 1)result = result * x % mod;
r >>= 1;
x = x * x % mod;
}
return result;
}
namespace binom {
ll fac[N], ifac[N];
int __ = [] {
fac[0] = 1;
for (int i = 1; i <= N - 5; i++)
fac[i] = fac[i - 1] * i % mod;
ifac[N - 5] = fpow(fac[N - 5], mod - 2);
for (int i = N - 5; i; i--)
ifac[i - 1] = ifac[i] * i % mod;
return 0;
}();
inline ll C(int n, int m) {
if (n < m || m < 0)return 0;
return fac[n] * ifac[m] % mod * ifac[n - m] % mod;
}
inline ll A(int n, int m) {
if (n < m || m < 0)return 0;
return fac[n] * ifac[n - m] % mod;
}
}
using namespace binom;
void solve() {
ll n;
cin >> n;
if(n==1) {
cout<<1<<'\n';
return;
}
ll ans = 0;
ll tmp = 1;
for (int i = 1; i <= n - 1; i++) tmp = tmp * i % mod;
ll tt = tmp;
for (int i = 1; i <= n; i++) {
if (i - 1 > n - i) break;
ans = ans + A(n - i, i - 1) * tt % mod;
ans %= mod;
tt = tt * fpow(n - i, mod - 2) % mod;
}
cout << ans << '\n';
}
signed main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
// cout << fixed << setprecision(1);
int T = 1;
// cin >> T;
while (T--) solve();
return 0;
}
详细
Test #1:
score: 100
Accepted
time: 2ms
memory: 5216kb
input:
1
output:
1
result:
ok 1 number(s): "1"
Test #2:
score: 0
Accepted
time: 2ms
memory: 5192kb
input:
2
output:
1
result:
ok 1 number(s): "1"
Test #3:
score: 0
Accepted
time: 2ms
memory: 5200kb
input:
10
output:
997920
result:
ok 1 number(s): "997920"
Test #4:
score: 0
Accepted
time: 2ms
memory: 5120kb
input:
100
output:
188898954
result:
ok 1 number(s): "188898954"
Test #5:
score: 0
Accepted
time: 0ms
memory: 5136kb
input:
4
output:
10
result:
ok 1 number(s): "10"
Test #6:
score: 0
Accepted
time: 2ms
memory: 5168kb
input:
8
output:
12336
result:
ok 1 number(s): "12336"
Test #7:
score: 0
Accepted
time: 1ms
memory: 5120kb
input:
16
output:
373118483
result:
ok 1 number(s): "373118483"
Test #8:
score: 0
Accepted
time: 2ms
memory: 5180kb
input:
32
output:
314585464
result:
ok 1 number(s): "314585464"
Test #9:
score: 0
Accepted
time: 0ms
memory: 5120kb
input:
64
output:
627827331
result:
ok 1 number(s): "627827331"
Test #10:
score: 0
Accepted
time: 1ms
memory: 5192kb
input:
128
output:
828497685
result:
ok 1 number(s): "828497685"
Test #11:
score: 0
Accepted
time: 0ms
memory: 5196kb
input:
256
output:
65697890
result:
ok 1 number(s): "65697890"
Test #12:
score: 0
Accepted
time: 2ms
memory: 5248kb
input:
512
output:
854187619
result:
ok 1 number(s): "854187619"
Test #13:
score: 0
Accepted
time: 2ms
memory: 5184kb
input:
1024
output:
513823539
result:
ok 1 number(s): "513823539"
Test #14:
score: -100
Runtime Error
input:
1361956