QOJ.ac

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
#397026#6736. Alice and BobVictorYuan#AC ✓103ms81848kbC++141.1kb2024-04-23 15:45:452024-04-23 15:45:45

Judging History

你现在查看的是最新测评结果

  • [2024-04-23 15:45:45]
  • 评测
  • 测评结果:AC
  • 用时:103ms
  • 内存:81848kb
  • [2024-04-23 15:45:45]
  • 提交

answer

#include<bits/stdc++.h>

using namespace std;
const int mo = 998244353;
const int maxn = 1e7 + 7;
using ll = long long;
int fc[maxn],inv[maxn];
int qp(int a,int b) {
  int ans = 1,base = a;
  while(b != 0) {
    if(b & 1) ans = 1ll * ans * base % mo;
    base = 1ll * base * base % mo;
    b >>= 1;
  }
  return ans % mo;
}
int main() {
  int n;
  cin >> n;
  fc[0] = 1;
  for(int i = 1;i <= n;i ++) fc[i] = 1ll * fc[i - 1] * i % mo;
//  cerr << f1c[n - 1] << endl;
//  ll ans1 = fc[n - 1] * (n + 1) / 4; 
//  int inv2 = (mo + 1) / 2;
//  cerr << ans1 << " " << qp(2,mo - 2) << " " <<  (mo + 1) / 2 << endl;
//  int x = n / 2 - 1;
//  ll ans = 1ll * fc[n - 1] * (n + 1) % mo * qp(x,mo - 2) % mo;
  ll ans = 0;
  inv[n] = qp(fc[n],mo - 2);
  for(int i = n - 1;i >= 0;i --) inv[i] = 1ll * inv[i + 1] * (i + 1) % mo;
  auto A = [&](int n,int m) {
    return 1ll * fc[n] * inv[n - m] % mo;
  };
  for(int i = 1;i <= n;i ++) {
    if(i + i - 1 <= n) {
      
      ans += 1ll * A(n - i,i - 1) * fc[n - i] % mo;
      ans %= mo;
    }
  }
//  cerr << tmp << endl;
  cout << ans % mo << endl;
}

詳細信息

Test #1:

score: 100
Accepted
time: 1ms
memory: 5700kb

input:

1

output:

1

result:

ok 1 number(s): "1"

Test #2:

score: 0
Accepted
time: 1ms
memory: 5576kb

input:

2

output:

1

result:

ok 1 number(s): "1"

Test #3:

score: 0
Accepted
time: 1ms
memory: 5636kb

input:

10

output:

997920

result:

ok 1 number(s): "997920"

Test #4:

score: 0
Accepted
time: 1ms
memory: 5784kb

input:

100

output:

188898954

result:

ok 1 number(s): "188898954"

Test #5:

score: 0
Accepted
time: 1ms
memory: 5632kb

input:

4

output:

10

result:

ok 1 number(s): "10"

Test #6:

score: 0
Accepted
time: 1ms
memory: 5696kb

input:

8

output:

12336

result:

ok 1 number(s): "12336"

Test #7:

score: 0
Accepted
time: 1ms
memory: 5756kb

input:

16

output:

373118483

result:

ok 1 number(s): "373118483"

Test #8:

score: 0
Accepted
time: 1ms
memory: 5704kb

input:

32

output:

314585464

result:

ok 1 number(s): "314585464"

Test #9:

score: 0
Accepted
time: 1ms
memory: 5764kb

input:

64

output:

627827331

result:

ok 1 number(s): "627827331"

Test #10:

score: 0
Accepted
time: 1ms
memory: 5716kb

input:

128

output:

828497685

result:

ok 1 number(s): "828497685"

Test #11:

score: 0
Accepted
time: 1ms
memory: 5584kb

input:

256

output:

65697890

result:

ok 1 number(s): "65697890"

Test #12:

score: 0
Accepted
time: 0ms
memory: 5704kb

input:

512

output:

854187619

result:

ok 1 number(s): "854187619"

Test #13:

score: 0
Accepted
time: 0ms
memory: 5704kb

input:

1024

output:

513823539

result:

ok 1 number(s): "513823539"

Test #14:

score: 0
Accepted
time: 17ms
memory: 18728kb

input:

1361956

output:

617368199

result:

ok 1 number(s): "617368199"

Test #15:

score: 0
Accepted
time: 79ms
memory: 64396kb

input:

7579013

output:

827172636

result:

ok 1 number(s): "827172636"

Test #16:

score: 0
Accepted
time: 89ms
memory: 68956kb

input:

8145517

output:

710624331

result:

ok 1 number(s): "710624331"

Test #17:

score: 0
Accepted
time: 66ms
memory: 52356kb

input:

6140463

output:

707600568

result:

ok 1 number(s): "707600568"

Test #18:

score: 0
Accepted
time: 31ms
memory: 35300kb

input:

3515281

output:

698302413

result:

ok 1 number(s): "698302413"

Test #19:

score: 0
Accepted
time: 72ms
memory: 59896kb

input:

6969586

output:

69470392

result:

ok 1 number(s): "69470392"

Test #20:

score: 0
Accepted
time: 31ms
memory: 27924kb

input:

2888636

output:

433579983

result:

ok 1 number(s): "433579983"

Test #21:

score: 0
Accepted
time: 98ms
memory: 81828kb

input:

9999998

output:

758172780

result:

ok 1 number(s): "758172780"

Test #22:

score: 0
Accepted
time: 103ms
memory: 81848kb

input:

9999999

output:

605195495

result:

ok 1 number(s): "605195495"

Test #23:

score: 0
Accepted
time: 103ms
memory: 81776kb

input:

10000000

output:

866813682

result:

ok 1 number(s): "866813682"