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IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#395487#6736. Alice and Bobfrozen_wjlWA 701ms85896kbC++23775b2024-04-21 15:18:532024-04-21 15:18:53

Judging History

你现在查看的是最新测评结果

  • [2024-04-21 15:18:53]
  • 评测
  • 测评结果:WA
  • 用时:701ms
  • 内存:85896kb
  • [2024-04-21 15:18:53]
  • 提交

answer

#include<cmath>
#include<iostream>
#define mod 998244353
#define ll long long
#define N 10000005
using namespace std;

ll fac[N],inv1[N];
ll inv(ll t)
{
	return t == 1 ? 1 : (mod - mod / t) * inv(mod % t) % mod;
}

void init()
{
	int n = (N - 4)/2;
	fac[0] = 1;
	inv1[0] = 1;
	for (int i = 1;i <= n;++i)
		fac[i] = fac[i - 1] * i % mod, inv1[i] = inv(i) * inv1[i - 1] % mod;
	inv1[n] = inv(fac[n]);
}
ll A(ll a, ll b)
{
	ll ret = 0;
	if (b >= a)
		return fac[a];
	return fac[a] * inv1[a - b] % mod;
}
int main()
{
	int n;
	ll ans = 0;
	cin >> n;
	init();
	
	for (int i = 0;i < n;++i)
	{
		if (n - 1 - i < i)
			break;
		else ans = (ans + A(n - 1 - i, i) * A(n - 1 - i, n - 1 - i) % mod) % mod;
	}
	cout << ans << "\n";
	return 0;
}

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100
Accepted
time: 699ms
memory: 84372kb

input:

1

output:

1

result:

ok 1 number(s): "1"

Test #2:

score: 0
Accepted
time: 689ms
memory: 83988kb

input:

2

output:

1

result:

ok 1 number(s): "1"

Test #3:

score: 0
Accepted
time: 685ms
memory: 85068kb

input:

10

output:

997920

result:

ok 1 number(s): "997920"

Test #4:

score: 0
Accepted
time: 694ms
memory: 84236kb

input:

100

output:

188898954

result:

ok 1 number(s): "188898954"

Test #5:

score: 0
Accepted
time: 686ms
memory: 84184kb

input:

4

output:

10

result:

ok 1 number(s): "10"

Test #6:

score: 0
Accepted
time: 701ms
memory: 84496kb

input:

8

output:

12336

result:

ok 1 number(s): "12336"

Test #7:

score: 0
Accepted
time: 685ms
memory: 85628kb

input:

16

output:

373118483

result:

ok 1 number(s): "373118483"

Test #8:

score: 0
Accepted
time: 684ms
memory: 84596kb

input:

32

output:

314585464

result:

ok 1 number(s): "314585464"

Test #9:

score: 0
Accepted
time: 689ms
memory: 84176kb

input:

64

output:

627827331

result:

ok 1 number(s): "627827331"

Test #10:

score: 0
Accepted
time: 693ms
memory: 85144kb

input:

128

output:

828497685

result:

ok 1 number(s): "828497685"

Test #11:

score: 0
Accepted
time: 697ms
memory: 84884kb

input:

256

output:

65697890

result:

ok 1 number(s): "65697890"

Test #12:

score: 0
Accepted
time: 682ms
memory: 83660kb

input:

512

output:

854187619

result:

ok 1 number(s): "854187619"

Test #13:

score: 0
Accepted
time: 690ms
memory: 85896kb

input:

1024

output:

513823539

result:

ok 1 number(s): "513823539"

Test #14:

score: 0
Accepted
time: 696ms
memory: 84996kb

input:

1361956

output:

617368199

result:

ok 1 number(s): "617368199"

Test #15:

score: -100
Wrong Answer
time: 695ms
memory: 85144kb

input:

7579013

output:

637920959

result:

wrong answer 1st numbers differ - expected: '827172636', found: '637920959'