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IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#370995#6736. Alice and Bobmikky#TL 5ms3688kbC++20992b2024-03-29 20:46:322024-03-29 20:48:01

Judging History

你现在查看的是最新测评结果

  • [2024-03-29 20:48:01]
  • 评测
  • 测评结果:TL
  • 用时:5ms
  • 内存:3688kb
  • [2024-03-29 20:46:32]
  • 提交

answer

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int N = 1e7 + 10;
const int mod = 998244353;

long long binpow(long long a, long long b) // 快速幂
{
	long long res = 1;
	while (b > 0)
	{
		if (b & 1)
			res = res * a % mod;
		a = a * a % mod;
		b >>= 1;
	}
	return res;
}

ll pailie(ll x)
{
	ll ans = 1;
	for (ll i = 1; i <= x; i++)
	{
		ans *= i;
		ans %= mod;
	}
	return ans % mod;
}
ll zuhe(ll x, ll y)
{
	ll ans;
	ans = ((pailie(x) * binpow(pailie(x - y), mod - 2)) % mod * binpow(pailie(y), mod - 2)) % mod; // 费马定理 a/b%n =a *pow(b,n-2)%n;n为质数
	return ans % mod;
}

void solve()
{
	ll n, ans = 0;
	cin >> n;

	ll tmp;
	for (ll i = 0; i < n; i++)
	{
		if (i > n - i-1)
			continue;
		ans += (zuhe(n - i - 1, i) % mod * pailie(i) % mod * pailie(n - i - 1) % mod) % mod;
		ans %= mod;
	}
	cout << ans << endl;
}

int main()
{
	ll _;
	_ = 1;
	// cin >> _;
	while (_--)
	{
		solve();
	}
}

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100
Accepted
time: 0ms
memory: 3488kb

input:

1

output:

1

result:

ok 1 number(s): "1"

Test #2:

score: 0
Accepted
time: 0ms
memory: 3596kb

input:

2

output:

1

result:

ok 1 number(s): "1"

Test #3:

score: 0
Accepted
time: 0ms
memory: 3688kb

input:

10

output:

997920

result:

ok 1 number(s): "997920"

Test #4:

score: 0
Accepted
time: 0ms
memory: 3600kb

input:

100

output:

188898954

result:

ok 1 number(s): "188898954"

Test #5:

score: 0
Accepted
time: 1ms
memory: 3488kb

input:

4

output:

10

result:

ok 1 number(s): "10"

Test #6:

score: 0
Accepted
time: 1ms
memory: 3568kb

input:

8

output:

12336

result:

ok 1 number(s): "12336"

Test #7:

score: 0
Accepted
time: 0ms
memory: 3660kb

input:

16

output:

373118483

result:

ok 1 number(s): "373118483"

Test #8:

score: 0
Accepted
time: 0ms
memory: 3608kb

input:

32

output:

314585464

result:

ok 1 number(s): "314585464"

Test #9:

score: 0
Accepted
time: 1ms
memory: 3596kb

input:

64

output:

627827331

result:

ok 1 number(s): "627827331"

Test #10:

score: 0
Accepted
time: 0ms
memory: 3544kb

input:

128

output:

828497685

result:

ok 1 number(s): "828497685"

Test #11:

score: 0
Accepted
time: 1ms
memory: 3608kb

input:

256

output:

65697890

result:

ok 1 number(s): "65697890"

Test #12:

score: 0
Accepted
time: 2ms
memory: 3488kb

input:

512

output:

854187619

result:

ok 1 number(s): "854187619"

Test #13:

score: 0
Accepted
time: 5ms
memory: 3528kb

input:

1024

output:

513823539

result:

ok 1 number(s): "513823539"

Test #14:

score: -100
Time Limit Exceeded

input:

1361956

output:


result: