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QOJ

IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#410992#6736. Alice and BobSnowNorthAC ✓112ms159968kbC++14862b2024-05-14 19:39:552024-05-14 19:39:56

Judging History

你现在查看的是最新测评结果

  • [2024-05-14 19:39:56]
  • 评测
  • 测评结果:AC
  • 用时:112ms
  • 内存:159968kb
  • [2024-05-14 19:39:55]
  • 提交

answer

#include <bits/stdc++.h>
#define mod 998244353
using namespace std;

const int N = 1e7 + 10;
using ll = long long ;

ll mul[N], inv[N];

ll qpow(ll x, ll n) {
	ll res = 1;
	while (n > 0) {
		if (n & 1) res = res * x % mod;
		x = x * x % mod;
		n >>= 1;
	}
	return res;
}

void prework() {
	mul[0] = 1;
	for (int i = 1; i < N; i++) {
		mul[i] = mul[i - 1] * i % mod;
	}
	
	inv[N - 1] = qpow(mul[N - 1], mod - 2);
	for (int i = N - 2; i >= 0; i--) {
		inv[i] = inv[i + 1] * (i + 1) % mod;
	}
}

void qwq()
{
	ll ans = 0;
	int n;
	cin >> n;
	
	for (int i = 1; i <= n; i++) {
		if (i - 1 <= n - i) {
			ans += mul[n - i] * mul[n - i] % mod * inv[n - i * 2 + 1] % mod;
			ans %= mod;
		}
	}
	
	cout << ans;
}

signed main()
{
	ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
	prework();
	qwq();
	return 0;
} 

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100
Accepted
time: 88ms
memory: 159756kb

input:

1

output:

1

result:

ok 1 number(s): "1"

Test #2:

score: 0
Accepted
time: 84ms
memory: 159792kb

input:

2

output:

1

result:

ok 1 number(s): "1"

Test #3:

score: 0
Accepted
time: 79ms
memory: 159952kb

input:

10

output:

997920

result:

ok 1 number(s): "997920"

Test #4:

score: 0
Accepted
time: 88ms
memory: 159808kb

input:

100

output:

188898954

result:

ok 1 number(s): "188898954"

Test #5:

score: 0
Accepted
time: 80ms
memory: 159896kb

input:

4

output:

10

result:

ok 1 number(s): "10"

Test #6:

score: 0
Accepted
time: 84ms
memory: 159888kb

input:

8

output:

12336

result:

ok 1 number(s): "12336"

Test #7:

score: 0
Accepted
time: 92ms
memory: 159904kb

input:

16

output:

373118483

result:

ok 1 number(s): "373118483"

Test #8:

score: 0
Accepted
time: 80ms
memory: 159816kb

input:

32

output:

314585464

result:

ok 1 number(s): "314585464"

Test #9:

score: 0
Accepted
time: 79ms
memory: 159968kb

input:

64

output:

627827331

result:

ok 1 number(s): "627827331"

Test #10:

score: 0
Accepted
time: 84ms
memory: 159888kb

input:

128

output:

828497685

result:

ok 1 number(s): "828497685"

Test #11:

score: 0
Accepted
time: 84ms
memory: 159952kb

input:

256

output:

65697890

result:

ok 1 number(s): "65697890"

Test #12:

score: 0
Accepted
time: 93ms
memory: 159948kb

input:

512

output:

854187619

result:

ok 1 number(s): "854187619"

Test #13:

score: 0
Accepted
time: 84ms
memory: 159952kb

input:

1024

output:

513823539

result:

ok 1 number(s): "513823539"

Test #14:

score: 0
Accepted
time: 92ms
memory: 159952kb

input:

1361956

output:

617368199

result:

ok 1 number(s): "617368199"

Test #15:

score: 0
Accepted
time: 102ms
memory: 159948kb

input:

7579013

output:

827172636

result:

ok 1 number(s): "827172636"

Test #16:

score: 0
Accepted
time: 94ms
memory: 159816kb

input:

8145517

output:

710624331

result:

ok 1 number(s): "710624331"

Test #17:

score: 0
Accepted
time: 102ms
memory: 159876kb

input:

6140463

output:

707600568

result:

ok 1 number(s): "707600568"

Test #18:

score: 0
Accepted
time: 99ms
memory: 159816kb

input:

3515281

output:

698302413

result:

ok 1 number(s): "698302413"

Test #19:

score: 0
Accepted
time: 96ms
memory: 159960kb

input:

6969586

output:

69470392

result:

ok 1 number(s): "69470392"

Test #20:

score: 0
Accepted
time: 91ms
memory: 159852kb

input:

2888636

output:

433579983

result:

ok 1 number(s): "433579983"

Test #21:

score: 0
Accepted
time: 110ms
memory: 159884kb

input:

9999998

output:

758172780

result:

ok 1 number(s): "758172780"

Test #22:

score: 0
Accepted
time: 110ms
memory: 159948kb

input:

9999999

output:

605195495

result:

ok 1 number(s): "605195495"

Test #23:

score: 0
Accepted
time: 112ms
memory: 159912kb

input:

10000000

output:

866813682

result:

ok 1 number(s): "866813682"