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IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#142068#6736. Alice and BobOvO_ZuoAC ✓119ms81828kbC++141.0kb2023-08-18 13:37:152023-08-18 13:37:18

Judging History

你现在查看的是最新测评结果

  • [2023-08-18 13:37:18]
  • 评测
  • 测评结果:AC
  • 用时:119ms
  • 内存:81828kb
  • [2023-08-18 13:37:15]
  • 提交

answer

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N=1e7+5,mo=998244353;
int n,frac[N],inv[N];
int mi(int x,int y)
{
	int res=1;
	for(;y;y>>=1,x=(ll)x*x%mo)
		if(y&1) res=(ll)res*x%mo;
	return res;
}
int C(int x,int y)
{
	if(x<y) return 0;
	return (ll)frac[x]*inv[y]%mo*inv[x-y]%mo;
}
void init()
{
	int i,j;
	frac[0]=1;
	for(i=1;i<=n;i++) frac[i]=(ll)frac[i-1]*i%mo;
	inv[n]=mi(frac[n],mo-2);
	for(i=n-1;i>=0;--i) inv[i]=(ll)inv[i+1]*(i+1)%mo;
}
ll ans=0;
int main()
{
	scanf("%d",&n);
	int i,j;
	init();
	for(i=1;i<=n;i++)
		ans+=(ll)C(n-i,i-1)*frac[i-1]%mo*frac[n-i]%mo;
	ans%=mo;
	printf("%lld\n",ans);
	return 0;
}
/*
当 p[1]~p[p[1]] 中所有数都>=p[1] 时,后手一定能将p[1]再次调到序列首,先手必败
若存在小于的,则将最小的挪到 p[1] 的位置
设新的排列为 p',此时一定有 p'[1]~p'[p'[1]] 均 >=p'[1]
此时原先的后手必败
于是后手Bob胜利的充要条件就是p[1]~p[p[1]]之间所有数都>=p[1]
*/

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100
Accepted
time: 1ms
memory: 5924kb

input:

1

output:

1

result:

ok 1 number(s): "1"

Test #2:

score: 0
Accepted
time: 1ms
memory: 5888kb

input:

2

output:

1

result:

ok 1 number(s): "1"

Test #3:

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

input:

10

output:

997920

result:

ok 1 number(s): "997920"

Test #4:

score: 0
Accepted
time: 1ms
memory: 5760kb

input:

100

output:

188898954

result:

ok 1 number(s): "188898954"

Test #5:

score: 0
Accepted
time: 0ms
memory: 5928kb

input:

4

output:

10

result:

ok 1 number(s): "10"

Test #6:

score: 0
Accepted
time: 1ms
memory: 5700kb

input:

8

output:

12336

result:

ok 1 number(s): "12336"

Test #7:

score: 0
Accepted
time: 0ms
memory: 5776kb

input:

16

output:

373118483

result:

ok 1 number(s): "373118483"

Test #8:

score: 0
Accepted
time: 1ms
memory: 5672kb

input:

32

output:

314585464

result:

ok 1 number(s): "314585464"

Test #9:

score: 0
Accepted
time: 1ms
memory: 5760kb

input:

64

output:

627827331

result:

ok 1 number(s): "627827331"

Test #10:

score: 0
Accepted
time: 1ms
memory: 5712kb

input:

128

output:

828497685

result:

ok 1 number(s): "828497685"

Test #11:

score: 0
Accepted
time: 2ms
memory: 7980kb

input:

256

output:

65697890

result:

ok 1 number(s): "65697890"

Test #12:

score: 0
Accepted
time: 1ms
memory: 5684kb

input:

512

output:

854187619

result:

ok 1 number(s): "854187619"

Test #13:

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

input:

1024

output:

513823539

result:

ok 1 number(s): "513823539"

Test #14:

score: 0
Accepted
time: 16ms
memory: 19104kb

input:

1361956

output:

617368199

result:

ok 1 number(s): "617368199"

Test #15:

score: 0
Accepted
time: 90ms
memory: 63608kb

input:

7579013

output:

827172636

result:

ok 1 number(s): "827172636"

Test #16:

score: 0
Accepted
time: 82ms
memory: 67804kb

input:

8145517

output:

710624331

result:

ok 1 number(s): "710624331"

Test #17:

score: 0
Accepted
time: 66ms
memory: 52320kb

input:

6140463

output:

707600568

result:

ok 1 number(s): "707600568"

Test #18:

score: 0
Accepted
time: 45ms
memory: 33164kb

input:

3515281

output:

698302413

result:

ok 1 number(s): "698302413"

Test #19:

score: 0
Accepted
time: 79ms
memory: 59880kb

input:

6969586

output:

69470392

result:

ok 1 number(s): "69470392"

Test #20:

score: 0
Accepted
time: 30ms
memory: 26628kb

input:

2888636

output:

433579983

result:

ok 1 number(s): "433579983"

Test #21:

score: 0
Accepted
time: 113ms
memory: 81828kb

input:

9999998

output:

758172780

result:

ok 1 number(s): "758172780"

Test #22:

score: 0
Accepted
time: 110ms
memory: 81776kb

input:

9999999

output:

605195495

result:

ok 1 number(s): "605195495"

Test #23:

score: 0
Accepted
time: 119ms
memory: 81792kb

input:

10000000

output:

866813682

result:

ok 1 number(s): "866813682"