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QOJ

IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#190685#6736. Alice and Bobkoifish#AC ✓104ms159908kbC++171.7kb2023-09-29 12:50:222023-09-29 12:50:22

Judging History

你现在查看的是最新测评结果

  • [2023-09-29 12:50:22]
  • 评测
  • 测评结果:AC
  • 用时:104ms
  • 内存:159908kb
  • [2023-09-29 12:50:22]
  • 提交

answer

#include <bits/stdc++.h>
#define ll long long
#define int ll
#define mp make_pair
#define fi first
#define se second
#define pb push_back
#define vi vector<int>
#define pi pair<int, int>
#define vpii vector<pi>
#define il inline
#define ri register
#define all(a) a.begin(), a.end()
#define fr(a) freopen(a, "r", stdin)
#define fo(a) freopen(a, "w", stdout);
#define mod 998244353
#define debug puts("------------------------")
#define lowbit(x) (x&-x)
#define ls(x) x << 1
#define rs(x) x << 1 | 1
template<typename T> bool chkmin(T &a, T b){return (b < a) ? a = b, 1 : 0;}
template<typename T> bool chkmax(T &a, T b){return (b > a) ? a = b, 1 : 0;}
ll ksm(ll a, ll b) {if (b == 0) return 1; ll ns = ksm(a, b >> 1); ns = ns * ns % mod; if (b & 1) ns = ns * a % mod; return ns;}
void Read(int &a) {a=0;int c=getchar(),b=1; while(c>'9'||c<'0') {if(c=='-')b=-1;c=getchar();} while(c>='0'&&c<='9') a=(a<<3)+(a<<1)+c-48,c=getchar();a*=b; }
int  read() {int a=0,c=getchar(),b=1; while(c>'9'||c<'0') {if(c=='-')b=-1;c=getchar();} while(c>='0'&&c<='9') a=(a<<3)+(a<<1)+c-48,c=getchar();return a*=b; }
void write(int x) {if(x>9)write(x/10);putchar('0'+x%10);}
void W(int x) {if(x<0){putchar('-'),x=-x;}write(x);}
#define LOCAL
using namespace std;
const int maxn = 1e7 + 5;
/**/
int n, f[maxn], ans, ifac[maxn];
/**/
int A(int N, int M)
{
	if(N < M) return 0;
	return f[N] * ifac[N-M] % mod;
}
signed main()
{
	f[0] = ifac[0] = 1;
	n = read();
	for(int i = 1; i <= n; i++) f[i] = f[i - 1] * i % mod;
	ifac[n] = ksm(f[n], mod - 2);
	for(int i = n - 1; i >= 1; i--) ifac[i] = ifac[i + 1] * (i + 1) % mod;
	for(int i = 1; i <= n; i++)
	{
		ans += A(n-i, i-1) * A(n - i, n - i) % mod;
		ans %= mod;
	}
	cout << ans;
	return 0;
}

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100
Accepted
time: 1ms
memory: 5676kb

input:

1

output:

1

result:

ok 1 number(s): "1"

Test #2:

score: 0
Accepted
time: 1ms
memory: 5540kb

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: 0ms
memory: 5576kb

input:

100

output:

188898954

result:

ok 1 number(s): "188898954"

Test #5:

score: 0
Accepted
time: 0ms
memory: 5652kb

input:

4

output:

10

result:

ok 1 number(s): "10"

Test #6:

score: 0
Accepted
time: 1ms
memory: 5728kb

input:

8

output:

12336

result:

ok 1 number(s): "12336"

Test #7:

score: 0
Accepted
time: 0ms
memory: 5736kb

input:

16

output:

373118483

result:

ok 1 number(s): "373118483"

Test #8:

score: 0
Accepted
time: 1ms
memory: 5580kb

input:

32

output:

314585464

result:

ok 1 number(s): "314585464"

Test #9:

score: 0
Accepted
time: 0ms
memory: 5652kb

input:

64

output:

627827331

result:

ok 1 number(s): "627827331"

Test #10:

score: 0
Accepted
time: 1ms
memory: 5640kb

input:

128

output:

828497685

result:

ok 1 number(s): "828497685"

Test #11:

score: 0
Accepted
time: 0ms
memory: 5736kb

input:

256

output:

65697890

result:

ok 1 number(s): "65697890"

Test #12:

score: 0
Accepted
time: 0ms
memory: 5664kb

input:

512

output:

854187619

result:

ok 1 number(s): "854187619"

Test #13:

score: 0
Accepted
time: 1ms
memory: 5588kb

input:

1024

output:

513823539

result:

ok 1 number(s): "513823539"

Test #14:

score: 0
Accepted
time: 20ms
memory: 27776kb

input:

1361956

output:

617368199

result:

ok 1 number(s): "617368199"

Test #15:

score: 0
Accepted
time: 75ms
memory: 125596kb

input:

7579013

output:

827172636

result:

ok 1 number(s): "827172636"

Test #16:

score: 0
Accepted
time: 92ms
memory: 133472kb

input:

8145517

output:

710624331

result:

ok 1 number(s): "710624331"

Test #17:

score: 0
Accepted
time: 72ms
memory: 101976kb

input:

6140463

output:

707600568

result:

ok 1 number(s): "707600568"

Test #18:

score: 0
Accepted
time: 37ms
memory: 60028kb

input:

3515281

output:

698302413

result:

ok 1 number(s): "698302413"

Test #19:

score: 0
Accepted
time: 62ms
memory: 116952kb

input:

6969586

output:

69470392

result:

ok 1 number(s): "69470392"

Test #20:

score: 0
Accepted
time: 37ms
memory: 51932kb

input:

2888636

output:

433579983

result:

ok 1 number(s): "433579983"

Test #21:

score: 0
Accepted
time: 88ms
memory: 159908kb

input:

9999998

output:

758172780

result:

ok 1 number(s): "758172780"

Test #22:

score: 0
Accepted
time: 96ms
memory: 159844kb

input:

9999999

output:

605195495

result:

ok 1 number(s): "605195495"

Test #23:

score: 0
Accepted
time: 104ms
memory: 159904kb

input:

10000000

output:

866813682

result:

ok 1 number(s): "866813682"