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QOJ

IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#369631#6736. Alice and Bobkinoko777AC ✓116ms159952kbC++141.9kb2024-03-28 15:33:532024-03-28 15:33:53

Judging History

你现在查看的是最新测评结果

  • [2024-03-28 15:33:53]
  • 评测
  • 测评结果:AC
  • 用时:116ms
  • 内存:159952kb
  • [2024-03-28 15:33:53]
  • 提交

answer

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int, int> p11;
typedef pair<string, int> ps1;
typedef pair<ll, ll> p1111;
#define vv vector
#define pb emplace_back
#define IOS ios::sync_with_stdio(false); cin.tie(0); cout.tie(0)
#define fi first
#define se second
#define endl '\n'
#define Endl '\n'
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define per(a, b, c) for(int a = (b); a <= (c); a ++)
#define rep(a, b, c) for(int a = (b); a >= (c); a --)
#define aper(A) for(auto i : A) cout << i << ' ';cout << '\n'
#define lowbit(x) ((x) & (-x))
#define yes cout << "Yes" << endl
#define no cout << "No" << endl
#define YES cout << "YES" << endl
#define NO cout << "NO" << endl
#define PAI acos(-1)
#define int long long
using ll = long long;
void umin(int &x,int y){if(x>y)x=y;}
void umax(int &x,int y){if(x<y)x=y;}

int qsm(int a, int b, int p)
{
    int ans = 1;
    while(b)
    {
        if(b & 1) ans = ans * a % p;
        a = a * a % p;
        b >>= 1;
    }
    return ans;
}

const int mod = 998244353;
const int N = 1e7 + 10;

int fac[N], infac[N];

void pre_work()
{
    fac[0] = fac[1] = 1;
    for(int i = 2; i < N; i ++)
        fac[i] = fac[i - 1] * i % mod;
    infac[N - 1] = qsm(fac[N - 1], mod - 2, mod);
    for(int i = N - 2; i >= 1; i --)
    {
        infac[i] = infac[i + 1] * (i + 1) % mod;
    }
    infac[0] = infac[1] = 1;
}
int n;

int cal(int i)
{
    return fac[n - i] * fac[n - i] % mod * infac[n - 2 * i + 1] % mod;
}

void solve()
{
    cin >> n;
    int ans = 0;
    for(int i = 1; i <= n; i ++)
    {
        if(n - i < i - 1)  break;
        ans = (ans + cal(i)) % mod;
    }
    cout << ans << endl;
}

signed main()
{
  	IOS;
	int tt = 1;
	//cin >> tt;
	pre_work();
	while(tt --)
	{
		solve();
	}
	return 0;
}

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100
Accepted
time: 73ms
memory: 159920kb

input:

1

output:

1

result:

ok 1 number(s): "1"

Test #2:

score: 0
Accepted
time: 89ms
memory: 159948kb

input:

2

output:

1

result:

ok 1 number(s): "1"

Test #3:

score: 0
Accepted
time: 80ms
memory: 159796kb

input:

10

output:

997920

result:

ok 1 number(s): "997920"

Test #4:

score: 0
Accepted
time: 70ms
memory: 159856kb

input:

100

output:

188898954

result:

ok 1 number(s): "188898954"

Test #5:

score: 0
Accepted
time: 64ms
memory: 159952kb

input:

4

output:

10

result:

ok 1 number(s): "10"

Test #6:

score: 0
Accepted
time: 66ms
memory: 159816kb

input:

8

output:

12336

result:

ok 1 number(s): "12336"

Test #7:

score: 0
Accepted
time: 86ms
memory: 159928kb

input:

16

output:

373118483

result:

ok 1 number(s): "373118483"

Test #8:

score: 0
Accepted
time: 92ms
memory: 159900kb

input:

32

output:

314585464

result:

ok 1 number(s): "314585464"

Test #9:

score: 0
Accepted
time: 87ms
memory: 159868kb

input:

64

output:

627827331

result:

ok 1 number(s): "627827331"

Test #10:

score: 0
Accepted
time: 97ms
memory: 159856kb

input:

128

output:

828497685

result:

ok 1 number(s): "828497685"

Test #11:

score: 0
Accepted
time: 79ms
memory: 159868kb

input:

256

output:

65697890

result:

ok 1 number(s): "65697890"

Test #12:

score: 0
Accepted
time: 78ms
memory: 159876kb

input:

512

output:

854187619

result:

ok 1 number(s): "854187619"

Test #13:

score: 0
Accepted
time: 68ms
memory: 159808kb

input:

1024

output:

513823539

result:

ok 1 number(s): "513823539"

Test #14:

score: 0
Accepted
time: 91ms
memory: 159812kb

input:

1361956

output:

617368199

result:

ok 1 number(s): "617368199"

Test #15:

score: 0
Accepted
time: 89ms
memory: 159856kb

input:

7579013

output:

827172636

result:

ok 1 number(s): "827172636"

Test #16:

score: 0
Accepted
time: 84ms
memory: 159912kb

input:

8145517

output:

710624331

result:

ok 1 number(s): "710624331"

Test #17:

score: 0
Accepted
time: 116ms
memory: 159928kb

input:

6140463

output:

707600568

result:

ok 1 number(s): "707600568"

Test #18:

score: 0
Accepted
time: 82ms
memory: 159896kb

input:

3515281

output:

698302413

result:

ok 1 number(s): "698302413"

Test #19:

score: 0
Accepted
time: 88ms
memory: 159952kb

input:

6969586

output:

69470392

result:

ok 1 number(s): "69470392"

Test #20:

score: 0
Accepted
time: 92ms
memory: 159820kb

input:

2888636

output:

433579983

result:

ok 1 number(s): "433579983"

Test #21:

score: 0
Accepted
time: 106ms
memory: 159816kb

input:

9999998

output:

758172780

result:

ok 1 number(s): "758172780"

Test #22:

score: 0
Accepted
time: 101ms
memory: 159932kb

input:

9999999

output:

605195495

result:

ok 1 number(s): "605195495"

Test #23:

score: 0
Accepted
time: 102ms
memory: 159900kb

input:

10000000

output:

866813682

result:

ok 1 number(s): "866813682"