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QOJ

IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#408051#6736. Alice and BobAdo1phosaAC ✓133ms159912kbC++171.5kb2024-05-09 16:59:332024-05-09 16:59:34

Judging History

你现在查看的是最新测评结果

  • [2024-05-09 16:59:34]
  • 评测
  • 测评结果:AC
  • 用时:133ms
  • 内存:159912kb
  • [2024-05-09 16:59:33]
  • 提交

answer

#include <bits/stdc++.h>

using namespace std;
#define int long long
#define rep(i, l, r) for(int i = l; i <= (int)r; i ++)
#define debug(a) cout << #a << " = " << a << '\n';
#define debug2(a, b) cout << #a << " = " << a << "  " << #b << " = " << b << '\n';
const int N = 1e7 + 3, mod = 998244353;


int n;
const int p = 998244353;
namespace CNM {
    const int N = 1e7 + 4;
    int fac[N], infac[N];
    int ksm(int x, int y) {
        int res = 1;
        while(y > 0) {
            if(y & 1)
                res = res * x % p;
            y >>= 1;
            x = x * x % p;
        }
        return res;
    }
    void init() {
        fac[0] = 1;
        for(int i = 1; i < N; i ++)
            fac[i] = fac[i - 1] * i % p;
        infac[N - 1] = ksm(fac[N - 1], p - 2);
        for(int i = N - 2; i >= 0; i --)
            infac[i] = infac[i + 1] * (i + 1) % p;
    }
    int C(int n, int m) {
        if(n < m || m < 0) return 0;
        return (fac[n] * infac[m] % p) * infac[n - m] % p;
    }
    int A(int n, int m) {
    	if(n < m || m < 0) return 0;
    	return fac[n] * infac[n - m] % mod;
    }
}
int A(int n, int m) {
	return CNM::A(n, m);
}
void solve() {
	cin >> n;

	CNM::init();

	int ans = 0;
	for(int i = 1; i <= n; i ++) {
		ans += A(n - i, i - 1) * A(n - i, n - i) % mod;
		ans %= mod;
	}
	cout << ans << '\n';
}
main() {
    ios::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);
    int _ = 1;
    // cin >> _;
    while(_ --) {
    	solve();
    }
    return 0;
}

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100
Accepted
time: 94ms
memory: 159852kb

input:

1

output:

1

result:

ok 1 number(s): "1"

Test #2:

score: 0
Accepted
time: 96ms
memory: 159868kb

input:

2

output:

1

result:

ok 1 number(s): "1"

Test #3:

score: 0
Accepted
time: 92ms
memory: 159772kb

input:

10

output:

997920

result:

ok 1 number(s): "997920"

Test #4:

score: 0
Accepted
time: 66ms
memory: 159896kb

input:

100

output:

188898954

result:

ok 1 number(s): "188898954"

Test #5:

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

input:

4

output:

10

result:

ok 1 number(s): "10"

Test #6:

score: 0
Accepted
time: 89ms
memory: 159864kb

input:

8

output:

12336

result:

ok 1 number(s): "12336"

Test #7:

score: 0
Accepted
time: 97ms
memory: 159848kb

input:

16

output:

373118483

result:

ok 1 number(s): "373118483"

Test #8:

score: 0
Accepted
time: 67ms
memory: 159848kb

input:

32

output:

314585464

result:

ok 1 number(s): "314585464"

Test #9:

score: 0
Accepted
time: 81ms
memory: 159808kb

input:

64

output:

627827331

result:

ok 1 number(s): "627827331"

Test #10:

score: 0
Accepted
time: 86ms
memory: 159836kb

input:

128

output:

828497685

result:

ok 1 number(s): "828497685"

Test #11:

score: 0
Accepted
time: 74ms
memory: 159912kb

input:

256

output:

65697890

result:

ok 1 number(s): "65697890"

Test #12:

score: 0
Accepted
time: 84ms
memory: 159764kb

input:

512

output:

854187619

result:

ok 1 number(s): "854187619"

Test #13:

score: 0
Accepted
time: 86ms
memory: 159832kb

input:

1024

output:

513823539

result:

ok 1 number(s): "513823539"

Test #14:

score: 0
Accepted
time: 83ms
memory: 159876kb

input:

1361956

output:

617368199

result:

ok 1 number(s): "617368199"

Test #15:

score: 0
Accepted
time: 108ms
memory: 159800kb

input:

7579013

output:

827172636

result:

ok 1 number(s): "827172636"

Test #16:

score: 0
Accepted
time: 95ms
memory: 159908kb

input:

8145517

output:

710624331

result:

ok 1 number(s): "710624331"

Test #17:

score: 0
Accepted
time: 107ms
memory: 159848kb

input:

6140463

output:

707600568

result:

ok 1 number(s): "707600568"

Test #18:

score: 0
Accepted
time: 94ms
memory: 159836kb

input:

3515281

output:

698302413

result:

ok 1 number(s): "698302413"

Test #19:

score: 0
Accepted
time: 99ms
memory: 159828kb

input:

6969586

output:

69470392

result:

ok 1 number(s): "69470392"

Test #20:

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

input:

2888636

output:

433579983

result:

ok 1 number(s): "433579983"

Test #21:

score: 0
Accepted
time: 118ms
memory: 159760kb

input:

9999998

output:

758172780

result:

ok 1 number(s): "758172780"

Test #22:

score: 0
Accepted
time: 133ms
memory: 159760kb

input:

9999999

output:

605195495

result:

ok 1 number(s): "605195495"

Test #23:

score: 0
Accepted
time: 120ms
memory: 159760kb

input:

10000000

output:

866813682

result:

ok 1 number(s): "866813682"