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ID题目提交者结果用时内存语言文件大小提交时间测评时间
#362061#6736. Alice and Bobproven#AC ✓122ms161828kbC++201.7kb2024-03-23 14:01:132024-03-23 14:01:13

Judging History

你现在查看的是最新测评结果

  • [2024-03-23 14:01:13]
  • 评测
  • 测评结果:AC
  • 用时:122ms
  • 内存:161828kb
  • [2024-03-23 14:01:13]
  • 提交

answer

#include <bits/stdc++.h>
using namespace std;
#define fs first
#define endl '\n'
#define sc second
#define pb push_back
#define int long long
#define bit(x) (1ll << (x))
#define sz(x) (int)(x).size()
#define al(x) (x).begin(),(x).end()
#define all(x) (x).begin() + 1,(x).end()
using LL = long long;
using VI = vector <int>;
using VS = vector <string>;
using PII = pair <int, int>;
using I64 = unsigned long long;
using VVI = vector < vector<int> >;
template<LL N> using AL = array<LL, N>;
template<int N> using AI = array<int, N>;
const int inf = bit(60), mod = 998244353, N = 1e7 + 6;

int fpow(int x, int t = mod - 2) {
    int res = 1;
    for (; t; t >>= 1, x = 1ll * x * x % mod)
        if (t & 1) res = 1ll * res * x % mod;
    return res;
}

int fac[N], ifac[N], deg[N], ans[N];

int C(int n, int m) {
    if (n < m) return 0;
    return 1ll * fac[n] * ifac[m] % mod * ifac[n - m] % mod;
}

void init() //这里是处理阶乘和每个数字的逆元,fac[i]存的是i!,ifac[i]存的是i!的逆元,方便运算
{
    fac[0] = ifac[0] = 1;
    for (int i = 1; i < N; ++i) fac[i] = 1ll * fac[i - 1] * i % mod;
    ifac[N - 1] = fpow(fac[N - 1]);
    for (int i = N - 2; i; --i) ifac[i] = 1ll * ifac[i + 1] * (i + 1) % mod;
}

void solve() {
    init();
    int n; cin >> n;
    int res = 0;
    for(int i = 1;i * 2 - 1 <= n;i++) {
        res = (res + C(n - i, i - 1) * fac[i - 1] % mod * fac[n - i] % mod) % mod;
    }
    cout << res << endl;
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    cout << fixed << setprecision(10);
    int T = 1;
//    cin >> T;
    while(T--) solve();

    return 0;
}

详细

Test #1:

score: 100
Accepted
time: 64ms
memory: 160816kb

input:

1

output:

1

result:

ok 1 number(s): "1"

Test #2:

score: 0
Accepted
time: 36ms
memory: 160696kb

input:

2

output:

1

result:

ok 1 number(s): "1"

Test #3:

score: 0
Accepted
time: 39ms
memory: 160460kb

input:

10

output:

997920

result:

ok 1 number(s): "997920"

Test #4:

score: 0
Accepted
time: 56ms
memory: 160300kb

input:

100

output:

188898954

result:

ok 1 number(s): "188898954"

Test #5:

score: 0
Accepted
time: 104ms
memory: 160784kb

input:

4

output:

10

result:

ok 1 number(s): "10"

Test #6:

score: 0
Accepted
time: 75ms
memory: 160900kb

input:

8

output:

12336

result:

ok 1 number(s): "12336"

Test #7:

score: 0
Accepted
time: 71ms
memory: 160660kb

input:

16

output:

373118483

result:

ok 1 number(s): "373118483"

Test #8:

score: 0
Accepted
time: 80ms
memory: 160428kb

input:

32

output:

314585464

result:

ok 1 number(s): "314585464"

Test #9:

score: 0
Accepted
time: 81ms
memory: 161360kb

input:

64

output:

627827331

result:

ok 1 number(s): "627827331"

Test #10:

score: 0
Accepted
time: 95ms
memory: 161568kb

input:

128

output:

828497685

result:

ok 1 number(s): "828497685"

Test #11:

score: 0
Accepted
time: 103ms
memory: 161488kb

input:

256

output:

65697890

result:

ok 1 number(s): "65697890"

Test #12:

score: 0
Accepted
time: 88ms
memory: 160484kb

input:

512

output:

854187619

result:

ok 1 number(s): "854187619"

Test #13:

score: 0
Accepted
time: 99ms
memory: 160184kb

input:

1024

output:

513823539

result:

ok 1 number(s): "513823539"

Test #14:

score: 0
Accepted
time: 91ms
memory: 160716kb

input:

1361956

output:

617368199

result:

ok 1 number(s): "617368199"

Test #15:

score: 0
Accepted
time: 111ms
memory: 161672kb

input:

7579013

output:

827172636

result:

ok 1 number(s): "827172636"

Test #16:

score: 0
Accepted
time: 85ms
memory: 161732kb

input:

8145517

output:

710624331

result:

ok 1 number(s): "710624331"

Test #17:

score: 0
Accepted
time: 109ms
memory: 160968kb

input:

6140463

output:

707600568

result:

ok 1 number(s): "707600568"

Test #18:

score: 0
Accepted
time: 101ms
memory: 160200kb

input:

3515281

output:

698302413

result:

ok 1 number(s): "698302413"

Test #19:

score: 0
Accepted
time: 52ms
memory: 161828kb

input:

6969586

output:

69470392

result:

ok 1 number(s): "69470392"

Test #20:

score: 0
Accepted
time: 83ms
memory: 161048kb

input:

2888636

output:

433579983

result:

ok 1 number(s): "433579983"

Test #21:

score: 0
Accepted
time: 71ms
memory: 159984kb

input:

9999998

output:

758172780

result:

ok 1 number(s): "758172780"

Test #22:

score: 0
Accepted
time: 122ms
memory: 160744kb

input:

9999999

output:

605195495

result:

ok 1 number(s): "605195495"

Test #23:

score: 0
Accepted
time: 103ms
memory: 159904kb

input:

10000000

output:

866813682

result:

ok 1 number(s): "866813682"