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QOJ

IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#399141#6736. Alice and BobqionghuaWA 1ms5728kbC++201.5kb2024-04-25 22:58:402024-04-25 22:58:44

Judging History

你现在查看的是最新测评结果

  • [2024-04-25 22:58:44]
  • 评测
  • 测评结果:WA
  • 用时:1ms
  • 内存:5728kb
  • [2024-04-25 22:58:40]
  • 提交

answer

#include <bits/stdc++.h>
#include <chrono>
using namespace std;
#define endl '\n'
//#define inf 1e18
typedef long long ll;
typedef unsigned long long ull;
typedef __int128 lll;
typedef pair<ll, ll> P;
#define x first
#define y second

// const int p = 1e9 + 7;
const int pp = 998244353;

int dx[8] = {-1, 0, 1, 0, -1, -1, 1, 1}, dy[8] = {0, 1, 0, -1, -1, 1, -1, 1};
int ddx[8] = {1, 1, 2, 2, -1, -1, -2, -2}, ddy[8] = {2, -2, 1, -1, 2, -2, 1, -1};

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

const int N = 1e7 + 1;
int f[N], g[N];
void init(int n) {
    f[0] = g[0] = f[1] = g[1] = 1;
    for(int i = 2; i <= n; ++ i ) {
        f[i] = 1ll * f[i - 1] * i % pp;
        if (n & 1 && (i % 2 == 0)) g[i] = 1ll * g[i - 1] * ksm(i, pp - 2, pp) % pp;
        if ((n % 2 == 0) && i & 1) g[i] = 1ll * g[i - 1] * ksm(i, pp - 2, pp) % pp;
    }
}

void solve() {
    int n;
    cin >> n;
    init(n);
    int ans = 0;
    for(int p1 = 1; p1 <= n / 2 + 1; ++ p1) {
        int now =  1ll * g[n - p1 - p1 + 1] * f[n - p1] % pp * f[n - p1] % pp;
//         cout << "p1 : " << p1 << ", now : " << now << endl;
        ans = (ans + now) % pp;
    }
    cout << ans << endl;
}


/*	



*/

signed main () {
    // init(minp, primes, m); // primes
    ios::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);
    int _ = 1;
//   cin >> _;
    while(_ -- ) {
        solve();
    }
    return 0;
}

Details

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Test #1:

score: 100
Accepted
time: 1ms
memory: 5724kb

input:

1

output:

1

result:

ok 1 number(s): "1"

Test #2:

score: 0
Accepted
time: 0ms
memory: 5716kb

input:

2

output:

1

result:

ok 1 number(s): "1"

Test #3:

score: -100
Wrong Answer
time: 1ms
memory: 5728kb

input:

10

output:

14400

result:

wrong answer 1st numbers differ - expected: '997920', found: '14400'