Submission #38485641

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Source Code Expand

#include<bits/stdc++.h>
#define LL long long
#define MOD 998244353
using namespace std;
int mul(const int &a, const int &b)
{
    return 1LL * a * b % MOD;
}
void Inc(int &a, const int &b)
{
    ((a += b) >= MOD) && (a -= MOD);
}
void Mul(int &a, const int &b)
{
    a = 1LL * a * b % MOD;
}
void Sqr(int &a)
{
    a = 1LL * a * a % MOD;
}
int qwqmi(int x, int k = MOD - 2)
{
    int res = 1;
    while(k)
    {
        if(k & 1) Mul(res, x);
        Sqr(x), k >>= 1;
    }
    return res;
}
const int N = 1e7 + 5;
int n, ans, f[N], inv[N];
int main()
{
    scanf("%d", &n);
    inv[1] = 1;
    f[0] = 1, f[1] = 6 * n;
    for(int i = 2; i < n; ++i)
    {
        f[i] = mul(3 *(2 * n - i + 1), f[i - 1]);
        Inc(f[i], mul(4 * n - i + 2, f[i - 2]));
        inv[i] = mul(inv[MOD % i], MOD - MOD / i);
        Mul(f[i], inv[i]);
    }
    ans = mul(f[n - 1], qwqmi(n));
    printf("%d\n", ans);
    return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:35:10: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   35 |     scanf("%d", &n);
      |     ~~~~~^~~~~~~~~~

Judge Result