Cod sursa(job #2503077)

Utilizator Arina2003Arina Aioanei Arina2003 Data 2 decembrie 2019 12:21:19
Problema Dirichlet Scor 100
Compilator cpp-64 Status done
Runda Arhiva de probleme Marime 0.79 kb
#include <fstream>

using namespace std;

const int MOD = 9999991;

ifstream f("dirichlet.in");
ofstream g("dirichlet.out");

void EuclidExtins(int a, int b, int &d, int &x, int &y) //Varianta recursiva
{
    if(b == 0)
    {
        x = 1;
        y = 0;
        d = a;
    }
    else
    {
        int x0, y0;
        EuclidExtins(b, a % b, d, x0, y0);
        x = y0;
        y = x0 - (a / b) * y0;
    }
}

int InversMod(int a)///,int n)
{
    int d,x,y;
    EuclidExtins(a,MOD,d,x,y);
    x%=MOD;
    if(x<0)
        x+=MOD;
    return x;
}

int main()
{
    int n;
    f>>n;
    long long a = 1, b = 1;
    for(int i=2;i<=n;i++)
    {
        a = 1LL * a * (n+i) % MOD;
        b = 1LL * b * i % MOD;
    }
    g<< a * InversMod(b) % MOD;
    return 0;
}