Cod sursa(job #377372)

Utilizator aghamatMorariu Razvan aghamat Data 24 decembrie 2009 12:02:17
Problema Invers modular Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.59 kb
#include <stdio.h>

#define ll long long

int A, N;

void gcd(ll &x, ll &y, int a, int b)  
{  
     if (!b)  
         x = 1, y = 0;  
     else  
     {             
         gcd(x, y, b, a % b);
         ll aux = x;
         x = y;
         y = aux - y * (a / b);
     }
}

int main()
{
    ll inv = 0, ins;
    
    freopen("inversmodular.in", "r", stdin);
    freopen("inversmodular.out", "w", stdout);
    
    scanf("%d %d", &A, &N);
    gcd(inv, ins, A, N);

    if (inv <= 0)
       inv = N + inv % N;
       
    printf("%lld\n", inv);
      
    return 0;
}