Cod sursa(job #227473)

Utilizator mariusdrgdragus marius mariusdrg Data 4 decembrie 2008 19:09:45
Problema Invers modular Scor Ascuns
Compilator cpp Status done
Runda Marime 0.58 kb
#include<stdio.h>
#define LL long long


LL N,M;

LL getphi(LL nr)
{
	LL cur = nr;
	for(LL i = 2;i * i <= nr; ++i)
	{
		if (nr % i == 0)
		{
			while(nr % i == 0)nr /= i;
			cur = (cur / i) * (i - 1);
		}
	}
        if (nr != 1) cur = cur / nr * (nr - 1);
	return cur;
}

int main()
{
	freopen("inversmodular.in","r",stdin);
	freopen("inversmodular.out","w",stdout);
	scanf("%lld %lld\n",&N,&M);
        LL put = getphi(M) - 1;
	LL nr = N;
	LL crt = 1;
    for(LL p = 1;p <= put;p <<= 1)
    {
	 	if (p & put) crt = (crt * nr) % M;
	  	nr = (nr * nr) % M;
	}
	printf("%lld\n",crt);
	return 0;
}