Cod sursa(job #530171)

Utilizator ioanabIoana Bica ioanab Data 7 februarie 2011 08:50:34
Problema Suma divizorilor Scor 10
Compilator cpp Status done
Runda Arhiva de probleme Marime 1.24 kb
#include <fstream>
using namespace std;


const int N=1000005;
const int m=9901;
bool c[N];
int v[N];
int inv[10000];

ifstream in("sumdiv.in");
ofstream out("sumdiv.out");

void ciur()

{
	int i,j,n;
	for(i=2;i*i<N;++i)
		if(!c[i])
			for(j=i*i;j<N;j+=i)
				c[j]=true;
	n=0;
	for(i=2;i<N;i++)
		if(c[i]==false)
			v[++n]=i;
}

long long Fast_pow(long long a, long long b)
{
	long long p;
	if(b==0)
		return 1;
	if(b==1)
		return a%m;
	p=Fast_pow(a%m,b/2);
	if(b%2==0)
		return (p%m * p%m) %m;
	if(b%2==1)
		return ((p%m * p%m)%m*a%m)%m;
	return 0;

}

int invers(int x)
{
	int i;
	for(i=1;i<=m;i++)
		if((i*x)%m==1)
		{
			inv[i]=x;
			inv[x]=i;
			return i;
		}
	return 0;
}



int main()
{
	
	long long i,p;
	long long suma,a,b,x;
	ciur();
	in>>a>>b;
	suma=1;
	
		
	for(i=1;v[i]*v[i]<=a;++i)
		if(a%v[i]==0)
		{
				p=0;
				while(a%v[i]==0)
				{
					++p;
					a/=v[i];
				}
				x=p*b+1;
				if(inv[v[i]]-1==0)
					invers(v[i]-1);
				suma=suma*(Fast_pow(v[i],x)-1)*(inv[v[i]-1]);
				suma=suma%9901;
		}
	
		if(a!=1)
		{
			x=b+1;
			if(inv[a-1]==0)
				invers(a-1);
			suma=suma*(Fast_pow(a,x)-1)*(inv[a-1]);
			suma=suma%9901;
		}
		out<<suma;

	return 0;
}