Cod sursa(job #819856)

Utilizator assa98Andrei Stanciu assa98 Data 19 noiembrie 2012 19:43:03
Problema Frac Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 1.3 kb
#include <stdio.h>

long long fact[100];
int cf;

void descompune(long long x)
{
    if(x%2==0)
    {
        fact[++cf]=2;
        while(x%2==0)
            x/=2;
    }
    long long d=3;
    while(x!=1)
    {
        if(x%d==0)
        {
            fact[++cf]=d;
            while(x%d==0)
                x/=d;
        }
        d+=2;
    }
}

long long n;

long long subm(long long p)
{
    int b;
    long long sol=p;
    long long prod;
    int cate;
    for(long long i=1;i<(long long)1<<cf;i++)
    {
        prod=1;
        cate=0;
        for(b=0;b<cf;b++)
        {
            if((1<<b)&i)
            {
                cate++;
                prod*=fact[b+1];
            }
        }
        if(cate%2==1)
            sol-=p/prod;
        else
            sol+=p/prod;
    }
    return sol;
}

long long p;
long long rez;

void bsearch(long long s,long long d)
{
    if(s>d)
        return;
    else
    {
        long long mij=(s+d)/((long long)2);
        long long x=subm(mij);
        if(x==p)
            rez=mij;
        if(x<p)
            bsearch(mij+1,d);
        else
            bsearch(s,mij-1);
    }
}

int main()
{
    freopen("frac.in","r",stdin);
    freopen("frac.out","w",stdout);
    scanf("%lld%lld",&n,&p);
    descompune(n);
    bsearch(1,(long long)1<<61);
    printf("%lld",rez);
    return 0;
}