Cod sursa(job #2879356)

Utilizator Uriesu_IuliusUriesu Iulius Uriesu_Iulius Data 28 martie 2022 14:51:31
Problema Principiul includerii si excluderii Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.61 kb
#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define ipair pair<int, int>

ifstream fin("pinex.in");
ofstream fout("pinex.out");

const int mxP=1e6;
ll a, b, ans;
bool prime[mxP+1];
vector<ll> primes, factors;

void primeNumbers()
{
    for(int i=2; i*i<=mxP; i++)
        if(!prime[i])
            for(int j=i*i; j<=mxP; j+=i)
                prime[j]=1;
    primes.push_back(2);
    for(int i=3; i<=mxP; i+=2)
        if(!prime[i])
            primes.push_back(i);
}

vector<ll> primeFactors(ll x)
{
    vector<ll> ans;
    int i=0;
    ll d=primes[0];
    while(x>1)
    {
        int p=0;
        while(x%d==0)
        {
            p++;
            x/=d;
        }
        if(p)
            ans.push_back(d);
        i++;
        if(i==primes.size())
            d=x;
        else
        {
            d=primes[i];
            if(d*d>x)
                d=x;
        }
    }
    return ans;
}

void solve()
{
    fin >> a >> b;
    if(b==1)
    {
        fout << a << "\n";
        return;
    }
    factors=primeFactors(b);
    ans=0;
    int lim=pow(2, factors.size())-1;
    for(int i=1; i<=lim; i++)
    {
        int cnt=0;
        ll p=1;
        for(int j=0; j<factors.size(); j++)
            if(i&(1<<j))
            {
                cnt++;
                p*=factors[j];
            }
        if(cnt%2==1)
            ans+=a/p;
        else
            ans-=a/p;
    }
    fout << a-ans << "\n";
}

int main()
{
    int t;
    fin >> t;
    primeNumbers();
    for(int i=0; i<t; i++)
        solve();
    return 0;
}