Cod sursa(job #2158307)

Utilizator razvanradulescuRadulescu Razvan razvanradulescu Data 10 martie 2018 11:53:01
Problema Principiul includerii si excluderii Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 1.31 kb
#include <iostream>
#include <cstdio>
#include <bitset>
using namespace std;

bool sir[1000000];
int diviz[80000], k = 0, n, a, b;

void ciur()
{
    for(int i = 4; i<=1000000; i+=2)
        sir[i] = 1;
    for(int i = 3; i<=1000000; i+=2)
    {
        if(sir[i] == 0)
        {
            for(int j = i*3; j<=1000000; j+=i)
            {
                sir[j] = 1;
            }
        }
    }
}

void rez()
{
    scanf("%d %d", &a, &b);
    k = 0;
    if(b&1 == 0)
        diviz[k++] = 2;
    int d = 3;
    for(; d*d<=b; d+=2)
        if(sir[d] == 0)
            diviz[k++] = d;
    if(sir[b] == 0)
        diviz[k++] = b;
    int v = (1<<k);
    int prod = 1, nrsub = 0, suma = 0;
    for(int nr = 0; nr<v; nr++)
    {
        for(int j = 0; j<k; j++, nrsub = 0)
        {
            if(nr&(1<<j))
            {
                prod*=diviz[j];
                nrsub++;
            }
            if(nrsub&1 == 1 && nrsub!=0)
                suma+=a/prod;
            else if(nrsub!=0)
                suma-=a/prod;
        }
        prod = 1;
    }
    printf("%d\n", a-suma);
}

int main()
{
    freopen("pinex.in", "r", stdin);
    freopen("pinex.out", "w", stdout);
    scanf("%d", &n);
    ciur();
    for(int i = 0; i<n; i++)
        rez();
    return 0;
}