Cod sursa(job #2180775)

Utilizator alexradu04Radu Alexandru alexradu04 Data 21 martie 2018 09:55:36
Problema Mins Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.88 kb
#include<cstdio>
using namespace std;

int c,d;
int nr[1000005];
bool p[1000005];
void ciur(int n)
{
     for(int i=2;i<=n;++i)
    {
        if(nr[i]) 
            continue ;
        for(int j=i;j<=n;j+=i)
            ++nr[j];
        if(n/i<i) 
            continue;
        for(int j=i*i;j<=c;j+=i*i)
            p[j] = 1;
    }
}
int main()
{
    freopen("mins.in","r",stdin);
    freopen("mins.out","w",stdout);
    scanf("%d %d",&c,&d);
    if(c>d) 
        {
            int aux=c;
            c=d;
            d=aux;
        }
    c--;
    d--;
    ciur(c);
    long long ans=1LL*c*d;
    for(int i=2;i<=c;++i)
        {
            if(p[i]) 
                continue ;
            if(nr[i]%2==0)
                ans=ans+1LL*(c/i)*(d/i);
            else
                ans=ans-1LL*(c/i)*(d/i);
        }
    printf("%lld\n",ans);
    return 0;
}