Cod sursa(job #476075)

Utilizator dushmiMihai-Alexandru Dusmanu dushmi Data 9 august 2010 18:03:08
Problema Mins Scor 80
Compilator cpp Status done
Runda Arhiva de probleme Marime 1.18 kb
#include<cstdio>
int tot,x,y,n,pr[10],sol[10],rez[1<<20],v[1<<20][10];
short int lung[1<<20];
void read()
{
    freopen("mins.in","r",stdin);
    freopen("mins.out","w",stdout);
    scanf("%d%d",&x,&y);
}
void add(int a,int b)
{
    int nrt=1,q=0;
    for(int i=1;i<=n;i++)
        if(sol[i]==1)
            nrt*=v[b][i], q++;
    if(q%2==0 && q)
        tot-=(a/nrt);
    else if(q) tot+=(a/nrt);
}
void back(int poz,int a,int b)
{
    if(poz>n)
    {
        add(a,b);
        return;
    }
    sol[poz]=0;
    back(poz+1,a,b);
    sol[poz]=1;
    back(poz+1,a,b);
}
int calc(int a,int b)
{
    n=lung[b];
    tot=0;
    back(1,a,b);
    return a-tot;
}
void init()
{
    for(int i=1;i<=x;i++)
       v[i][0]=1;
}
void solve()
{
    init();
    rez[1]=y-1;
    for(int i=2;i<x;i++)
    {
        if(v[i][0]==1)
            for(int j=i;j<=x;j+=i)
                v[j][0]*=i, v[j][++lung[j]]=i;
        if(v[i][0]==i)
            rez[i]=calc(y-1,i);
        else rez[i]=rez[v[i][0]];
    }
    long long rasp=0;
    for(int i=1;i<=x;i++)
        rasp+=rez[i];
    printf("%lld",rasp);
}
int main()
{
    read();
    solve();
    return 0;
}