Cod sursa(job #520089)
Utilizator | Costea Bogdan bogdan353 | Data | 7 ianuarie 2011 13:32:12 |
---|---|---|---|
Problema | Fractii | Scor | 80 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.42 kb |
#include<iostream>
#include<fstream>
using namespace std;
long long n,i,s=0,p,t;
int a[1000001];
int main()
{
ifstream f("fractii.in");
ofstream g("fractii.out");
f>>n;
for(i=2;i<=n;i++)
a[i]=i-1;
for(i=2;i<=n;i++)
{p=i;
t=2;
s=s+a[i];
while(p<=n)
{
p=t*i;
a[p]=a[p]-a[i];
t++;
}
}
g<<2*s+1;
return 0;
}