Cod sursa(job #996525)
Utilizator | Ulmeanu Vlad vlad.ulmeanu30 | Data | 12 septembrie 2013 11:01:38 |
---|---|---|---|
Problema | Fractii | Scor | 30 |
Compilator | c | Status | done |
Runda | Arhiva de probleme | Marime | 0.45 kb |
#include<stdio.h>
#define NRMAX 1000010
int v[NRMAX];
int main()
{
FILE *f, *g;
int n,rez=0,i,j;
f=fopen("fractii.in","r");
g=fopen("fractii.out","w");
fscanf(f,"%d",&n);
for(i=1;i<=n;i++)
v[i]=i-1;
for(i=2;i<=n;i++)
for(j=2*i;j<=n;j+=i)
v[j]-=v[i];
for(i=1;i<=n;i++)
rez=rez+v[i];
fprintf(g,"%d",rez*2+1);
fclose(f);
fclose(g);
return 0;
}