Cod sursa(job #669941)

Utilizator Victor10Oltean Victor Victor10 Data 28 ianuarie 2012 08:29:24
Problema Fractii Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.33 kb
Raporteaza aceasta sursa 
#include <cstdio>
int v[1000005];
int main(){
	int n,i,j;
	long long rez=0;
	freopen("fractii.in","r",stdin);
	freopen("fractii.out","w",stdout);
	scanf("%d",&n);
	for(i=2;i<=n ; ++i )
		v[i]=i-1;
	for( i=2 ; i<n ; i++ ){
		for( j=i+i; j<=n; j+=i )
			v[j]-=v[i];
		rez+=v[i];
	}
	rez+=v[i];
	printf("%lld",2*rez+1);
}