Cod sursa(job #2211822)
Utilizator | tudor voicu Fantastic_Man | Data | 11 iunie 2018 22:26:36 |
---|---|---|---|
Problema | Fractii | Scor | 0 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.49 kb |
#include <iostream>
#include <stdio.h>
using namespace std;
int cr[1000001];
int main()
{
freopen("fractii.in","r",stdin);
freopen("fractii.out","w",stdout);
int n,i,r,j;
unsigned long long sum=0;
scanf("%d",&n);
for(i=1;i<=n;i++) cr[i]=i;
for(i=1;i<=n;i++) {
sum+=cr[i];
r=n/i;
for(j=2;j<=r;j++)
ciur[i*j]-=ciur[i];
}
/**
p/q e ireductibila <=> q/p e ireductibila
scadem fr 1/1
**/
cout<<2*sum-1;
return 0;
}