Cod sursa(job #482972)

Utilizator AndreiRSStatescu Andrei Rares AndreiRS Data 6 septembrie 2010 13:32:20
Problema Fractii Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.33 kb
Raporteaza aceasta sursa 
#include <stdio.h>

int N, X[1<<20];
long long F;

int main () {
	freopen ("fractii.in", "r", stdin);
	freopen ("fractii.out", "w", stdout);
	
	scanf ("%d", &N);
	
	for (int i=2; i<=N; ++i) {
		F += i - X[i] - 1;
		for (int j=i+i; j<=N; j+=i)
			X[j] += i - X[i] - 1;
	}
	
	printf ("%lld", 1+F+F);
	
	return 0;
}