Cod sursa(job #2788171)

Utilizator M05IonutIonut Martinescu M05Ionut Data 25 octombrie 2021 10:45:17
Problema Fractii Scor 10
Compilator cpp-64 Status done
Runda Arhiva de probleme Marime 0.64 kb
#include <iostream>
#include <fstream>


using namespace std;


ifstream fin("fractii.in");
ofstream fout("fractii.out");


int  N, cnt=0;

int x[20];

int cmmdc(int a, int b)
{
    while(a!=b)
    {
        if(a>b)
            a=a-b;
        else
            b=b-a;
    }
    return b;
}

int valid(int k)
{
    for(int i=1;i<k;i++)
        if(cmmdc(x[i], x[k])!=1)
           return 0;

    return 1;
}
void back(int k)
{
	for (int i = 1; i <= N; i++)
	{
		x[k] = i;
		if (valid(k))
			if (k == 2)
				cnt++;
			else
				back(k + 1);
	}
}
int main()
{
	fin >> N;
	back(1);
	fout << cnt;
	return 0;
}